There are several aspects of vegetable harvesting. In this post I will look first at maturity indicators, then at four ranges of cold-hardy crops for harvest at various stages of winter, followed by a reminder of the order for harvesting storable crops, according to the coldest temperature they can take. After that I have links to a couple of other websites with great information on these topics, a mention of two articles on seed saving and one on garlic planting I have in Growing for Market magazine. And a link to a Mother Earth News Fair Online workshop on establishing winter cover crops.
Harvest and Maturity Indicators
Don’t harvest too soon or too late. How do you know when it’s ready to harvest? Different factors are important for different crops. Use all your senses.
Size: Cow Horn okra at 5”/13 cm (others shorter), green beans a bit thinner than a pencil, carrots at whatever size you like, 7”/18 cm asparagus, 6”/15 cm zucchini
Color: Garden Peach tomatoes with a pink flush. The “ground spot” of a watermelon turns from greenish white to buttery yellow at maturity, and the curly tendrils where the stem meets the melon to turn brown and dry. For market you may harvest “fruit” crops a bit under-ripe
Shape: cucumbers that are rounded out, not triangular in cross-section, but not blimps. Sugar Ann snap peas get completely round before they reach peak sweetness.
Softness or texture: eggplants that “bounce back” when lightly squeezed, snap beans that are crisp with pliable tips. Harvest most muskmelons when the stem separates easily from the fruit (“Full slip”).
Skin toughness: storage potatoes when the skins don’t rub off, usually two weeks after the tops die, whether naturally or because of mowing.
Sound: watermelons sound like your chest not your head or your belly when thumped. Try the “Scrunch Test” – press down firmly on the melon and listen and feel for the separation of the ripe flesh inside the melon.
Cabbages are fully mature when the head is firm and the outer leaf on the head is curling back. Ignore the separate “wrapper leaves” when making this judgment. If you need to keep mature cabbage in the ground a few days longer, twist the heads to break off some of the feeder roots and limit water uptake, and they will be less likely to split.
Select blue-green broccoli heads and harvest them before the flower buds open, but after they’ve enlarged. We press down with finger-tips and spread our fingers to see if the head is starting to loosen.
Sweet corn will be ready to harvest about three weeks after the first silks appear. Corn is ready when the ears fill to the end with kernels and the silks become brown and dry. An opaque, milky juice will seep out of punctured kernels. You can use your thumbnails to cur through the husk on the side and view the kernels. Don’t make your cut on top of the ear, or the dew and rain will get in and rot the corn.
Garlic is ready to harvest when the sixth leaf down is starting to brown on 50% of the crop. See Ron Engeland’s Growing Great Garlic. Harvesting too early means smaller bulbs (harvesting way too early means an undifferentiated bulb and lots of wrappers that then shrivel up). Harvesting too late means the bulbs may “shatter” or have an exploded look, and not store well.
Cut across hardneck garlic – airspaces around the stem show maturity
Wait until the tops fall over to harvest, then gently dig up the whole plant and dry. Leave the dry, papery outer skin on the onion for protection.
Four Ranges of Cold-Hardy Crops for Harvest at Various Stages of Winter
Crops to keep alive into winter to 22°-15°F (-6°C to -9°C), then harvest. Harvest and use soon: Asian greens, broccoli, cabbage, chard, lettuce, radishes. Harvest and store: beets, cabbage, carrots, celeriac, kohlrabi, winter radish (including daikon), rutabagas, turnips. Many greens and roots can survive some freezing, so it is worth experimenting to find how late you can keep crops outdoors.
Hardy winter-harvest crops: cabbage (Deadon), carrots, collards, kale, leeks, parsnips, scallions, spinach. We grow our winter-harvest crops in our raised bed area, which is more accessible in winter and more suited to small quantities.
Overwinter crops for spring harvests before the main season. Some crops, if kept alive through the winter, will start to grow again with the least hint of spring weather and be harvestable earlier than spring plantings. Depending on your climate, the list can include carrots, chard, chicories such as radicchio and sugarloaf, chives, collards, garlic, garlic scallions, kale, lettuce, multiplier onions (potato onions), scallions, spinach. In mild areas, peas can be fall sown for a spring crop. Sow 1″ (2.5 cm) apart to allow for extra losses.
Winter hoophouse crops: The rate of growth of cold-weather crops is much faster inside a hoophouse than outdoors. The crop quality, especially with leafy greens, is superb. Plants can tolerate lower temperatures than outdoors; they have warmer soil around their roots, and the pleasant daytime conditions in which to recover. Salad greens in a hoophouse can survive nights with outdoor lows of 14°F (–10°C) without inner rowcover.
In my post Root Crops in October, I gave this list of storable crops in the order for harvesting, related to how cold they can survive.
Clear and store (in this order):
Sweet potatoes 50°F (10°C)
“White” Peruvian potatoes 32°F (0°C) approximately
Celeriac 20°F (°C)
Turnips 20°F (°C)
Winter radish 20°F (°C)
Beets 15-20°F (°C)
Kohlrabi, 15°F (°C)
Carrots 12° F (°C)
Parsnips 0°F (°C)
Here are some links to a couple of good sources for more harvest information:
Prepare your garden for colder weather, plant winter crops where there is still time, harvest crops that will suffer from cold, construct low tunnels with rowcover or clear plastic to keep crops somewhat protected from wind and cold temperatures
I have written articles for Growing for Market magazine about growing and saving seeds (August and September issues), and planting garlic (October issue).
Given the shortages of some varieties this spring, it wouldn’t surprise us if more people tried producing seeds of vegetable or flower varieties this year. Here are links to articles from the August and September magazines, covering wet and dry seed processing.
Wet seed processing and saving
Wet seeds are embedded in fruit. Wet processing has four steps: scooping out the seeds or mashing the fruit, fermenting the seed pulp for several days, washing the seeds and removing the pulp and then drying the washed seeds.
Dry seeds develop in pods, husks or ears, and dry on the plant rather than inside a fruit. While you obviously want to get seeds into the hands of growers before they need to plant, and into seed catalogs before they get printed, often there is no urgency to extract the dry-seeded crops from their pods. You can wait for a slower time, or use seed cleaning as a rainy-day job.
Unlike white potatoes, which have the annual plant sequence of vegetative growth, flowering and dying back, sweet potato plants would go on growing forever if the weather remained warm enough. Choose when to dig them up, ahead of cold weather. The longer you wait, the bigger the potatoes, but you are gambling with the weather. Usually sweet potatoes are harvested in the week that the first frost typically occurs in your region. I have written plenty already in previous years about harvesting, so I won’t go into it here. See one of the links to those posts, or my slideshow, if you want to know what comes next, or your climate is considerably colder than mine in central Virginia.
Today I looked to see the “plenty” I had written in previous years, and was surprised not to find much! Every mid-October from 2012 to 2016, I mentioned sweet potato harvest, but many times it has been in passing, and mostly yield statistics (bragging or groaning). 2012 has the most detail on doing the harvest – read it below.
In 2019 we got a very nice yield and carried on eating sweet potatoes into September. Previously people seemed to lose interest in sweet potatoes in late May, and we would distribute our surplus to other people. This year we just kept eating and enjoying them. I can report that they did get wrinkly and grow big sprouts, but were still very tasty down to the last one in late September.
We now use electric fencing to keep the deer out, and grow on biodegradable plastic mulch to keep the weeds down, and use drip irrigation to grow the sweet potatoes up. These developments in our method became necessary over the years.
Yesterday we ate sweet potato leaves as a seasonal green. You can eat these throughout the growing season, but we usually don’t, as we hesitate to take away anything that is helping the tubers grow. But at harvest time, the leaves are about to return to the soil, so we clipped the vine tips and cooked them up. OK, interesting, never going to be a favorite for me, but perfectly acceptable, and less distracting than going off to harvest somehting else to eat in the middle of the big sweet potato harvest!
10/11/16: Yesterday we started harvesting our sweet potatoes. Yields look OK but not fantastic. We had a lot of problems with deer eating our sweet potatoes this year. We did have a temporary electric fence, but we often didn’t pay it good attention and it grounded out. Next year the rotation brings the sweet potatoes to a more traveled location. I can’t believe I’m already doing that “Gardener Survival Strategy” of thinking “Next Year Everything Will Be Perfect”!!
10/18/16: Our average first frost date is October 14. Actually from our own records it has averaged 10/22 over the last 11 years. . . . It’s good to be prepared.
10/20/15: We got our sweet potatoes all dug and safely indoors before Saturday night’s 27F and Sunday night’s 26F. Whew! Another Garden Year Milestone passed. We got about 223 boxes this year. The boxes contain about 23lbs each, so that’s 5129 lbs, plenty to feed 100 hungry people for six or seven months. . . . Our average harvest for this size patch (about 700 plants) is 4035lbs. This year we got a yield of a little over 7lbs of sweet potatoes per plant. Last year’s record crop was 11lbs per plant.
10/13/15: We are on the point of harvesting our sweet potatoes. After all the rain we had recently, we were waiting for the soil to dry enough to walk on. . . . I was worried for a couple of days that the weather would stay cold and the sweet potatoes might rot in the cold wet soil. One year when I was fairly new to Virginia I caused us to leave the sweet potatoes in the ground till early November (hoping they would grow a bit more) and then it rained hard and we ended up with a load of sweet potatoes that either rotted directly or else went through a transition to a hard uncookable state. I learned the hard way to harvest sweet potatoes before soil drops to 55F. This week I studied the soil thermometer and the max and min thermometer and was reassured by the warm sunny days. The soil has been drying out nicely. Tomorrow we start digging. It usually takes us three afternoons. Everything looks auspicious. No rain or horribly cold weather, enough people. . .
10/14/14: Our sweet potato harvest is huge this year! We mostly managed to keep the deer out of the plot, by luck and a scarecrow and things that fluttered in the breeze. We’ve filled all our usual boxes and then scrambled twice to find more! . . . . I counted the equivalent of 273 normal-sized boxes in the basement this morning. At 23 pounds for our standard box, that’s about 6280 pounds. We might be up to 6500 pounds by the time we’re done. This will be our record! I think our local food pantry will be getting some sweet potatoes this winter and next spring!
