What Makes Potatoes Sprout?

Harvesting potatoes. Photo Lori Katz

“White” or Peruvian potatoes (sometimes called Irish potatoes) are stem tubers in the nightshade family; sweet potatoes are root tubers in the Morning Glory family. This article is about Peruvian potatoes, not sweet potatoes.

Curing potatoes

Potatoes are cured enough for storage when the skins don’t rub off. It’s best to leave the potatoes in the ground for two weeks after the tops die, whether naturally or because of mowing, if you want them to store. When the potatoes are harvested after the skins have toughened, there will be less damage during harvest. Curing allows skins to harden and some of the starches to convert to sugars. These changes help the tubers to store for months.

When potatoes first go into storage, they are still “alive” and respiring, and need fresh air frequently. They will heat up if left closed in, and could develop black centers, where the cells die from lack of oxygen.

Storing newly harvested potatoes

For the first two weeks after harvest, the root cellar or other storage space will need 6-9 hours of ventilation every two or three days. The temperature goal is 60°F–75°F (16°C–24°C), with 95% humidity. Ventilate when the temperature is 0–20F (0–11C) cooler than your goal: in the daytime if nights are too cold and days are mild; at night if nights are mild and days too warm. If it is very damp in there, ventilate more.

Two weeks after harvest, sort all the potatoes. By this time, any which are going to rot have likely started doing so. Restack, remembering to keep airspace between the crates and walls. For weeks 2–4, the temperature goal is 50°F (10°C) and fresh air is needed about once a week.

Potato crates in our root cellar.
Photo Nina Gentle

Long term potato storage

After week 4 in winter, cool to 40°F (5°C); in summer, below 50°F (10°C). Ventilation for air exchange is no longer needed, as the tubers have become dormant. The final long-term storage conditions are cool and fairly moist, 40°F–50°F (5°C–10°C), 85%–90% humidity—a  root cellar is ideal. Below 40°F (5°C) some starches convert to sugars, giving the potatoes a bad flavor and causing them to blacken if fried. Try hard to avoid having the cellar cool down, then warm up. That causes the potatoes to sprout.

Pre-sprouting seed potatoes

Potatoes have a dormant period of 4–8 weeks after harvest before they will sprout. The warmer the conditions after dormancy ends, the quicker they will sprout. If you want potatoes to sprout during the dormant period, trick them by refrigerating for 16 days, then pre-sprouting them in the light.

We routinely “chit” or pre-sprout our seed potatoes before planting. Bring the seed potatoes into a warm, well-lit room around 65°F–70°F (18°C–21°C) and set them upright in shallow boxes, rose end up, stem (belly-button) down, for 2–4 weeks in spring, 1–2 weeks in summer. For summer planting, store your seed potatoes in a cool place at 45°F–50°F (7°C–10°C) until 2 weeks before your planting date, then sprout them.

Seed potato pieces after pre-sprouting for planting.
Photo Kati Falger

The effects of ethylene

Ethylene is a naturally occurring, odorless, colorless gas produced by many fruits and vegetables, but it can also be produced by faulty heating units and combustion engines. Propane heaters should not be used, as propane combustion produces ethylene. Incomplete combustion of organic fuels can result in the production of carbon monoxide, ethylene and other byproducts. Do not use any unvented hydrocarbon fuel heaters near stored produce.

Ethylene is associated with ripening, sprouting and rotting. Some crops produce ethylene in storage—apples, cantaloupes, ripening tomatoes, already-sprouting potatoes all produce higher than average amounts. Chilling, wounding and pathogen attack can all induce ethylene formation in damaged crops.

Some crops, including most cut greens, are not sensitive to ethylene and can be stored in the same space as ethylene-producing crops. Other crops are very sensitive and will deteriorate in a high-ethylene environment. Potatoes will sprout, ripe fruits will go over the top, carrots lose their sweetness and become bitter.

Summary: Potatoes are more likely to sprout if they are more than 4–8 weeks after harvest; in the light; near fruits, vegetables, flowers or malfunctioning propane or natural gas heaters that produce ethylene; too warm, or warm after being cool.  Potato sprouts are toxic, see my earlier article.

Planting potatoes.
Photo Wren Vile

What Makes Sweet Potatoes Sprout?

Sweet potatoes crated in the field.
Photo Nina Gentle

The difference between Peruvian (“white”) potatoes and sweet potatoes

Peruvian potatoes (sometimes mistakenly called Irish potatoes) are stem tubers in the nightshade family; sweet potatoes are root tubers in the Morning Glory family. Stem tubers have buds, nodes and internodes, and scaly leaves, and the ability to develop chlorophyll when exposed to light. Root tubers do not have these attributes. This article is only about sweet potatoes.

The difference between curing and storage

Some vegetables need to cure before storage and the curing conditions are different from those needed for storage. Curing allows skins to harden and some of the starches to convert to sugars. These changes help the tubers to store for months.

Curing sweet potatoes

Within an hour or two after harvest, field drying, sorting and crating, take the boxes of sweet potatoes to a warm, damp indoor space to cure. Curing allows the skin to thicken, cuts to heal, and some of the starches to convert to sugars. Uncured sweet potatoes are not very sweet, will not bake well, and are best used in dishes with other foods.