I compared sweet potato yields for different years. We usually have about 600 plants in 800 row feet (16″ spacing). Yield is about 11 pounds/sweet potato plant this year. But as they say “your results may vary.” Ours certainly have. Working back from 2012, we harvested 4070 lbs, 2208 lbs, 1860 lbs, “lots” (poor record-keeping!), 5590 lbs, 3820 lbs and 4050 lbs in 2007.
10/13/13, Sweet potatoes, statistics and inspiration: After a week of drizzle, it finally eased up and we started harvesting our sweet potatoes. . . . As usual, we set the dug roots in clusters, so we could see which plants yielded most and chose medium-sized roots from those to grow our slips next year. . . . This year, the Georgia Jet seem more productive than the Beauregard – I think that’s usual. We dug about a third of the crop the first day and got 86 boxes. The second day we had a lot of other harvesting (beans and broccoli being the most time-consuming), so we only dug another 36 boxes. . . .
Well . . . the yield dropped off a lot where the deer had been browsing (memo: fence out the deer in future!) We got a total of 177 boxes of various sizes, perhaps about 3939 pounds, almost two tons. . . .
Our yearly harvest of sweet potatoes has varied a lot, from 31 boxes (a sad year) to 243 in 2009. An average over ten years of 112 boxes, each weighing perhaps 23 pounds. . . . We always hope to have enough to last till the beginning of May, when people start to lose interest in sweet potatoes, and start hoping for tomatoes.
10/12/12: Usually sweet potatoes are harvested the week the first frost typically occurs. . . . Contrary to myth, there is no toxin that moves from frozen leaves down into the roots. On the other hand, cold injury can ruin the crop, and roots without leaf cover are exposed to cold air temperatures, and have lost their method of pulling water up out of the soil. Cold wet soil can quickly rot sweet potatoes (I know, it’s happened here).
To harvest, we first remove the vines from the area to be harvested that day. There is usually 3 afternoons’ digging for ours, and we want to leave live vines to protect the rest of the crop overnight. We use pruners to snip the vines where they emerge from the soil, leaving stumps to show where to dig. We roll the vines into the spaces between the rows.
Using digging forks, we carefully dig up the roots, which grow in the ground in a bunch-of-bananas shape. We want to select good potatoes for seed, and we grow several different kinds (Georgia Jet, Beauregard, and a couple of heritage varieties whose names we don’t know), so we make sure not to mix potatoes from different rows. As we dig, we set the potatoes out beside the spot where they’ve grown, one clump per plant, so it’s easy to identify the most productive plants.
It’s important not to bruise the roots, or to leave them exposed to temperatures higher than 90°F (32°C) for more than half an hour, or they will get sun-scald. Below 55°F (13°C), they’ll get chilling injury. We also avoid any abrasion of the skin, which is very fragile at this stage. We leave the sweet potatoes to dry on the ground for 1-2 hours, unless the weather is unsuitable. This year we had ideal weather, not too hot, not too cold, breezy enough to dry the skins, sunny.
We want to grow our own slips (baby plants) next year, so we save at least 1 root per 5 slips wanted. (1 good slip every 16″.) So to plant 800 row feet, (600 slips), we save 100 each of our two main varieties and 20 each of the two heirlooms. That should be plenty. Some will shrivel or rot, so we allow a margin. We don’t save for seed any roots that look diseased. We choose plants with a high yield and no string (rat-tail) roots. From these plants, we choose small-medium sized potatoes with typical shape and color.
When grading and crating the roots in the field, we first choose the seed potatoes, and then sort storable from “Use First” roots. Large open broken surfaces will cure and can be stored, but any roots with soft wet damaged areas or deep holes (whether from voles, bugs or fork tines) will not store, and should be graded out, for composting or immediate use. We sort into 4″ deep wood flats or 5″ plastic crates for curing, and buckets for the “Use First” category.
Immediately after harvest, we take the boxes of sweet potatoes into a warm damp basement below the dining hall, to cure. This allows the skin to thicken, cuts to heal over and some of the starches to convert to sugars. Uncured “green” sweet potatoes are not very sweet at all, and are better used in dishes where they combine with other foods. A baked uncured sweet potato is a sad disappointment.
We stack our boxes of roots on pallets, and put wooden spacer sticks between boxes in each stack, to ensure airflow. We get quite good temperatures, but keeping humidity up is difficult for us. We cover the flats with newspaper to hold in some moisture. The best result seems to come from splashing water on the concrete floor several times each day. We use box fans to improve the airflow, and the basement already has some natural ventilation.
Ideal conditions for curing are 85-90°F (29-32°C), and 80-95% humidity for 4-7 days, with some airflow and ventilation. Curing takes longer if conditions are less than perfect. The length of the curing period also varies with the dryness of the soil just prior to harvest. We usually reckon on 10-14 days. . . . .
So – how did we do this year? Middle of the road, I’d say. Decent yields, but not a bumper crop – we still had empty boxes left over. The deer were regularly eating our vines until quite recently. Last year we had a dog to chase the deer off, but he met with a road accident. His replacement was old, and she just wanted to be a pet, so we had deer again. We used drip irrigation and biodegradable plastic mulch this year, and did a good job of weeding, so I put the lower yields down to deer damage.
Root Crops to Plant in Central Virginia in October
We have now passed our last chances to sow root crops outdoors. But the exciting season in the hoophouse has just begun. In early October, we sow radishes in our hoophouse. See Root Crops in September for more about our succession of hoophouse radish sowing dates. We like Easter Egg (a multi-colored mix of red, plum, pink, purple and white varieties, that matures over several weeks), Cherry Belle, the fast, uniform red globes, and White Icicle, like baby daikon about 3” (7 cm) long. These three varieties all stay crunchy and tender. We have a dread of fibrous radishes! Most years we make a sowing at the beginning of October and another at the end, and these will feed us from early November until early February. The late October sowing lasts for 8 weeks, so it’s good to make sure we plant enough. Radishes do a lot to brighten up meals in December and January!
In mid-October (10/10-10/25), we sow our first of three plantings of hoophouse turnips. We like the very fast-growing and tender Hakureihybrid. It has short hairless tops which also make good eating. We sow this variety on the south side of the bed, leaving the other 3 rows for the taller varieties. We also like Early White Eggand Oasis, which are not quite as uniform as Hakurei, but are OPs and the seed is much cheaper. They produce more greens, which we value too. In the north row we often grow Red Round, a beautiful red-skinned turnip with tall attractive leaves. We also like Scarlet Ohno Revival, which has the advantage of hairless leaves. This is an Open Source Seed Initiative variety. The OSSI pledge: “You have the freedom to use these OSSI-Pledged seeds in any way you choose. In return, you pledge not to restrict others’ use of these seeds or their derivatives by patents or other means, and to include this pledge with any transfer of these seeds or their derivatives.”.
We thin the turnips as needed. If we sowed thickly, the first thinnings become baby greens for salad. Once the turnips are the size of marbles, we like to thin the plants to 3” (7 cm) apart and cook them whole, roots and greens together. The next thinning is to 6” (15 cm) and from that point on, we harvest the greens and roots separately. We get a ratio of one bucket of roots to two buckets of greens, which fits our needs perfectly. We like to mix the roots, as the one quarter of red roots adds a pop to the appearance.
Root Crops to Harvest in Central Virginia in October
We can continue harvesting beets (and beet greens), carrots, horseradish, kohlrabi, radishes, turnips (and turnip greens), and winter radishes outdoors. Once we have had a decisive frost we can harvest parsnips – the frost really improves the flavor. Our 9/6 sowing of hoophouse radishes will start to mature.
We tackle our process of clearing root crops and storing them, starting with celeriac (if we grew it this year). We start with the least cold tolerant roots and work our way to the most cold tolerant. This list is root crops only. See my list of Winter-Kill Temperatures of Cold-Hardy Winter Vegetables 2020 for a more complete picture of “Harvesting in Time”
Clear and store (in this order):
Sweet potatoes 50°F (10°C)
“White” Peruvian potatoes 32°F (0°C) approximately
Celeriac 20°F (°C)
Turnips 20°F (°C)
Winter radish 20°F (°C)
Beets 15-20°F (°C)
Kohlrabi, 15°F (°C)
Carrots 12° F (°C)
Parsnips 0°F (°C)
Wash, and store roots in perforated plastic bags in refrigerator or root cellar. We use a special measuring bucket lid to help new workers determine if roots are big enough to store.
Harvest sweet potatoes before soil temperatures go much below 55°F (13°C), or night air goes below 50°F (10°C). See the Special Topic below.
Harvest white potatoes when the skins have thickened. (When the skin is undamaged after rubbing two together. About 2 weeks after the tops die). See Harvesting Potatoes and Root Crops in June. Two or three days before harvesting, we spend the day removing the hay mulch from our 1600 row feet (488 m) potato patch to the compost area. Our potato digging machine can’t deal with mulch or heavy weeds. To fit with using machinery, we clear complete rows. We have a Perfect Potato Harvest Checklist. For fall harvesting we do the tractor work in the morning and pick up the potatoes in the afternoon, avoiding leaving any out overnight if it will be frosty. (When harvesting the March-planted potatoes in July, we do the tractor work early in the morning and start picking up the potatoes as soon as possible. We aim not to be outdoors after lunch when it’s hot, but if we need to, we will, as we don’t want ready-baked potatoes sitting on the soil!) Tractor time is 4 hrs x 2 people. Picking time is 30 people-hours.
For beets, we allow 6 people-hours per bed (360 row feet (110 m), and expect 2-3 50-pound (23 k) bags per bed. Cut the stems about ¼” (6 mm) above the root, to reduce “bleeding” when you cook the beets. I was reminded recently that not everyone knows that the easiest way to cook beets is to scrub them, boil them in the skins, drain and immerse in cold water, then simply slide the skins off. Hardly any wasted food and no wasted time.
For carrots, we allow 4.5-6.5 people-hours per (large) garden cart for washing, trimming and sorting. Plan to keep the last 15 minutes for clean-up. Divide the rest of the time available by 3. Use 1/3 of the time for digging, 2/3 of the time for washing and sorting. Add time to take to storage. Record yields. We take the carrot tops back and spread them across the beds. (fall harvest only ). In the spring and summer we take carrot tops to the compost pile, as the smell can attract carrot rust root flies. In late fall it is too late to sow cover crops to protect the soil, and the flies have gone to overwinter wherever they do that, so we spread the tops over the beds to provide some protection for the soil.)
Special Root Crop Topic for October in Central Virginia:
Harvest sweet potatoes
Here’s our method:
First roll up the drip tape. Harvest on 3 mild days – generally in the week that your first frost usually occurs (10/7-14). We expect our whole harvest of 800 row feet (244 m) to take 80 people hours. Allow 1/3 of the time for snipping, 1/3 for digging, 1/3 for crating and schlepping. Digging takes a bit less time than either of the other jobs. Even a few hours exposed to temperatures below 50°F (10°C) will cause chilling injury. (Frost on the leaves does not of itself damage the roots). Don’t leave clipped plants uncovered overnight. Don’t leave sweet potatoes outdoors. Clip the vines, dig carefully, set the tubers in plant-clusters to dry on the soil. Select seed tubers (healthy med-size tubers from high-yielding plants, no rat-tails). We save a generous 100 Georgia Jet, 100 Beauregard, 20 each of Bill Shane’s White and Jubilee. (These last two are unofficial names for varieties we were given and are maintaining for genetic diversity.)
Other Root Crop Tasks in Central Virginia in October:
Curing sweet potatoes and white potatoes
Cure sweet potatoes in collapsible, stackable holey crates (or in wooden flats with spacers for ventilation) and cover with newspaper on top, in a basement with the heater on, for 10-14 days (85-90°F, 27-32°C, 80-90% humidity) or longer if it’s cooler and drier. Use fans. Splash water on floor. Curing is complete when the skin is undamaged after rubbing two together. Restack the boxes (in a rodent-proof storage cage, if you are using an outbuilding).
Cure freshly harvested white potatoes in a root cellar at 60-75°F (15.5-24°C) for 2 weeks, with good ventilation, then cool cellar to lower temperature. See Special Topic for July. For weeks 2-4, the temperature goal is 50°F (10°C), and fresh air is needed about once a week. Our method of providing an air change in our cellar or adjusting the temperature is to leave the door open when the temperature will be closer to our goal than the current reality. It works well enough.
Day 5 – Saturday January 11 (Viñales) late afternoon
After lunch at Finca Paraiso restaurant and a tour of their beautiful farm, we visited
Finca L’Armonia (Ecological Permaculture Farm)
Our 27-year-old host farmer Yoani arrived on horseback. He is farming 1 hectare (2.2 acres) of his family of origin’s 13 hectares. It is a lovely farm. The farmer had twice been to France for permaculture training. His mother, sister, and grandfather farm the other 12 hectares as a coop that sells to the government (we saw part of this in a fenced area of shaded annual crops). He does permaculture on his portion.
He grows two varieties of coffee (trees his grandfather planted) and had coffee for sale in plastic water bottles. Because tourists are urged to drink only bottled water, empty water bottles are a convenient container for any kinds of seeds, as we saw at the bean seed conservation center, Finca Hoyo Bonito (see March 17 2020 post). He also grows passionfruit, avocado, pineapples, mangoes, and other fruit trees including Cuban pears.
He maintains worm bins and a composting toilet (top quality!) – the first composting toilet we saw on our tour. I am surprised there are not more composting toilets in the rural areas. Some tourist spots have horrible restrooms!
My room-mate Julia and I had dinner at our casa, cooked by our hosts. We had soup, salad, rice, red snapper fish, ice cream with honey. All delicious.
In the evening I did some shopping at a souvenir street market in Viñales.
Here is a video about this farm, from Franny’s Farmacy. Made by two of my fellow travelers on the OGS Tour.
To read more about the Organic Growers School organized trips and Cuban agriculture, see this article written by our fantastic tour guide Yoseti Herrera Guitián, who started working as a tour guide in 2013 with Amistur Cuba, a specialized tourism travel agency that is part of ICAP (Cuban Institute of Friendship with the Peoples). She has worked with diverse groups focused on topics such as health, education, culture and mostly agriculture. Open as a new page here: https://organicgrowersschool.org/cuba-through-the-seasons
Book Review: Soil Science for Gardeners, by Robert Pavlis, New Society Publishers, 2020. 228 pages, with charts and diagrams, $18.99.
I recommend this book to all gardeners who have hesitated to open a soil science text for fear of dry incomprehensible overloads of numbers. Robert Pavlis explains how your garden grows, and dashes cold water on false myths that may have been wasting your time and limiting your success for years! He leads us to a better understanding, including on a microscopic level, of soil biology, chemistry, physics, geology and ecology and to a place of wonder and curiosity at the everyday functioning of crops and soils.
This new comprehension can lead us to do right by our plants and our gardens, leading to healthier plants and higher yields. Robert writes in plain language, as a gardener with over 45 years of experience. He is the author of those Garden Myths books you might have seen. Perhaps, like me, you paid them little attention, thinking your own knowledge was fact-based. Even so, like me, you might find you had been holding onto some anti-facts (mine was that I believed compost is acidic – not so!). This book aims to have us understand real soil and make real improvements, via a Soil Health Action Plan at the end of the book.
The three sections of the book are Understanding Soil, Solving Soil Problems, and A Personalized Plan for Healthy Soil. A satisfying, logical sequence. Read the sections in the order presented! Robert says it’s very easy to grow plants if you understand the soil which anchors them, feeds them and provides the air and water they need to survive. With a solid understanding of what’s going on, you won’t need to memorize rules.
The 2016 definition of soil, by the Soil Science Academy of America is “Soil is the top layer of the Earth’s surface that generally consists of loose rock and mineral particles mixed with dead organic matter.” A rather bland underselling of what soil accomplishes. Here comes myth-bust #1: “Soil is not alive. It does not need to eat or breathe.” “The whole idea that soil is a living organism that requires similar attention to animals is completely false and leads to many poor recommendations for managing soil.” No, don’t give up here! It’s not the soil but the ecosystem of the soil and all the living organisms in and on it that holds the life. The ecosystem contains life, but is not itself alive.
Air and water are critical for good plant growth, about 25% of each. A simple, startling truth. The sand, silt and clay we might worry about make up another 45%, and 5% organic matter might fill out the total. A large tree can remove up to 100 gallons (400 liters) of water a day, discharging most of it into the air as water vapor. As the water leaves the soil, air is pulled in to fill the spaces. Roots pull the oxygen in, day and night, to convert sugars into energy. Were you also lead to believe that plants photosynthesized by day and respired only by night?
Did you know (I hadn’t thought about it) that “soil pH” is really an average of the pH of the water in the soil, and a spot with organic matter and lots of bacterial activity will have a very different pH from a spot with less organic matter? The rhizosphere (the area right around a plant’s roots) can have a very different pH from the soil solution further away. Plants can grow in alkaline soil because their roots are actually growing in acidic conditions. The nitrogen-fixing bacteria on legume roots cause the plant to release hydrogen ions, making the rhizosphere more acidic. To some extent, our efforts to change the soil pH can be undone by our crops and weeds! A soil property called buffer capacity lets the soil absorb materials at different pH and maintain its same level. Peat moss is acidic, but it does not acidify alkaline soil. The soil in the rhizosphere can be 2 pH units different from the soil around. This is usually written about in rather magical terms, but here it is in plain language.
Roots grow just fine where there is enough phosphorus. Adding more at transplanting doesn’t help, and can hinder. Visual plant symptoms can predict possible deficiencies, but are not a reliable diagnosis. Purple leaves may indicate phosphorus deficiency or cold temperatures, high light intensity, pest damage or lack of water. Or a nitrogen shortage reducing the plant’s ability to absorb phosphorus. There’s much that we don’t know!
Pay attention to the Cation Exchange Capacity – the measure of the soil’s ability to hold cations – because many plant nutrients are cations. You can increase the CEC by increasing the clay content, increasing the OM or increasing the pH. Read more in this book.
Have you ever thought about the “free” nitrogen from legume root nodules? Rethink of it as “homegrown” or “solar” rather than simply magic and free, because the leguminous plant may use up to 20% of the sugars produced during photosynthesis, to feed the bacteria.
Don’t justify your adherence to organic gardening by falsely claiming that synthetic fertilizers kill bacteria. Bacteria feed on both synthetic and organic fertilizers. This book challenges us to find the factual basis for choosing to grow organically, making us stronger advocates.
The bacteria chapter is followed by a chapter on fungi. Fungal spores are everywhere, even the Antarctic. Fungi are crucial for cleaning up plant litter on the soil surface. They grow above-ground hyphae which can penetrate dry leaves or wood chips and move the nutrients deep into the soil. Bacteria can’t tackle such tough stuff! 150 species of fungi capture and digest nematodes.
Why is organic matter important? This chapter explores the chemical and biological effects of organic matter on soil. Soil contains three forms of organic carbon: the living (15%), the dead and the very dead (stable humus and charcoal). Increasing the level of organic matter in the soil can increase aggregation, improve water infiltration (reducing runoff), increase aeration, increase water-holding capacity, improve tilth of clay soils, reduce crusting, and improve the size and distribution of the pore spaces. Those are just the physical effects. It will also increase the cation exchange capacity, increase the availability of nitrogen, boron, molybdenum, phosphorus and sulfur, and increase the microbial activity and diversity.
Often we think about adding partially decomposed OM such as compost and manure. We should face the reality that compost tends to have low levels of nutrients (maybe 1:1:1). The big value of these is in providing food for microbes, short-lived beings that provide a constant supply of fresh OM, multiplying its value. Partially decomposed compost takes about five years to finish decomposing, during which time it slowly releases nutrients. This gradual steady supply is what crops need. The humus left at the end is a complex molecular mixture of carbon, hydrogen and oxygen, resistant to further decay.