In addition to promoting the healing of wounds acquired during harvesting and handling, the curing conditions are necessary for development of a protective cork layer over the whole root. And a waxy material (suberin) is produced by the root’s outer cells and covers the skin. This layer acts as a barrier to disease organisms, and prevents excess moisture loss.

Boxes of sweet potatoes curing.
Photo Nina Gentle

Curing involves optimizing three conditions: temperature, relative humidity and ventilation. Ideal curing conditions are 85°F–90°F (29°C–32°C), and 80–95% humidity for 4–7 days. Curing takes longer (as much as 3 weeks) if conditions are less than perfect. Dry air does not lead to good curing. If the air is below 66% humidity, timely good healing will not take place, and the sweet potatoes will not store well unless more time is allowed. The loss from decay in sweet potatoes cured at 50% is twice that of those cured at 82%. (Storage of sweetpotatoes, Jacob Martin Lutz, USDA, 1958)

In the past we used our greenhouse to cure sweet potatoes, but it really is too hot and sunny, and dry. Nowadays we use a heated basement. We stack our 4” (10cm) deep boxes of roots on pallets, with wood spacer bars between boxes in each stack, to ensure air flow. We use box fans to improve the airflow, and the basement already has some natural ventilation. We reckon on 10–14 days.

We get quite good temperatures, but keeping humidity up is difficult for us. We cover the flats with newspaper to hold in some moisture. Some people use perforated plastic. We have also used domestic humidifiers and we’ve tried hanging strips of wet cloth from the ceiling. The best result seems to come from splashing water on the concrete floor several times each day.

To test if curing is complete, rub two sweet potatoes together. If the skins scratch, they need to cure longer. Curing longer than needed leads to sprouting.

Sweet potato storage

Sweet potatoes can be stored in the same room they are cured in, but it is important to cool the room evenly and fairly rapidly from the curing temperature of 85°F–90°F (29°C–32°C),  to the storage temp of 55–60°F (13°C–16°C) in 10 days or fewer.

Above 60°F (16°C), shrinking, pithiness, and internal cork (a symptom of a viral disease) when the virus is present may occur, and below 55°F (13°C), a permanent chilling injury (Hard Core) can happen. The potatoes remain hard no matter how long you cook them, and are useless. Do not ever let the temperature drop below 50°F (10°C). Ideal storage conditions for sweet potatoes include 60–70% humidity, up to 85 %, with one air change each day. If the heat circulation is uneven, hot spots can develop in front of the heaters and cause severe losses. Never let hot air blow directly on the sweet potatoes. Do not store in airtight containers, sweet potatoes need one complete air change per day.

Ken Allan, in Sweet Potatoes for the Home Garden, informs us that at about 60°F (16°C), the metabolism of the sweet potato slows to near zero, meaning it won’t grow. Temperatures above 70°F (21°C) are conditions that allow growth: although slow at 70°F (21°C), the rate increases to fast at 100°F (38°C).

We use a rodent-proof “cage” in our basement. We stack the boxes directly on top of each other and this seems to keep enough moisture in. This way, assuming we had a good enough harvest, we can still have sweet potatoes into May and early June. Shrinkage occurs at 1–2 % per month if cured, 2–5 % if uncured. In some cultivars, pithiness also increases with length of storage.

Sweet potatoes do not need to be in the dark. Dormancy is generally broken by moisture and warmth, not daylight. Green sweet potato sprouts are edible, not toxic, as white potato sprouts are.

The effects of ethylene

Ethylene is a naturally occurring, odorless, colorless gas produced by many fruits and vegetables, but it can also be produced by faulty heating units and combustion engines. Propane heaters should not be used, as propane combustion produces ethylene. Incomplete combustion of organic fuels can result in the production of carbon monoxide, ethylene and other byproducts. Do not use any unvented hydrocarbon fuel heaters near stored produce.

Ethylene is associated with ripening, sprouting and rotting. Some crops produce ethylene in storage—apples, cantaloupes, ripening tomatoes all produce higher than average amounts. Chilling, wounding and pathogen attack can all induce ethylene formation in damaged crops.

Some crops, including most cut greens, are not sensitive to ethylene and can be stored in the same space as ethylene-producing crops. Other crops are very sensitive and will deteriorate in a high-ethylene environment. Potatoes will sprout, ripe fruits will go over the top, carrots lose their sweetness and become bitter. Sweet potatoes are sensitive to ethylene and should not be stored with any crops or any heating systems that produce ethylene. Symptoms are difficult to diagnose, but ethylene can cause internal darkening and pithy areas, as well as sprouting.

Accidental sprouting of sweet potatoes

If your curing or storage conditions were not right, you may get early sprouting. If this happens, snap off the sprouts and use the sweet potatoes as soon as possible. If the sweet potato also has soft and wrinkly flesh, it’s an indication that it has lost nutrients. Left longer, spouted sweet potatoes become mushy and turn brown or black.

Seed sweet potatoes growing slips.
Photo Kathryn Simmons

Intentional sprouting of sweet potatoes

Sweet potatoes that are intended for sprouting are kept under normal storage conditions, then conditioned for 2 weeks (or even 4), before you start to grow slips. Start 10–12 weeks before your planting date, conditioning at 75°F–85°F (24°C–29°C), 95% humidity for 2–4 weeks, then set to sprout. Set up a place with light, humidity and ventilation at 75°F–85°F (24°C–29°C) and 12″ (30 cm) of headroom.