The initial effect of adding fresh OM (not composted OM) is an explosion of microbial reproduction, feeding and death. The microbes use nitrogen, which can cause plants to suffer a shortage. It takes time for a new balance to be achieved, providing adequate N for the plants. The needs for the N can encourage gardeners to add so much compost that the P level is too high, which can bring death to mycorrhizal fungi, leading to roots driving deeper to access their own P from the soil directly. We have very high soil P, a result of misunderstanding soil test limits. I have worried about it, then read more and stopped worrying. Soil P is pretty stable. If you are not leaching P into a waterway, it just stays in your soil until a plant need it. We switched to using less compost and more cover crops where we could. We were already using a lot of cover crops – it’s not like we were slouches in that department! After more time, I settled on accepting our situation, and as the plants show no sign of P-caused problems and our soil is bursting with earthworms, it doesn’t affect us much.
I mentioned at the beginning that I learned that finished compost is alkaline, not acidic. In the initial composting stage, acidity happens. Then fungi thrive, and decompose the tough lignin and cellulose, causing the pH to rise and bacteria to take over. Compost-making has lots of myths! Poorly understood science makes them grow, I suppose. Bokashi composting, for example (more of a fermentation than a composting process) is based on the idea that fermented material decomposes faster, although it’s unclear if this is really true. “The best method of composting is the one that you do and continue to do because you like doing it. Any form of composting is better than taking yard waste to the curb.”
The Rhizosphere chapter is fascinating! Root exudates can restrict the growth of competing roots, attract microbes into symbiotic relationships, Change the chemical and physical properties of the soil solution and the soil, and make nutrients more available. Bacteria make explosive population growth as they feed on exudates. Then their predators, nematodes and protozoa, join the party. The soil water around the roots becomes a nutrient soup. By photosynthesis, the plants produce the attractive exudates that the soil food web turns into plant nutrients right where the roots can efficiently hoover them up. Plants are active in seeking nutrients, not passive recipients. Not to say they have knowledge, or think and plan. It’s a matter of chemical reactions controlled by enzymes with the capacity to change their activity based on the presence or absence of chemical triggers. Let’s marvel at the reality! We don’t need fairy stories!
The second section of the book, Solving Soil Problems, starts with identifying the problems, and works through techniques affecting the soil, chemical and microbe issues, increasing organic matter and structural problems. We are not feeding plants, we are replacing missing nutrients in the soil, so they can take the nutrients they need. The solution will depend on your soil, so a “tomato fertilizer” is not going to be what tomatoes need in every soil. If you plan to top up the missing nutrients, get a soil test to learn what those are. But if you plan to apply manure or compost everywhere as your only amendment, your money is wasted on a soil test. If you add compost every year and return cover crops, organic mulch and your plant debris to the soil, and your plants are mostly growing well, you probably don’t need to add any other fertilizer to your garden. This alarmed me a bit. What about boron shortage, which happens here? Yes, if you are a farmer or market gardener, yields do matter and soil tests (free for commercial growers in Virginia) will be worthwhile. But for a home gardener, or a landscape gardener, yields might not be at the top of your list. Robert explains various tests, and gives his take on how useful they are. The information here can save a lot of confusion and wasted effort.
In the techniques chapter, the author explains the dramatic difference in available nitrogen in a cultivated garden and a no-till one. No-till can supply up to five times the nitrogen, because tilling adds more air into the soil, increasing the microbial activity, burning up the OM. There is a useful chart comparing the effects of fertilizer, compost and wood chips on the soil. We’ve all learned not to bury wood chips in the soil, where they use up the nitrogen while decomposing. But on the surface they can do wonders.
Crop rotation has come under scorn recently from commercial growers who are focused on maximizing yield and profit for their time on small areas of land. Sure, salad mix and baby spinach can rake in the money. But generations of farmers have learned to grow different types of crops each year in a particular spot. This can increase yields 10-25%, even though we are not sure why. Studies have shown it’s not simply nutrient availability. It could be pH changes freeing up more nutrients, or microbe biodiversity, or differing root growth granting access to more depth than the current crop alone can achieve. Rotated crops are more drought resistant and make better use of nitrogen. Research is needed.
As I was happily digesting this book I was brought short by this mnemonic that still puzzles me: “If you have trouble remembering whether P stands for phosphorus or potassium, remember that these nutrients are listed in alphabetical order. Phosphorus comes before potassium in the alphabet, and so P comes before K.” Um, K comes before P, last time I looked. Confusing.
Does rock dust add nutrients? No evidence, says Robert. Do not be beguiled by mineral products claiming to add 74 minerals to your soil. Plants might only use 20 of them. More is not better! Beware fad products such as biostimulants and probiotics. Plants cannot use vitamin B1. What about compost tea? Yes, it adds nutrients, but claims that the included microbes work wonders are not supported by science: test results are very mixed, including worse. Sometimes we are too gullible! Milk, molasses: they add nutrients but no special magic. Fermenting something cannot add nutrients – it could make some more available, although that isn’t proven either. The fungal and bacterial populations increase, but are the species nutritious ones or pathogenic ones?
The gardener’s goal is to farm healthy microbes, even though they are too small to see. Use the state of the soil and the health of the plants as indicators of the health of the microbes. Supply OM, water and you’re on the right track. It has been proved useful to add rhizobium legume inoculant if you haven’t grown legumes for some years. Fungal inoculation of soybeans in low phosphorus soil will be effective. Not otherwise.
The author’s general practice is to improve the soil environment to help existing microbes. There is a list of 7 general ways to do that. There is a whole chapter on increasing OM, using what’s local and cheap. Coir is a waste product, but its production causes environmental damage to local water supplies (large amounts of sodium have to be leached out).
Biochar, one of the new “Garden Wonders”, has claims to make big improvements to the soil food web. Most of the biochar studies have been conducted in labs, not on farms. Even then, 50% of the studies report higher yields, 20% report no change, and 30% report a decrease. There are probably better ways to spend your money!
What about gypsum? I believed the common advice to use it to break up clay soils. Mostly this myth is not supported by evidence. Gypsum can have some negative effects. Add more OM instead. Likewise for improving sandy soils: add more OM.
The final section of the book is a set of worksheets and instructions to help gardeners improve the soil health where they are. This is a slow process, so start soon! Robert has also made the forms available on his website www.gardenfundamentals.com/soil-book-forms. First assess your soil, then make an action plan, then record your progress.
I recommend this book for all sustainable/regenerative/organic gardeners and small-scale farmers, and even large-scale farmers who realize there are gaps in their understanding of soil science. This book is very accessible, user-friendly and full of soil-based common sense. Winter is a good time to make new plans!
PART SIX: Planning to grow potatoes again (September)
I have a whole chapter about potatoes in Sustainable Market Farming, where the basics of potato growing can be found. Below are more details about growing potatoes that you may not have wanted or needed this year. Use your own records and this information to plan for bigger harvests, at times of year suited to your farm.
Some varieties store better than others, so advance planning will help achieve good results. Scrutinize the small print in the seed catalogs before your next seed order.
Potato types: determinate and indeterminate
We have mostly grown Red Pontiac, Yukon Gold and Kennebec. They all seem to be determinate varieties — they grow as a bush, then flower and die. I only learned this year that there are determinate (varieties with naturally self-limiting growth, generally “early” varieties) and indeterminate varieties (such as “Russet Nugget,” “Nicola,” “German Butterball” and “Elba”). The distinction is explained in Potato Bag Gardening. Growers using towers, grow bags, and cage systems want indeterminate potatoes, which continue to produce more layers of tubers on the stems as they are progressively covered with more soil. Growers wanting a fast reliable crop in the field mostly choose determinate types, which grow as a bush, then flower and die. The Internet does seem to have some contradictory statements about which varieties are determinate and which indeterminate, and some dedicated container growers make assertions not supported by experienced commercial growers. So Reader Beware! I trust Extension and here’s a link to their Ask an Expert page on potato types.
Crop rotation, including cover crops
This is very important for potatoes, which are nightshades like potatoes, peppers and eggplant. Colorado potato beetles emerge from the soil in spring and walk (they don’t fly at this stage) towards the nearest nightshades they can detect. Give them a long hike! A distance of 750′ (230 m) or more from last year’s nightshade plots should keep them away. A three- or four-year rotation out of nightshades in each plot is ideal.
Suitable cover crops before potatoes include brassicas (which can help reduce root knot nematodes and Verticillium), Japanese millet (which can reduce Rhizoctonia) and cereals in general. Beware beets, buckwheat and legumes such as red and crimson clovers, and some peas and beans, as these can host Rhizoctonia and scab.
In our ten year crop rotation, our March-planted potatoes follow a winter of oats and soy (which winter-kill in our zone 7a climate). This cover crop is undersown in our late sweet corn about 30 days after sowing. Our June-planted potatoes follow a winter cover crop mix of winter wheat or winter rye and crimson clover. This mix is sown in early-mid October after our middle planting of sweet corn. (Yes, we risk the clover.) We had read that potatoes are said to do well after corn, so when we set up our crop rotation, that’s what we did. I have no scientific proof that the assertion is true, but we often have good potatoes, so at least it does no obvious harm!
After harvesting our March-planted potatoes in mid-July, we regularly did a fast-turnaround and transplanted our fall broccoli and cabbage in late July. We undersowed that with a clover mix 4 weeks after planting the brassicas. We kept the clover mix for an all-year Green Fallow, right round until the February a year and a half later. This fast-turnaround was a bit nerve-wracking, so we no longer do that, simply following the potatoes with the clover mix, while transplanting the brassicas in another plot.
After harvesting our June-planted potatoes in October, we sow winter wheat or winter rye with crimson clover or Austrian Winter Peas, depending when we are ready to sow. (Wheat and clover if by 10/15, rye and peas if later)
Preparing the Soil
Potatoes benefit from generous amounts of compost or other organic matter (they use 10 tons/ac, 22,400 kg/ha) and will grow in soils with a pH of 5.0–6.5. They use high amounts of phosphorus (P) and potassium (K), and need adequate soil levels of iron and manganese. They are less affected by low levels of copper and boron. Hay mulch can be a good source of K. As Carol Deppe points out, potatoes will still produce an OK crop in poor soil, where you might not be able to grow much else. See the ATTRA publication Potatoes: Organic Production and Marketing.
See Part 5, Storing Potatoes, for an introduction to this topic. When potatoes sprout and whether they grow one or more sprouts, can be controlled by manipulating the storage conditions.
For extra-early spring planting, aim to sprout relatively few eyes per potato, so that relatively few shoots will grow and the seed pieces will be big enough, with enough nutrients for the plants. Do this by priming the seed potatoes at 65°F (18°C) until the eyes at the rose end just start to sprout. Store at 45°F (7°C) until two weeks before planting time, then finish the sprouting in warmth and light. The early sprouting of the rose-end eyes suppresses the sprouting of the other eyes. If needed, break off extra sprouts before planting.
To avoid sprouting, keep the potatoes below 50F (10C) once they are more than a month from harvest, avoid excess moisture, and avoid “physiological aging” of the potatoes, caused by stressing them with fluctuating temperatures, among other things. If eating potatoes do start to develop sprouts, it’s a good idea to rub off the sprouts as soon as possible, because the sprouting will produce ethylene, which will encourage more sprouting.
Physiological age of seed potatoes
Seed potatoes can act differently depending on their “physiological age.” The warmer the conditions are after dormancy ends, the quicker the sprouts grow and the faster the tubers “age.” When we buy seed potatoes the storage conditions they have already received are beyond our control. As a guide, the length of the longest sprout, and the number of sprouts are measures of physiological age (if the sprouting has taken place in the light). Varieties do not all show these effects to the same degree.
Deliberately adjusting storage temperatures is a way of manipulating the physiological age, in order to get higher yields or earlier maturity. To age seed potatoes, buy the seed in late fall or early winter before they break dormancy and store them rose (eye) end up in daylight at 50°F (10°C) until just before the planting date. In spring, reduce the temperature just before planting, to minimize the thermal shock from the cold soil.
Physiologically “young” tubers will have just one or two sprouts, due to apical dominance (when the leading bud inhibits the other eyes from developing shoots). The plants will have fewer stems, leading to fewer, but larger, potatoes. They will need longer to grow, and so give a later harvest. If you hurry and dig them early, you will only get low yields.
“Middle-aged” tubers give the best yields (27% higher than young or old tubers). “Middle-aged” seed potatoes have multiple short sprouts, without the hairy look of “old” ones. The pre-sprouting instructions given in Part One:Planting potatoes aim to produce “middle-aged” seed.
Physiologically “old” seed potatoes will have many “hairy-looking” branched sprouts, coming from eyes all over the potato. These potato plants emerge faster and start tuber formation sooner. The final plant size will be smaller (because the shoots are weak) and the plants will be more susceptible to drought and die sooner. Because the tubers do mature quickly, they may be good if you seek an early harvest, or are planting a fall crop a bit too close to the frost date. The total yield will be lower (but earlier) than from “younger” seed.
Root Crops to Plant in Central Virginia in September
In September the days get shorter and we get our last chance to plant crops to feed us during the winter. Much more of our garden time will be spent harvesting this month!
In early September we can direct sow several root crops.
Daikon and other winter radish (in very early September);
Turnips (by 9/15);
Kohlrabi only takes 60 days from sowing to harvest. They can be direct sown or transplanted from flats or an outdoor nursery seedbed at the beginning of September. Kohlrabi is hardy to about 15°F (-9.4°C). Our night temperatures will be higher than that until the beginning of November;
Small radishes by mid-September. We usually squeeze these in on the south shoulder of a bed of kale, because they grow quickly and we don’t need a whole bedful. By the time the kale needs the space, the radishes will be gone.
In the hoophouse, we start our winter crops by sowing radishes and leafy greens on 9/6 or 9/7.
It’s too late for any slow-growing crops like carrots. We can just squeeze in some beets at the beginning of September, if we take good care of them. Hoeing, weeding and thinning at the first opportunity will help them grow a bit faster and make up for lost time. We could cover them with rowcover to warm their airspace and soil, once we have got them established and tidied up. I hate to cover weedy crops with rowcover – you just know it encourages weeds to grow faster! Beets won’t die of cold until 12F for my favorite, Cylindra, so they have quite a while yet. See Root Crops in August for more about fall beets.
Radish succession crops
In our winter hoophouse, we sow radishes six or seven times. It is a science and an art to time the sowings to provide a succession of delectable little radishes with no gaps in supply and no overlap of plantings and gnarly big roots. I have made a graph of radish sowing and harvesting dates to help us even out our supply.
Here’s a chart. 1/25 is our last worthwhile sowing date for hoophouse radishes.
Harvest 10/5 – 11/15
Harvest 11/6 – 12/25
Harvest 12/16 – 2/7
Harvest 1/16 – 2/25
Harvest 2/19 – 3/16
Root Crops to Harvest in Central Virginia in September
During September, the root crops we can harvest include beets (and beet greens), carrots, radishes, turnips and horseradish (which I have more to say about below). We hold off on parsnips, if we have grown those, as the flavor improves a lot after a frost.
We could harvest potatoes, which I have written about in Potato Harvesting and Root Crops in June. We hold off on sweet potatoes until October, and I’ll write about them in a post of their own in a few weeks. If you need to harvest earlier, read the chapter in Sustainable Market Farming.
Special Root Crop Topic for September in Central Virginia: Horseradish
Horseradish, Armoracia rusticana, a perennial, is very easily propagated from pieces of root. It can be hard to get rid of if you change your mind! It’s wise to plant your perennial food crops in a special place that isn’t part of your annual crop rotation space. Remove all perennial weeds before planting horseradish or any other perennial vegetable. Ours is beside our grape vines, near our rhubarb. Full sun or partial shade will work. Horseradish looks like a big bad dock growing, but is in fact a brassica. Horseradish can provide value-added products for out-of-season sales, as well as a pungent treat in cold weather.
Buy or beg crowns or root pieces, and plant them 4-6 weeks before your average last frost date. Horseradish grows best in cool, damp regions with temperatures between 45°F (7°C) and 75°F (24°C). But in central Virginia, temperatures go from 0°F (-18°C) and 100°F (38°C) and we have more than enough horseradish, so don’t worry too much about that temperature range.
Plant crowns just at soil level. Plant root pieces with the top just below the surface and the bottom end covered with 2-3’ (5-8 cm) of soil. Space horseradish plants 24-36” (60-90 cm) apart. If you are worried about it spreading into important nearby plants, create a metal, wood or stone barrier 24” (60 cm) deep around the bed.
Keep the soil damp, add some compost once a year. You are unlikely to have any pest or disease problems with this crop. Young plants should not be harvested until the leaves are at least 12” (30 cm) long.
Horseradish is traditionally harvested September-April (the months with R in them!). The roots go as much as 2 ft (60 cm) deep and are very strong (but not as sturdy as gobo, Chinese burdock). Use a strong shovel, spade or digging fork, and start loosening the roots from 6” (15 cm) away. If you hear or feel a root snap, be glad! The goal is to extract some of the roots and firm up whatever remains, to continue growing. Water the plants after harvest if the weather is dry.
Collect the harvested root parts in a bucket, and wash them right away. You can store them dirty, but it is harder to get them clean later. Harvested roots can be refrigerated for several months until used – they seem fairly impervious to rot.
When you process horseradish do it outdoors, with googles on. I kid you not! This can be a good porch activity in sunny chilly weather. After thoroughly washing and scrubbing the roots, peel them carefully. Throw the peelings in the trash, not the compost pile, as they easily regrow from tiny pieces!
The peeled roots can be ground up in a food processor, to make relish or sauce. Or if you prefer, use a fine grater.
If you’d like to read more about horseradish, including container plants grown as an annual, there’s info on Harvest to Table
If you’d like to read how to make the condiment, see Barbara Pleasant’s article on GrowVeg
Other Root Crop Tasksin Central Virginia in September: Washing, sorting and storing root crops
How you harvest roots depends on the scale of your farm and the equipment you have. For example, with carrots, you can mow or tear off the tops, then undercut with machinery, then lift. Or you can use the tops to help get the carrots out of ground, as we do, loosening them with a digging fork, then trim.
Ensure gentle treatment and no bruising of roots while harvesting. As we all know, it is important to avoid bacterial contamination. Wounds and abrasions can lead the crop to pick up new bacteria from the environment. Crops can be punctured by sharp edges of containers as well as the more obvious knives and fingernails.
Our method is to bring the harvested roots to a shady spot to trim, wash, sort and bag. We have a printed sheet, optimistically called “Perfect Vegetable Storage” to help us remember from year to year the tips we have learned. Usually we need scissors or knives for a clean cut, and usually we aim to leave about ¼” (0.5 cm) of leaf-stems attached to roots. It might be quicker to tear the leaves off, but this doesn’t give such good results and can cause the crop to need extra storage space. When we harvest carrots for immediate use, we snap the tops off right at the junction of the foliage and the root. When we harvest for storage, we trim with scissors to leave a small length of greens.
Washing and rinsing
After washing, and perhaps before, comes cooling. Make full use of all possibilities, such as damp burlap, or high percentage shade cloth, or the shade of trees, buildings, or a truck. At the washing station, crops may be sprayed down on a mesh table, or dunked in troughs or buckets of clean water. Washing can also act to cool the crop.
Draining away the water is important. Drain on a mesh table or in a holey bucket, a suspended mesh bag or laundry basket. Barrel root washers have the draining stage built in. We don’t have a rotary barrel root washer, much as we’d like one. Here’s our manual method.
As you cut, gently drop the roots into buckets of water. This lets the dirt wash itself off to some extent, as you continue to cut more. Use whatever size and type of container seems most efficient.
When the wash container is full, switch from trimming to washing: rub each root with your hands and drop it gently into a container of clean rinse water. Depending on the cleanliness of the roots after washing, it may be possible to reuse the rinse water. Or else make it be wash water for the next round. Once the water is quite dirty it needs to go. Gently pour it round a tree, or on the ground somewhere else. Avoid causing a washout by flinging a bucketful all in one place. Rinsing needs pretty clean water.
When the rinse container is full, get two clean holey buckets. Take the roots one at a time out of the rinse water (don’t rub then any more, just lift them out). Sort as you go.
Sorting storable roots from non-storable
Decide if the root is Storable or is Use First (cull, or home use). Storable are sound, reasonably large. Use First may be small (less than ¾” diameter, less than 3” long, maybe) or damaged (deep holes, soft spots, fresh complex cracks). Open dry cracks or snapped-in-half roots may heal over and store just fine.