Summary: Sweet potatoes are more likely to sprout if they were cured for too long; curing conditions were too far from ideal; temperatures stayed too high—above 60°F (16°C)—once the sweet potatoes were cured (especially at high humidity); they were exposed to low temperatures followed by higher ones; they were physically damaged or stored near ethylene sources.

Sweet potato harvest
Photo Nina Gentle

Soil tests and high phosphorus levels

I just got back from the Carolina Farm Stewardship Association Conference, where I had a great time. I will be posting my slideshow Sequential Planting of Cool Season Crops in a High Tunnel here next week, after I’ve added back in some of the material I had to cut to fit the time slot. Meanwhile here’s some in depth thoughts about phosphorus levels, an issue for those of us who pile lots of animal manure or compost on our gardens.

Soil pH analysis machine at Virginia Tech.
Photo from Virginia Tech

This is the best time to get a Soil Test

            Get an annual soil test in the fall, from the same agency each time—different labs sometimes use varying test methods. Also, soil collected in spring is usually higher in P than soil collected in the fall. Consult an agronomy book, your extension service, or a live agronomist for help in interpreting your test results. Most soil tests don’t include a measure of organic matter as this can vary a lot from week to week. My state extension service provides standard tests for soil pH, P, K, Ca, Mg, Zn, Mn, Cu, Fe, B, and estimated CEC, plus a fertilizer and lime recommendation. For a small fee there are special tests for soluble salts and organic matter.

Amendments and the Issue of High Phosphorus

High levels of soluble salts, including nitrate, potassium, and sulfate from fertilizers or organic materials like compost can build up and stunt plant growth.  Some of the salt problems are caused by having very high organic matter levels, due to heavy amendment with composts or manures. In high OM soils, when warm or when irrigated after a dry spell, large flushes of nitrate can occur. This makes it difficult to manage nitrogen levels.

Organic soil amendments include soil inoculants, organic mulches, biochar and other soil conditioners, lime and other natural minerals, manure and other organic fertilizers, such as alfalfa meal, soybean meal, fish meal, kelp, composted chicken litter and compost.

Screening compost from a huge pile, for spring seedling compost.
Photo Wren Vile

Most growers are lavish with compost when they can be. Good quality finished compost is a way to add organic matter and nutrients. Compost can add a range of beneficial bacteria and fungi, which can inoculate plants against diseases by inducing systemic acquired resistance. The plants produce antibodies and other protective compounds before any infection can occur. Compost improves the soil structure, organic matter and humus. The effects last longer than cover crops and crop residues, especially in humid conditions where the breakdown of plant material is very rapid.

How much compost is too much? Some of us were raised to think of compost as the gold standard soil improver, and find it hard to believe there can be too much of a good thing. Others may consider compost like salad dressing—something to add that je-ne-sais-quoi to a good meal.

Compared with poultry litter compost (lower C:N  ratio), on-farm mixed compost (high C:N) leads to higher total soil organic C and N, higher N mineralization potential and better water infiltration. Poultry litter compost can enhance organic matter and N mineralization potential over conventional systems, but can lead to excess P. In terms of organic matter, composted manure is better than uncomposted solid manure, and both add more than slurry manure (which provides very low C:N; and half of the N is ammonium).

Manure and compost can add too much P relative to N and K. It is worthwhile to understand the effect of phosphorus.

Phosphorus in the Soil and in Plants

Phosphorus is needed for cell division, hence to promote root formation and growth, vigorous seedlings, flowering, crop maturity and seed production, and to improve winter hardiness in fall plantings. Phosphorus is important in fat, carbon, hydrogen and oxygen metabolism, in respiration, and in photosynthesis. It is stored in seeds and fruit.

Phosphorus binds easily with many other minerals in the soil, forming compounds that are not very soluble in water, therefore most of the phosphate in soils exists in solid form and phosphorus does not move freely with soil water. Although P is very mobile within plants, it is relatively immobile in soil and does not leach readily in normal rainfall or irrigation.

P is most available to plants between soil pH of 6 and 7.5, especially pH 6.5-6.8.

In neutral and alkaline soils P is mostly present as insoluble calcium phosphates. In acid soils below pH 5.5, most of the P is bound as iron phosphate or aluminum phosphate, compounds that further change gradually into very insoluble compounds not available to plants. If a soil test shows a pH that is far from neutral, with a slightly low P level, correct the pH and repeat the soil test before amending the P level.

In the soil water, P is only present in very small amounts, but when removed by plants, supplies are quickly replenished from the “active P pool” (P in solid compounds which is relatively easily released to the soil solution). The “fixed P pool” contains inorganic phosphate compounds that are very insoluble, and organic compounds that are resistant to mineralization by microorganisms in the soil. Although some slow conversion between the fixed P pool and the active P pool does occur in the soil, phosphate may remain for years without being available to plants and may have very little impact on soil fertility.

Since the movement of phosphates in soils is very limited, roots have to grow to the phosphorus—it will not move towards the plants. Manure contains soluble phosphate, organic phosphate, and inorganic phosphate compounds that are quite available. Water-soluble forms generally become insoluble very soon after application to the soil.

Phosphorus Deficiency

In cold soils less P is available from organic materials, because biological activity is required to release it and it runs slow when it’s cold. Also, roots cannot absorb P well from cool soils.  Early spring brassicas can show red or purplish colors (anthocyanin pigment) in the leaves, especially undersides, and the lower stems. Cell necrosis may follow. Root growth will be poor, plants may exhibit stunting and delayed maturity. Tomato plants may have yellow leaves, with purpling on the underside of leaves. They may exhibit reduced flowering and delayed maturity. To avoid P deficiency problems, wait until the soil is 60°F (15.5°C) before planting.

Effects of excess soil salt levels on crop foliage.
Photo Rose Ogutu, Horticulture Specialist, Delaware State University

Excess Phosphorus

The main symptom of excessive phosphorus in soil is stunted plant growth. High P interferes with N absorption. Also there may be symptoms of deficiencies of zinc, iron, cobalt or calcium, because the P has locked up these nutrients.  Zn deficiency shows as bleaching of plant tissue, Fe deficiency as yellowing between leaf veins. Co is involved in the process by which the plant stem grows, shoot tips elongate, and leaves expand. Ca deficiency produces blossom end rot of tomatoes.

Phosphorus inhibits the growth of mycorrhizae which help the plant absorb water and nutrients. Increased growth of non-mycorrhizal weeds such as velvetleaf, lambsquarters, pigweed and galinsoga can be sign of excess P, explained Klaas Martens at MOFGA’s 2009 Spring Growth Conference.

Aside from plant growth problems, the issues with having very high P levels in your soil include that if it reaches waterways it can accelerate eutrophication—the nutrient enrichment of surface water leading to problem algal growth. When an algal bloom dies, it decomposes, using up the oxygen in the water, so fish and other organisms die too. Phosphorus is a paradoxical element in that it is an essential nutrient, is not toxic itself and has low solubility, but can have damaging effects on water quality at quite low concentrations.  Because P is usually locked up, leaching of soluble P from soils is not normally a problem, but if soil particles are carried to a river or lake, P is contained in this sediment.

Mitigating High Phosphorus Levels

Ear of triticale.
Photo triticale-infos.eu

The quickest way to reduce excess soil P (which can take years!) is to stop any manure or compost application while continuing to grow crops that can be eaten or sold. One solution for vegetable growers may be to grow cover crops as forage crops, and graze or bale grass crops to sell off the farm as livestock feed. For example, triticale is very good at removing P from the soil and producing winter forage. The P removed ranges from 7–36 pounds/acre (7.8–40 kg/ha). The more P your soil has, then the higher the P level in triticale grown in that soil. Double cropping can remove P at twice the rate.

Vegetable growers do not have the problem of P accumulation to such a big degree as livestock farmers, nor do vegetable crops remove P at the rate forages do. See the New England Vegetable Management Guide Removal of Nutrients from the Soil for a table of Approximate Nutrient Removal by Selected Vegetable Crops. The best vegetable removers of P are celery (80 lbs P2O5/acre, 90 kg/ha), tomatoes (72 lbs, 81 kg), potatoes (65 lbs, 73 kg), sweet potatoes (60 lbs, 67 kg), peppers (52 lbs, 58 kg, fruits only), cucumbers (33–72 lbs, 37–81 kg), eggplant (56 lbs, 63 kg). Onions remove about 25 lbs (28 kg/ha) one-quarter of the P removed by alfalfa hay (104 lbs, 117 kg) In all cases, to achieve results this high, grow high yields and remove the vines too, although you can’t sell those! Beans and peas are in the 7–10 lbs (8–11 kg) range if just pods, 20 lbs (22 kg) with vines. P2O5 is 43.7% P.

Celery, the star of phosphorus-removing vegetable crops.
Photo Kathryn Simmons

Strategies to reduce the amount of P added each year include adjusting your compost use rates according to soil test P results. On low-P soil, use at rates to meet the soil needs for N or K, which will  increase P levels. If the soil P is high or optimum, use compost sufficient to just replenish P, and legume cover crops (or legume food crops) to supplement N. For very high or excess soil P, only use compost sparingly as a micro-organism inoculant, rather than a fertilizer, and  if  test reports show more than 40 lbs P per acre (45 kg/ha), consider using only soil amendments containing little or no P. If phosphorus levels are excessive, avoid using manure composts (high in phosphorus), and other fertilizers and amendments containing phosphorus. Add more carbon (“brown”) ingredients to compost you make on-farm.

 

Sowing hoophouse winter crops

New spinach seedlings in our hoophouse.
Photo Pam Dawling

We are on our way with our late fall, winter and early spring crops in the hoophouse. On September 6 and 7 we sowed five crops in our first bed – spinach, tatsoi, Bulls Blood beet greens, radishes and scallions. On September 15 we sowed lettuces, chard, pak choy, Chinese cabbage, Tokyo Bekana and Yukina Savoy, in an outdoor bed to be transplanted into the hoophouse in a few weeks, after we’ve prepared another bed.