We made different sized holes in a special bucket lid, to help new people get an idea of size.
Put the storable ones in one holey bucket and the non-storable (Use First) in the other. It helps to have 2 different colored buckets. It’s better to err on the side of calling doubtful ones Use First, but it’s even better to learn good sorting, as too many Use First roots can’t all be used quickly.
When a Use First bucket is full, set it aside, or put on the cart or truck. Once a Storable bucket is full, set it aside to drain thoroughly before bagging. Do not confuse categories. Do more trimming, washing, rinsing, sorting.
When the Storable roots have drained, get a well-perforated plastic sack. Ensure there are enough holes and big enough ones. Buy perforated bags or perforate your own. If you need more holes, the safest method is to lay the bag on the grass, stand on diagonally opposite corners, then stab the bag with a largish knife. Make about 3 cuts across the width of the bag and about 6? 7? 8? down the length. Or fold the bag and use a 3-ring paper hole punch in several places. Refold and repeat.
Gently pour the Storable roots into the well-perforated bag. We usually use 50 pound bags. Tie the neck with a short length of rope and make a masking tape “flag” label with the date and the type of vegetable.
When all the bags of storers have been gathered up, record the number going to the cooler on an Inventory clipboard. If there is no official tally sheet, make one on a full size sheet of paper.
We store bulk roots in a walk-in cooler, up on a high loft/shelf. Use pallets in the loft for better airflow under the bags. Start a new pallet for each different type of vegetable and for a substantially different date, eg fall carrots separate from spring carrots. Keep inventory: once a month, someone takes stock of what we have and updates the list.
Book Review: Dispossession: Discrimination against African American Farmers in the Age of Civil Rights
by Pete Daniel, University of North Carolina Press, 2015. 352 pages, with 17 photos, $29.95.
Dispossession is a very gripping and valuable book, a combination of detailed history and personal stories, making plain how African American farmers were systematically deprived of their land and livelihood by the white-controlled agri-government during the third quarter of the twentieth century. Yes, the same “civil rights era” when some substantial success was made against racial discrimination. At that same time, agriculture was experiencing big changes leading to increased yields. Mechanization, herbicides and pesticides reduced the number of farmworkers needed. Between 1940 and 1974, the number of African American farmers fell by an astounding 93 percent, compared with a much smaller number of white farmers leaving the land. The magnitude of this decline was personal tragedy to those farmers and it was not coincidental – white people in the USDA manipulated the distribution of information, loans, grants and of positions of power, to favor white farmers. This shameful part of American history only slowly became apparent to me, a white immigrant farmer, as I noticed USDA reparation efforts within phrases like “historically under-served”. Quite the under-statement!
The USDA promoted capital-intensive agriculture and subsidized already wealthy farmers headed in this direction. At the same time, the USDA put barriers in the way of women and minority farmers seeking a fair share of resources, including the important acreage allotments (approval to grow certain acreages of wheat, cotton, corn, tobacco, peanuts, and rice). These production controls had been introduced in the mid-1950s to prevent surplus production. Every couple of years the rules changed, and not all farmers were given the needed information to apply for that year’s permits and price support mechanisms.
The USDA had been run by white men since it was formed in 1862, and, with the exception of the Negro Extension Service, African Americans were excluded from any decision-making positions. Many individuals and organizations worked to get USDA to remove the discrimination, and to help African Americans get a fair distribution of the resources. Pete Daniel’s book focuses on the South in the years before the 1999 Pigford v. Glickman class action suit, which won compensation for discrimination occurring after 1981. Previously there was no real check on USDA discrimination. The class action suit opened the way for similar suits by women, Native Americans and Latinx farmers.
The first couple of chapters of the book give the overview and make for information-packed reading. After setting the stage, Pete Daniel shares individual stories of farmers, civil rights volunteers, and black extension agents. The first chapter is called “Intended Consequences”. Although the 1964 Civil Rights Act banned discrimination, the US Commission on Civil Rights (created to monitor the application of the Act) reported in March 1965 of a broad range of discriminatory practices in every office of the USDA. It took 30 years before Timothy Pigford brought the suit that found the USDA guilty of widespread discrimination. The broken promise of “Forty acres and a mule” for every soldier in the Civil War was followed by decades of subverted laws and farming programs that left black farmers unjustly treated. And Pigford did not fix everything! Congress did not make funds available until 2010, by which time many of the mistreated farmers had died or lost their farms. And all the farmers discriminated against before 1981 received no recompense.
At the very time that laws were supposedly protecting Black people from bias, Black farmers were suffering the most crippling discrimination. It was very hard for sharecroppers to become tenant farmers, with control over the sale of their own crops. Their fortunes were eroded by labor laws, bad weather, bankers, landlords and pests. Diets were poor, and so was sanitation and health, as well as childhood schooling. Many tenants and sharecroppers became redundant as machinery took their jobs.
Black farmers who succeeded did so by cultivating white support, as advised by Booker T Washington. The decline of Black farmers after World War II was in strong contrast with their gains in the 50 years after Emancipation from slavery. Over-production led to lower prices, which led to desperate farmers.
The USDA was founded during the Civil War to encourage better farming methods throughout the country. In 1862, Congress funded land-grant universities in each state. Since Southern white schools would not admit Black students, Congress funded the African American land grant colleges in 1890 (with fewer resources than went to the white colleges).
The 1887 Hatch Act established agricultural research stations, and Congress established the segregated and unequal Federal Extension Service in 1914, operating out of the land-grant universities, providing some farmers with advice and information. The organization of the Extension Service was convoluted, territorial and discriminatory, and extension agents wielded enormous power. The confused structure lead to claims that some agents were employed by the county and some were federal employees. (All, in fact, were part of the federal civil service retirement system and held civil service appointments.)
White agents oversaw the Negro Extension Service, which was hosted by the 1890 land-grant colleges. Black agents got lower pay and poorer equipment, but the jobs offered respectability and the opportunity to serve rural people. Women working for the Home Demonstration service got a lot of satisfaction from the work. African American Extension agents had to tread a fine line when addressing the needs of Black famers and preserving goodwill with whites. Many whites only tolerated black agents who did not challenge their authority or disrupt farm labor.
A white agent with 6 years’ work experience with the extension service was paid $375 a month, while a black agent with 14 years’ experience was paid only $212. The Black agent received considerably less information from the office, and was kept out of the decision-making loop. In some places, the furniture for the Black agent’s office was much poorer quality than that in the white agent’s office; Black agents received no vehicles, and little demonstration materials and had to do their own typing. Black agents were usually isolated from decision-making and rarely interacted with their white counterparts. Because the USDA functioned in isolation, the white leadership in USDA had not been challenged about their discriminatory practices.
Loans often went to wealthier farmers rather than the poor farmers for whom the program was intended. Black farmers assumed many of the programs were for whites only, and did not apply. Or they decided that the costs of upsetting the applecart were higher than the costs of managing without those resources. As pressure mounted on the agricultural organizations to appoint or elect African Americans, whites turned to intimidation, tokenism and duplicity, such as getting permission to include the name of an African American on a committee, but then not telling the person which committee or when they met. His name was sought to satisfy requirements, but his participation was not wanted.
During early 1964, the Student Nonviolent Coordinating Committee was preparing for the Freedom Summer, and the US Commission on Civil Rights turned its attention to the USDA. This 6-person commission made investigations and reports but had no enforcement power. The National Sharecroppers Fund had filed nine discrimination cases with the Secretary of Agriculture, Orville Freeman, but Freeman had reported that all Mississippi USDA agencies had denied discrimination, as if that was a fact. The commission interviewers questioned USDA agents throughout the South, and observed unchallenged malpractice in powerful southern USDA county offices. Black farmers had not received information about new trends or programs or loans. Black farmers often received no notices of conservation service or other committee elections, or even of their right to vote.
Successful Black farmers made their own way, finding sources of loans outside pf the government agencies that should have helped them. Many Black farmers had no idea they even had access to USDA. Many USDA committees throughout the South controlled which farmers received information. Acreage allotment increases went to the “committeemen. White land-grant universities paid lip service to the support of civil rights, but distributed the resources as they liked.
Towards the end of the Freedom Summer of 1964, civil rights activists moved into helping African Americans benefit from federal programs. They also hoped to get Black farmers onto committees where they could have influence by force of numbers. Many believed the jobs were for whites only. Sharecroppers and tenant farmers were squeezed out when committee work involved calculations they had never been taught to do, or understanding complex farm programs.
This left the field open for white agents to ignore deceitful acreage measurements by white farmers. Surpluses were not destroyed, even in cases where they were hundreds of acres in excess. Some ballot boxes were stuffed, some elections were declared invalid. In order to preserve central control and shore up apparent participation, committee members sometimes convinced farmers of the value of programs that did not help them.
Court jurisdiction in disputes was replaced by powerful committees that were not neutral, and did not rely on established precedent. Farmers were at the mercy of the personal preferences of the committeemen.
SNCC workers saw how sharecroppers did not have access to their accounts, and Willie Mae Robinson in Mississippi, for example, picked 20 bales of cotton in 1962, that should have brought her $1870. But she was only given $3.
In 1963, when Martin Luther King Jr gave his “I Have a Dream” speech at the March on Washington, civil rights leaders there urged John Lewis, the SNCC chair, to tone down his criticism of the Kennedy administration for unlawful arrests and failure to promote the civil rights bill. SNCC was seen as outside the main campaign for civil rights. When farmers in Mississippi provided housing for the SNCC workers, they suffered economic reprisals. When they registered to vote, they risked losing their homes and their jobs. Sharecroppers had no bargaining chips. One key for progress was to get Black farmers to stand for seats on the Conservation Service committees.
In 1965, The Conservation Service (ASCS) took steps to make sure all farmers had the chance to vote, and that the elections would be fair. But there was widespread fraud and intimidation, which the Conservation Service chose to ignore. Sometimes Black farmers found their names had been added to the ballot in an effort to dilute Black votes, preventing any African American farmers getting seats on the committee. Or ballots included only Black nominees chosen by white committees for their cooperation with whites rather than their support of Black farmers. “Discouragement” and humiliating treatment of this sort was widespread. Black farm wives in one county had been required to collect their own ballot slips at the office instead of receiving them in the mail like everyone else. Whites exacted a price for Black activism, such as registering to vote. Physical intimidation and violence, firing from jobs, and petty insults, such as using only first names for Black people, were common.