Broadfork from Way Cool Tools.
Photo Way Cool Tools

To prepare hoophouse beds for winter crops, we first remove the summer crops to the compost pile, then spread a generous layer of compost over the surface. We use about five wheelbarrowsful for one bed 4’ x 90’. Next we move the three lengths of drip tape off to one side or the other, and broadfork the whole area. We have an all-steel broadfork from Way Cool Tools that we really like. To use a broadfork, work backwards either going the length of the bed or the width. Stab the tines into the soil and step on the crossbar, holding the long handles. Step from foot to foot until the bar touches the soil, with the tines all the way in, then step off backwards, pulling the handles towards you. This loosens a big area of soil, which hopefully crumbles into chunks. Lift the broadfork and set it back in the soil about 6” back from the first bite. Step on the bar and repeat. We’ve found it’s important to only broadfork the amount of space you have time to rake immediately, otherwise the warm hoophouse conditions dry out the soil and make it harder to cultivate into a fine tilth, which is the next task. Sometimes we use a rake, breaking the clumps up with the back of the rake, then raking the soil to break up the smaller lumps, and reshape the bed.

7″ stirrup hoe.
Photo Johnnys Selected Seeds

Sometimes we use a wide stirrup hoe very energetically. This isn’t the job scuffle hoes were designed for (that’s very shallow hoeing, and hence why we call them scuffle hoes), but the sharp hoe blade does a good job of breaking up clumpy soil. We’ve also found it important to lay the drip tapes back in place in between each day’s work, so that the soil gets irrigated when we run the system and stays damp. We don’t want dead, baked soil.

Once the bed is prepared, we measure out the areas for different crops and mark them with flags. Next we use our row-marker rake (bed prep rake) from Johnny’s Selected Seeds.

Johnny’s Bed Prep rake with row marker pegs.
Photo Johnnys Selected Seeds

We plant crops closer in the hoophouse than outdoors, and closer to the edges of the beds. We don’t have many weeds in the hoophouse, and the paths are marked off with twine, to keep us from stepping on the beds, compacting the soil. We find that the soil does slump and compact some of its own accord, even if we don’t step on the edges (and of course, some feet do find themselves on the bed edges sometimes), hence the once-a-year broadforking. We found out how valuable the soil loosening is, because one year before we started broadforking, we decided to loosen the edges with a digging fork to make up for several years of accidental steps. The edge rows of spinach grew much bigger than the inner rows, and we realized that the whole bed needed loosening.

After the rowmarking, we deepen the furrows if needed (often it’s not needed), using a pointed hoe, then sow the seeds. We pre-sprout our spinach for a week in a jar in the fridge. Just soak the seed overnight, drain it in the morning, fit a mesh lid on the jar, and lay it on its side in the fridge. Once a day, give the jar a quarter turn to tumble the seeds and even out the moisture. This year the seeds were a bit wet when I came to sow them, and clumped together. I poured them out on a cloth to dry a bit before I sowed. This year we are growing two varieties (Avon and Reflect) side by side, still seeking a replacement for our much loved Tyee, which was pulled from the market, because it was prone to a disease prevalent in the West.

Easter Egg radish seedlings in our hoophouse.
Photo Pam Dawling

The spinach, tatsoi and radishes came up very quickly, with the beets a day or two behind. The scallions came up in a week, which is quicker than at other times of year.

One week after the sowings, I thinned the spinach and radishes to 1” apart in the row. We are growing Easter Egg, Cherry Belle and White Icicle radishes. The Cherry Belle will be ready first, Easter Egg next (they mature relatively gradually, giving us a nice harvest period). Icicle are unusual long white radishes which are slower to mature, and slow to get woody.

Buckley One-cut (Eazileaf) lettuce.
Photo High Mowing Seeds

Meanwhile, outdoors on September 15 we sowed the first half of the crops that we transplant bare-rooted into the hoophouse. Our planned schedule called for 10 varieties of lettuce, but I ended up sowing 12, partly because we are trying three new Vitalis one-cut lettuce varieties from High Mowing Seeds: Ezrilla, Hampton and Buckley.  These are bred to provide lots of similar-sized leaves from cutting. They can be cut and mixed for baby salad mix or cut as whole heads for easy-to-prepare salads, or harvested by the leaf (or layers of leaves) once the plant has grown to full size. This is how we use them. They were previously called Eazileaf varieties, and are now called One-cut lettuces. They are only available as pelleted seed, so I regard them as too pricey to grow for baby salad mix, and best used for multiple harvests.

Johnny’s Green Sweet Crisp Salanova lettuce.
Photo Johnnys Seeds

Osborne’s Multigreen 3 lettuce.
Photo Osborne Seeds

You can click here to read the New Head Lettuces article Andrew Mefferd wrote about this new type of lettuce in Growing for Market magazine. We have previously grown Johnny’s Salanova and Osborne’s Multileaf varieties and I wrote about them here and here. This year we are trying the High Mowing ones. We did a small trial of them outdoors in spring, knowing that in our climate (very different from High Mowing’s in Vermont) they might well bolt. They grew into handsome plants, but clearly they are more suited to fall than spring in our quickly-heating-up climate.

Other lettuces we sow for our winter hoophouse crops include Oscarde, Panisse, Tango which have a similar shape of lots of same-sized leaves, and Green Forest (romaine), Hyper Red Rumpled Wave, Merlot, Revolution, Salad Bowl and Red Salad Bowl. I would have sown Red Tinged Winter but we seem to be out of seed.

Red Salad Bowl lettuce.
Photo Bridget Aleshire

Hoophouse tomato varieties

Tall tomatoes with beans and cucumbers in our hoophouse.
Photo Wren Vile

Our hoophouse tomatoes are doing well this year. Apart from the determinate Glacier, they’ve reached the top of the stakes and as high as we can string-weave or pick. We transplanted them March 15, a month before our last frost date. We harvest each of our hoophouse beds every two days,alternating them to smooth supplies.We plan to harvest for ten weeks from May 25 till July 31, by which time our first outdoor planting is yielding well. In the South many of us grow only our early tomatoes in hoophouses, as outdoor crops produce abundantly once the weather warms. We harvest our outdoor tomatoes (sown 3/15) from July until frost, initially overlapping with our hoophouse earlies, then on their own.

Ken Dawson in Cedar Grove, NC, has a succession planting plan for outdoor tomatoes. He makes four field plantings at three week intervals. In cooler climates, because yields will be higher, it is more common to grow tomatoes in hoophouses whenever possible, and keep them growing for the whole season.

Glacier tomatoes in our hoophouse in late June.
Photo Pam Dawling

It is possible to grow successions of determinate tomatoes in a hoophouse, but any advantages are usually outweighed by the disadvantages of disease spread and the extra time plants spend before they reach production. In the past we grew a late hoophouse crop, to take us beyond the first frosts. We sowed June 18 and transplanted at a relatively young age (tomatoes grow quickly by that point of the year). We gave this up in favor of growing more leafy greens.

Each year I take notes on the varieties we have in the hoophouse, and often we run a taste test. I have also been gathering information from other growers, on which varieties do well for them. Before I get into talking about specific varieties, I want to say a bit about types of tomatoes.

Determinate Varieties

Varieties can be divided into two main growth types and then the exceptions. Determinates (bush tomatoes) are compact varieties that stop growing at a height of 2′-4′ (0.6-1.2 m). The number of stems, leaves and flowers is part of the genetic makeup of that variety. The number of leaves between one fruit cluster and the next decreases by one each time a cluster is produced, until the terminal cluster forms. No more leaves or flowers develop after that. The fruit ripens and the plant starts to die back. Harvest can be 1-3 months from start to finish. Because they are faster to mature than indeterminates, they are often chosen for early crops. Determinate varieties usually bear lightly the first third of the  harvest period, heavily the second, then lightly for the last third, so it is not very productive to plant crops so late that they don’t reach their second (main) month of production before frosts. Determinates need no pruning as the yield of fruit is inherently limited. Most need little staking, but some determinates are quite tall, and produce for quite a long season.

Tomato Mountain Magic in our hoophouse.
Photo Pam Dawling

Fast-maturing Tomato Varieties

Currently Glacier (56d det red) is the only determinate we grow. We simply choose varieties for our early bed based on days to maturity, past experience and inspiring catalog write-ups! They have to be 71 days or fewer from transplant to maturity. We like Stupice (61d ind red), Mountain Magic (66d ind red), Garden Peach (71d ind yellow) and the very fast and delicious cherry Sun Gold (57d ind orange) and Five

Sun Gold cherry tomato in our hoophouse.
Photo Pam Dawling

Star Grape (62d red). We found out the hard way that growing too many cherries is not wise – they take a long time to harvest and when you compare yields it’s clear they don’t add up to much. We grow two plants each of Sun Gold and Five Star Grape, 6 each of Garden Peach and Mountain Magic, 13 Stupice and 16 Glacier. Very biased towards the earliest.

 

Indeterminate Varieties

Jubilee tomato in our hoophouse.
Photo Pam Dawling

We choose our favorite workhorses along with some unusual heirlooms for our second bed. Most heirlooms are indeterminate. We grow lots of Jubilee (80d ind orange) and Tropic (80d ind red). The just two or three each of the fun and interesting Green Zebra (76d ind green stripes on gold), Striped German (78d ind red/yellow), Amy’s Sugar Gem (75d ind red), Rebelski (75d ind red) and two each of two more cherries, Amy’s Apricot (75d ind apricot) and Black Cherry (70d ind purple-brown)

Green zebra tomato in our hoophouse. Photo Pam Dawling

Indeterminate varieties can continue to grow and produce more fruit as long as the weather is warm enough, and as long as they don’t get struck down by frost or disease. The number of leaf nodes between one cluster and the next remains the same all the way up the vine. Indeterminate tomatoes need substantial support. Pruning is not essential – whether or not to prune depends on your climate, the varieties you are growing and how long you plan to keep the plants for.

Amys Apricot cherry tomato in our hoophouse.
Photo Pam Dawling

Semi-determinate varieties

Semi-determinate tomato varieties are larger than determinate but smaller than indeterminate plants. Some seed suppliers just call them large determinates. These plants usually require staking.