All-black advisory committees were set up to assist white ASCS committees, although this was not the equal participation mandated for federal programs. Unsurprisingly, white committees continued to run the show. SNCC workers offered workshops and stressed how important participation in ASCS elections was. They gave support by putting opaque election rules into plain English, and using stick-figure diagrams to explain elections, so farmers could understand what options they had.
The next year, Horace Godfrey, the head of ASCS, ordered counties to hire non-whites for temporary summer jobs at the same percentage of the population as whites. This was challenging in high-majority Black counties, and with few Black farmers owning cars. Also, the numbers of Black farmers were declining, leaving whites more control. However, overall, Godfrey’s hiring initiative became the best civil rights action taken by any USDA administrator in the 1960s. This did not smoothly lead to the hiring of more Black farmers for permanent jobs, although the ASCS set up a training program for clerical positions, which helped a few individuals each year and cracked the segregation within ASCS.
1965 included an escalation of violence, with the assassination of Malcolm X, the police brutality towards the marchers in Selma, President Johnson’s increase of troops in the Vietnam War, and the introduction of the draft. Press attention turned towards the war and away from civil rights.
In July 1965, Nyle Brady (the soil scientist), as the USDA’s director of science and education, claimed that the Extension Service had contacted 312,000 non-white southern farmers. Census numbers showed that there were less than 200,000 nonwhite farmers in the South.
Many elections were rigged, but Washington refused to take corrective action, or even admit anything was wrong. In July 1966 in Lowndes County, Alabama there was such blatant fraud that Stokely Carmichael reflected “If the government can spend billions of dollars to kill people in Vietnam to assure free elections, then they had better spend some of those dollars to assure free elections in the Lowndes County ASCS.” Stokely Carmichael led SNCC away from civil rights organizations including their white allies and focused more on color rather than class. He introduced the Black Power slogan, which meant different things to different people, perhaps as “Defund the Police” does in our times. His belligerent words alienated John Lewis, Charles Sherrod and Julian Bond, who all resigned from SNCC in 1966.The last of the white allies left in the spring of 1967, a step that was painful to many of them. The representation of Black farmers on ASCS suffered as a result of this pivot of attention in the SNCC.
During 1968, support from civil rights workers for southern Black farmers dwindled as political activists focused on anti-war efforts. Increasingly, the focus of discrimination included women, who were extremely rare within USDA. In a summary of minorities on county committees, there were no women at all. Beginning to employ Black people and white women changed the office culture. Training programs began for minorities (and women?), to qualify them for jobs in ASCS.
Integrating 4H camps proved too challenging for some white extension administrators, who cancelled the whole program rather than integrate. I am reminded of the closing of the white public swimming pool in one county in Virginia, by those in power, who would not integrate. The county remained without a public swimming pool for decades.
In 1981, the USDA had disbanded its Office of Civil Rights and stopped responding to farmers who had filed complaints. The US Commission on Civil Rights reported in 1982 on continued injustice in every program, which resembled too much the discrimination exposed in its 1965 report. By 1982 only 33,000 Black farmers remained in the South. Isidoro Rodriguez headed the Office of Minority Affairs from 1981, and in a bid to support the Republicans, dropped civil rights guidelines that were contrary to the Reagan administration. Investigations dropped from 90 a year to zero. He cut staff by ten and returned $475,000 in unspent funds. He was fired in 1983.
The 1984 House Judiciary Subcommittee hearing included as a witness, Timothy Pigford, who went on to file a class action suit, after eight years of struggling to afford to farm in the teeth of very bad advice and no financial assistance from the USDA. The 1999 Pigford v. Glickman class action suit won compensation for discrimination occurring after 1981 claims of discrimination. (The two-year statute of limitations was extended to cover the longer period.) Theoretically, before that date, the office of Civil Rights had dealt with complaints, although as we have seen, this was a big whitewash.
As a result of Pigford, farmers lacking incomplete documentation of their claim could get a cash payment of $50,000 and forgiveness of debts owed to the USDA. Farmers with documentation had no cap on what they could recover. Judge Friedman commented that the billions of dollars due to farmers for discrimination would show that the USDA was not above the law and remind them of the consequences of discrimination.
The payment of compensation resulting from Pigford claims was delayed in some cases for a decade, until February 2010 when the Obama administration announced a $1.25 billion settlement with African American farmers.
Memory fades and the history of the civil rights movement is mythologized as a string of heroes, achievements and successes. Like the earlier faked compliance reports, the success story has edited out conflicts, obstruction of justice and the many individual and small group efforts to bring justice. The USDA spoke of equal opportunity even as it obscured inequities in lending and provision of information and assistance and discriminated in choosing employees, and as it continued bad policies that drove more African American farmers off the land. Resources went to relatively wealthy white farmers
To compound the problems of Black farmers, many died without making a will, and all the heirs inherited the farm. Any heir could later sell their share outside the family to someone who could force a partition sale. Problems with Heirs’ Property caused a further loss of farming land in the African American community.
In July 1987 only 33 of 2,520 county directors in the nation were Black. Most of the offices by then were staffed by white women. All the Good Old Boys were resisting having a Black man in charge.
After Pigford, the USDA did backslide, and in 2009, Tom Vilsack as the incoming Secretary of Agriculture, inherited 11,000 unprocessed civil rights complaints, several class action suits and 113,000 employee discrimination complaints. In November 1999, Native American farmers had filed a suit that led to a $760million fund to pay damages, as well as cancelled debts. Hispanics sued in 2000. Women sued and were added to the Hispanic farmers’ case. These cases opened the way for more claims from other minorities who had suffered discrimination.
Lloyd Wright, former chief of civil rights under President Bill Clinton—and himself a farmer—on his family farm in Montross, Virginia. Photo Donnamaria Jones
No financial settlement makes up for humiliation, distress and loss, and many of these farmers had already lost their land by the time they received money. It is past time we treated everyone with decency and justice.
Click the link for an interview with Pete Daniel and Jess Gilbert on Edge Effects
Heads up everyone saving seed from their tomatoes, melons, or squash this year, in anticipation of possible seed shortages next spring! Or because you have the time at home to figure out how to do it, and you’re around to stir the bucket three times a day! I have an article on wet seed processing in the August issue of Growing for Market magazine.
The next issue will have my article on dry seed processing (think beans, peas, okra, lettuce).
The current issue also has a couple of interesting articles on how to move step-by-step towards no-till growing, or at least minimum-till. Many gardeners and farmers have floundered while making this transition, so learn from the experienced! And there’s an article by Julia Shanks on balance sheets, for those intending to make a living farming.
Or choose the 2020 all-access course bundle of 21 courses (over 100 videos) for $150.
Or before summer is over, go for the $120, 8 course (56 videos) Summer Bundle.
What went wrong with our hoophouse peppers in 2020?
Our 2020 hoophouse peppers were stunted, crinkled, yellowing and failed to thrive.
Too cold in edge bed A (drafts under baseboard)?
Too wet in bed A (rainwater under baseboard, not much drying out due to shade of tomatoes)?
Nutsedge poisoning: roots exude something that inhibits other plants?
Soil too salty?
Soil nutrients poor?
Aphids spread a virus? (plants were crinkled)
Are we sowing hoophouse peppers too early? In cells that are too big?
Are we transplanting hoophouse peppers too early? Keeping them in in cells that are too small?
Be sure to block drafts all winter. Try not to plant peppers in cold edge beds.
Close one row of driptape if soil in edge bed A seems excessively wet compared to other beds. Re-dig outside moat to keep soil water out.
Do better about weeding out nutsedge. Investigate soil properties that encourage nutsedge.
Use beds C and E instead of middle bed D when doing salt water wash down. Poke out holes in sprinkler, ensure all are working. Get a better sprinkler.
Do soil tests in October and remediate soil as needed.
We could monitor for pests and act promptly
Deal with aphids and avoid viral diseases
Sow later, in smaller cells.
Transplant later, after potting up to bigger cells or pots.
Summary of ideas after our meeting and reading 2020 records:
Use fresh seed
Go back to deep 6 cells for sowing, (smaller than R38)
Use more appropriately warm growing conditions. Peppers don’t recover well from setbacks. They remain stunted long term.
Test soil and act accordingly.
Ensure salt wash-down reaches the edge beds.
If planting in chilly edge beds, ensure the baseboards are not drafty.
Remove nutsedge whenever we see it
Monitor for pests; deal with aphids to avoid long-term virus diseases.
Hoophouse Pepper Records Research
We have been sowing 2/3 for a 4/7 transplant date. That’s maybe too long. 9 weeks.
2/3/20 Hphs peppers sown as scheduled. Used R38s rather than usual deep 6s. It’s recommended not to sow peppers in large cells – they are slow growing, and it’s hard to get the watering right in large cells.
2/11 -2/14 Peppers germinated. We had some trouble with keeping the germinating chambers up to temperature because we didn’t have the right lightbulbs.
2/15 – 2/17 Heat mats not all plugged in or working right.
2/21 resowed Gilboa. PeaceWork was old seed, poor vigor? Or low germ rate?
2/28 Gilboa resows had been in tent but weren’t actually germinated. Back in fridge.
3/4 – 3/9 Potted up. Is this true? R38s don’t normally get potted up. Maybe due to patchy germination?
3/16 In ghs drafty zone
4/5 Ghs door left open all night
4/12 Ghs door left open all night again.
Info from Sustainable Market Farming and The Year-Round Hoophouse
Sow 8-10 weeks before you intend to transplant.
We used to sow our hoophouse peppers 1/17, then 1/24, then 1/31, then 2/3.
Minimum temperature for germination is 60F, optimum 68-95F.
Peppers seem to produce stockier plants if soil temperatures are 65-68F, max 80F daytime, min 60F at night after germination. Use a soil thermometer.
Transplants getting slightly cooler nights will grow sturdier plants that flower later and have more potential for big yields. Rowcover at night if 40F or below.