Making Choices

If you are growing in a cold climate you will probably want to grow indeterminates in your hoophouse and keep them all season, as it takes a long time to grow a tomato plant. If you are growing in hot climates, you will probably only grow your earlies in your hoophouse and then grow a succession of outdoor tomato crops. If you grow where there are lots of tomato diseases, you will do better with succession planting than having all your eggs in one tomato basket. If your season is long enough for multiple plantings, you might choose to start with fast determinates to catch the early market.

Jamaica Sustainable Farm Enterprise Program

 

I’m back from Jamaica, compiling my trip report. I went as a volunteer with a farmer-to-farmer training project for 9 days (plus two travel days). I was a volunteer with the FLORIDA ASSOCIATION FOR VOLUNTEER ACTION IN THE CARIBBEAN AND THE AMERICAS (FAVACA), funded by the United States Agency for International Development (USAID) From the American People established by John F Kennedy in 1961. USAID is the lead U.S. Government agency that works to end extreme global poverty and enable resilient, democratic societies to realize their potential. One of the FAVACA programs is the Jamaica Sustainable Farm Enterprise Program.

For those who don’t know Jamaica at all, let’s start with a map of the island, which is south of Cuba.

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I was hosted by the Source Farm Ecovillage, Johns Town, St Thomas Parish, Jamaica. Here’s a more detailed map with St Thomas parish colored in pink. The Source Farm is east of Morant Bay, very near the coast.

The Source Farm Foundation and Learning Village is a multi-cultural, inter-generational eco-village, located in Johns Town, in the parish of St. Thomas, Jamaica.

“Our ecological mission and vision is to respect natural life, its systems and processes – preserving wildlife and botanical habitat, and creating a life-style that regenerates, rather than diminishes the integrity of the source farm environment.”

Here is a 2014 site map, showing roughly what buildings are there, and where the gardens are located. Actually the gardens have expanded quite a bit since this map was drawn.

I stayed in Earthbag 1, a house built of stacked bags of bauxitic soil with cement, rendered over with cement, giving an adobe effect. The structure stayed fairly cool. The windows had no glass, but insect screens and wood louvered shutters. I’ve never actually had a house to myself before, even a small one like this!

The newer houses in the eco-village are monolithic concrete domes, which hold up very well against hurricanes, earthquakes and termites. Jamaica is rich in marl (lime) and other minerals, and there is a cement works near Kingston. Because many other homes on the island are built from concrete block covered with cement rendering, there are many workers skilled in rendering, who can quickly adapt to dome houses.

I got to taste many kinds of mango, passion fruit, star fruit, star apple, ackee, bammy (cassava flatbread), yam, breadfruit, callalloo (amaranth leaves) and meringa seeds, as well as foods I was already familiar with. I had an especially lovely supper with Nicola and Julia, of snapper with bammy and festival (described by April Jackson on The Yummy Truth as a Jamaican savory beignet made with cornmeal), and Red Stripe beer at Fish Cove Restaurant by the ocean.

Festival, bammy and fish in Jamaica.
Photo https://theyummytruth.wordpress.com/tag/jamaican-fried-fish/

What is on the Farm?

Photo courtesy of
The Source Farm

My teaching work was organized by the people at Source Farm and included the whole group of farmers in JSFEP. The schedule included several farm visits, but unfortunately it rained very hard for four or five days (this was meant to be the dry season!) and many areas were flooded. One farmer told me that the biggest challenges to farming in Jamaica are climate change and theft. Both are serious. The heavy rains I experienced showed how much damage unusual weather can cause. At one farm, where a co-operative onion-growing project was underway, one farmer got trapped by rising waters and had to be helped by two other farmers to swim and wade through the wild waters. After that, the farmers in the group had to take turns to guard the place so that the drip irrigation equipment didn’t get stolen. Another farmer told me about losing an entire crop of sweet potatoes one night – someone dug up the whole lot. The thefts, of course, are related to poverty and desperation in some cases, and a culture where each person has to take what they need as there is little in the way of government support. And a history of colonialism with sugar cane and banana cash crops, followed by a crashing economy.

The roads are in poor shape and in rural areas people rely on calling taxis to get from one place to another. Everyone needs a phone to live this way, and I saw some very battered up phones and chargers carefully repaired and kept running. Arranging a meeting time requires a flexible attitude about timeliness.

The farmers were looking at increasing production, planning planting quantities, scheduling succession plantings, and considering new crops. I met one-on-one with a few farmers, and I did some research into the possibilities of growing asparagus and garlic in the tropics, for a couple of them. I had to get my head round the idea of planting a sequence of three crops each needing four months. No winter cover crop cycle. Cover crops are very different from ours. Some overlap – sorghum-sudangrass, sunn-hemp. But no place for winter cereals! The principle of feeding the soil stays the same, using legumes to add nitrogen, bulky cover crops to smother weeds and add biomass.

I was teaching vegetable crop planning, crop rotations, and scheduling co-operative harvests to help the farmers double their presence at the Ujima Natural Farmers Market  to every Saturday rather than very other Saturday, starting in June. The demand for sustainably grown fresh local produce exists, and farmers are interested in learning to boost production.

On the second Saturday I was there, I gave a workshop on crop planning, to 22 farmers, and we got some lively discussion going, as they offered each other tips, and diagnosed some diseased carrots (looked like nematodes to me).