After third true leaf, can reduce night temp to 54F. May increase yields.
But, permanently stunted by conditions that are too cold.
Keeping them in pots or cells that are too small will set them back. If transplanting is delayed, pot up to larger size, eg tomato pots.
Pot up when a few true leaves appear. After that no heat mat needed.
We moved our transplanting date from 4/1 to 4/7 (one week after tomatoes is usual)
Transplant at 6-9 weeks, with 4 or 5 true leaves, not yet flowering. OK if they are big.
Soil for transplanting should be at least 60F, ideally 68F
Avoid transplant shock. Soil needs to be damp before, during and after transplanting. Avoid root damage or bending. Shade if hot, sunny or breezy.
For the first week after transplanting, keep warm.
Established peppers benefit from 70-75F days, 64-68F nights
Maintain sufficient levels of boron, calcium, phosphorus.
Monitor and control aphids and thrips to prevent the diseases they vector.
An inch of water per week is about right.
Foliar feeding with fish or seaweed emulsion once a week after fruit set.
65-80 days from transplant to full-size immature fruits, and another 2-4 weeks to ripe fruit.
Yields should be 5-18 lbs/10ft.
Ideas after rereading those sources
We might do better to set the sowing date a week later (2/10), keep the transplant date at 4/7 and aim for an 8 week-old transplant? (Avoid colder conditions)
We need to pay more attention to temperatures of germination, seedlings and potted transplants. Write the goal temperatures on the Seedlings Schedule
We need to pay more attention to not overwatering seedlings. Write that on the Seedlings Schedule too.
PART SIX: Planning to grow potatoes again (September)
I have a whole chapter about potatoes in my book, Sustainable Market Farming, and another on root cellars (including construction), where much of this information can be found.
This year’s new Victory Gardeners now need to learn how to store your harvest, so it can supply your household for as long a s possible. As more commercial growers aim to produce local food sustainably year-round, the storage of vegetables for sale over the winter becomes important. Understanding the needs of different crops can help reduce your electricity bill and carbon footprint, and maximize the amount of produce you can store for later sale. Only critical crops need refrigeration. Potatoes should not be refrigerated. Many others may be stored without electricity, perhaps in buildings that serve other uses at the height of the growing season.
Don’t expect a one-shed-fits-all solution to crop storage. I identify five different sets of storage requirements, for different storage crops. This one is specific to potatoes, which don’t want colder conditions: Cool and moist: 40°F–50°F (5°C–10°C), 85%–90% humidity. With a good in-ground root cellar, potatoes can be stored for 5-8 months, but other options can also work. A max-min thermometer will help you keep the storage space in the right range.
Only store sound potatoes. Garbage in, garbage out. Damaged and poor quality vegetables will not store well. Always handle all crops for long-term storage gently, to avoid bruising. For long-term storage, make sure crops are fully mature but not over-mature when you harvest. Potatoes need firm skins that don’t rub off when you rub with a thumb. This is different from some crops, such as beets and sweet potatoes, that don’t have a “ripe” stage, but are ready when they reach the size you like. Very small vegetables don’t store well. Expect that a small percentage of your crops will go bad in storage — it’s not a sign of failure, just a reminder that life has limitations.
Cure, then store
Potatoes are one of those vegetables that need to cure before storage in conditions that are different from those needed for storage. Curing allows skins to harden and some of the starches to convert to sugars. See the post on Harvesting Potatoes in July. Potatoes need curing in moist air (90% humidity) for one to two weeks at 60°F–75°F (15°C–24°C). You may be surprised at how warm this is. Wounds in the skin will not heal below 50°F (10°C).
We sort our potatoes after two weeks of curing and find this usually reduces the chance of rot so that we don’t need to sort again. With potatoes, the rate of deterioration drops right down after a few weeks. Remember to keep white potatoes in the dark while curing as well as during storage.
Preparation for storage
Plan your storage sites, buy a thermometer for each site, and gather suitable containers. Clean and prepare your storage space before going out to do a big harvest. Wood crates are good for nostalgia and agritourism, but plastic is kinder on aging backs and less likely to harbor diseases. Containers should rest on shelves, pallets or blocks of some kind, and not be set on bare concrete floors. This helps improve ventilation and reduce condensation.
For traditional storage without refrigeration, potatoes (and most other root crops) store best unwashed (less wrinkling), though this can make them harder to clean later. If you might not be able to keep temperatures low enough, choose stackable crates rather than closed bags. When you have choice in the matter, try to harvest potatoes from relatively dry soil, so they are less likely to grow mold. The packing of your containers should allow for airflow, but you don’t want the produce to shrivel up, so be observant. Sometimes night ventilation offers cooler, drier air than you can get in the daytime. Keeping root cellar temperatures within a narrow range takes human intervention, or sophisticated thermostats and vents. If needed, electric fans can be used to force air through a building.
Ethylene is an odorless, colorless gas, generally associated with ripening, sprouting and rotting. Chilling, wounding and pathogen attack can all induce ethylene formation in damaged crops.
Some crops, including most cut greens, are not very sensitive to ethylene and so can be stored in the same space as ethylene-producing crops. Potatoes are very sensitive to ethylene and will sprout in a high-ethylene environment.
Some crops, such as ripening fruits, produce ethylene gas while in storage. Don’t be tempted to set that bargain box of very ripe bananas you bought on the way home near anything you don’t want to sprout or ripen further. Propane heaters and combustion engines produce ethylene. Be careful if using your garage to store potatoes.
Basement storage rooms and root cellars
Traditional root cellars are made by excavating a large hole near the house, lining it with block or stone-work walls, casting a well-supported and well-insulated concrete roof, then covering the top with a big mound of soil. The doorway may have bulkhead doors or an entry way with additional doors. The more modern version is to construct an insulated cellar in the basement of a building such as a CSA distribution barn or your house. See the Bubels’ book, or the Washington State publication for drawings and instructions on making these. Provide wide doorways with ground-level access if possible (roll that garden cart right in!). Good lighting and drainage are important, so you can see if everything is storing well, or hose the shelves and floor down if it isn’t. Mouse-proofing is worth considering upfront. Our 10’ x 11.5’ (3 x 3.5 m) cellar will hold 360 crates with an ample central path. That’s 10,800 pounds (4900 kg), or around 5 tons (tonnes).
Root Cellar Ecosystem
Store potatoes in a moist, completely dark cellar, ideally at 40°F (5°C), up to 50°F (10°C). Ventilate as needed during times of cool temperatures, to maintain the cellar in the ideal range. We need to actively manage conditions in our root cellar to cure the potatoes and help them store well. We have no automated ventilation, or even ventilation ducts. We simply leave the door open at night when we want to cool it down, or in the daytime in winter. We just choose a time when the forecast temperature is in the range we’re aiming for. Yes, mice do come in the open door! We encourage black snakes to live in our cellar, to keep the mice under control. (How do we encourage snakes? I mean we don’t drive them out, and if we need to, we move one or two in there.) This can be a bit unnerving, as the cellar is dark. (We chose not to have a light, as leaving it on by accident could cause a lot of potato greening before we noticed our mistake.) We have developed a special door-opening technique so we can co-exist with the snakes, who like to hang out on the top of the doorframe. We unlatch the door, open it a crack, then bang it closed, before opening it fully. Any resting snakes have by then dropped to the floor where we can see them and avoid them. (No snakes have been hurt in this process!) People who don’t like snakes will be really motivated to fit a rodent-proof vent system!
I wrote a blog post about Root cellar potato storage, on 8/07/2018. It includes a fuller version of our Root Cellar Warden instructions below. Here is the shorter, post-harvest version of our “Root Cellar Warden” instructions:
After the potato harvest, the potatoes need to be at 60-75F (15-24C) with good ventilation for two weeks. Leave the door open on mild nights (or days) every 2 or 3 days, and close it later. The newly harvested potato is still respiring and needs fresh air. Lack of sufficient oxygen during curing results in Black Heart, a condition where the tubers develop nasty black lumps of dead tissue in the centers, so be sure to provide good ventilation during curing.
After 14 days, the potatoes need sorting to remove Use First and Compost ones. Usually this is done by bringing the crates outdoors. You will need buckets, rags, gloves. It’s important to do this in the 3rd week after harvest, and not leave it longer, to minimize the spread of rot. Keep the crates away from walls, which sometimes collect condensation. The potatoes benefit from the airflow if they are not touching the walls.
After 14 days, cool the cellar whenever a mild night or chilly day is forecast, down to 40-45F (4.5-7C).
Dormancy Requirements of Potatoes
We researched the dormancy requirements of potatoes in an effort to store ours so they don’t sprout when we don’t want them to.
What I know so far about dormancy is that potatoes need a dormancy period of 4-8 weeks after harvest before they will sprout. So if you plan to dig up an early crop and immediately replant some of the potatoes for a later crop, take this into account. Get around this problem by refrigerating them for 16 days, then chitting them in the light for 2 weeks. The company of apples, bananas or onions will help them sprout by emitting ethylene.
To avoid sprouting, keep the potatoes below 50F (10C) once they are more than a month from harvest, avoid excess moisture, and avoid “physiological aging” of the potatoes, caused by stressing them with fluctuating temperatures, among other things. If eating potatoes do start to develop sprouts, it’s a good idea to rub off the sprouts as soon as possible, because the sprouting process affects the flavor, making them sweet in the same way that low temperatures do.
Mary Jo Frazier and colleagues at the University of Idaho Extension, in 2004, researched the use of essential oils of mint and cloves to inhibit sprouting in storage. These plant oils can add 20-30 days storage, and then need to be reapplied. There is the issue of flavors carrying over into the tubers.
Other biocontrols to reduce storage losses
There has been some USDA ARS (Agricultural Research Service) research into biological disease control for stored fruit and vegetables. It takes three directions:
Using biologicals such as Aspire yeast, Bio-Save Bacteria (Pseudomonas syringae) or chitins to form a semi-permeable film over the surface of the roots and fruits;
UV light to induce rot resistance. Primarily used for fruit;
Natural fungicides derived from jasmine and peaches, which induce disease resistance in the crop itself.
Currently these methods are only used by large operations, but in the future, they may be useful to small growers.