I treasure the time I spent in Jamaica, even though it wasn’t all sunshine and mangoes. I met many wonderful farmers and enjoyed my stay in the Source ecovillage, which reminded me somewhat of Twin Oaks Community, where I live in Virginia.

 

 

 

 

Book Review, The Greenhouse and Hoophouse Grower’s Handbook, by Andrew Mefferd

The Greenhouse and Hoophouse Grower’s Handbook,  Organic Vegetable Production Using Protected Culture. by Andrew Mefferd. Chelsea Green.March 2017, $34.95. ISBN 978-1-60358-637-5

I was lucky enough to be asked to write an endorsement for this book, and was sent an uncorrected proof to read. Now I have the full color, published version, and I’m poring through it once again. Andrew Mefferd is the editor and publisher of Growing for Market magazine that I sometimes write for. Prior to that job, he worked at Johnny’s Selected Seeds, in the research department for seven years. Born in Virginia, he apprenticed on farms in six states on the west and east coasts, then farmed in Pennsylvania. He now farms in Maine, and has a good appreciation for the difference a different climate can make.

This is not an “Everything you always wanted to know to get started with a hoophouse” book, nor a compendium of greenhouse crops, pests and diseases. On the contrary, this book focusses down on the precise details of successful practices to grow what Andrew has determined to be the eight most profitable crops using protected culture: tomatoes, peppers, cucumbers, eggplant, lettuce, greens, microgreens and herbs.

This is a book to come back to each time we want to know more about one of his topics. If I were about to launch into microgreens, I would follow Andrew’s methods. I tend to read quite widely on vegetable growing topics and I’ve read some very fussy time-consuming microgreens-growing instructions for home gardeners. I haven’t seen another book be so down-to-earth with an efficient and professional growing method that uses only simple tools and supplies. Those wanting to grow microgreens in quantity, and make a living from it will find plenty of information to get started or to fine-tune their operation.

The part of the book I’m most excited about right now is the information on what plants need at different stages of growth, in terms of balance between temperature, humidity as it affects transpiration, daylength, light intensity, carbon dioxide, oxygen, water and nutrients; and how to use this information for “crop steering” – adjusting conditions to select for leaf growth or fruit development. Here are the details to get it right. I once got a light meter to compare the light transmission through clouded old glass and new glass (I wanted to know if it was worthwhile to replace the glass in our greenhouse). But then I didn’t know how to use the information. Now I know that 1% less light will lead to about a 1% lower yield. Specific information like this can be hard to dig up bit by bit on the web. Here the gold nuggets have been screened for us, and the mud left behind.

The book starts off with a sixty page section on the basics of protected culture: the why, what and how of the various options of structures and utilities you might be choosing among, with a chapter on economics and efficiencies. The main part of the book then dives into the specific practices that help the eight crops do best. Chapters on propagation, pruning and trellising; temperature control and crop steering; and grafting are applicable to many of the recommended crops. Next follow chapters on each of the crop groups, and appendices on hydroponics, pests and disease and tools and supplies.

Andrew is obviously a very attentive farmer, and one who keeps good records. And here we can all benefit, whether experienced growers looking to improve our game, or beginners wanting to grasp success from day one. Serious backyard gardeners could use this book too, not only commercial growers. Facts are facts, results are results. Not everyone will want to follow all of the recommendations immediately or perhaps ever. In our hoophouse in Virginia, we grow two beds of early tomatoes in our hoophouse with just enough trellising to keep them upright, and minimal pruning. As soon as our outdoor tomatoes are producing well, we pull out the hooophouse rows. Our climate doesn’t warrant keeping them in the hoophouse, and in fact, it may get too hot in there for them. Our climate is full of fungal diseases, so crop rotation is very important to us, and the sooner we don’t need tomatoes in the hoophouse, the sooner we can remove them and their fungal spores!

But I do remember growing tomatoes in a glass greenhouse in northern England, and how we cherished those plants! I had started to experiment with side-grafting 25 years ago, in hopes of having sturdier tomatoes. We pruned and twined, and every ripe tomato was precious to us. It was late September when I moved to Virginia, and I helped the garden crew harvest Roma paste tomatoes, which were grown sprawled on the ground. That in itself was a shock – gosh these people don’t hold their tomatoes in very high regard, they let them rot on the ground! The crew member working next to me shocked me further: “Stomp on the green ones” she muttered under her breath. Apparently so great had been the harvest of these paste tomatoes that the crew was exhausted from harvesting and wanted to be done!

So, select the sections of Andrew’s book that speak to your needs and your climate. There’s something for everyone. You don’t need to abide by it all to want the book. It will easily pay for itself if you find only one new practice to adopt this season. But read the whole book anyway, and you can develop a fuller understanding of the big picture, a new management strategy and a set of skills to deal with the challenges that arrive unbidden. Andrew has tested all these practices as a small-scale grower himself, and he does this because he’s a passionate supporter of local food, sustainably grown, and sees protected cropping as a way to increase local food production by increasing on-the-ground crop insurance in the face of the unpredictable.

Young tomato plant in our hoophouse in April.
Photo Kathryn Simmons

Growing for Market, Sweet potato propagation and yields

The April issue of Growing for Market is out! For those of you growing sweet potatoes, Andrew Schwerin from NW Arkansas has written an interesting article. I’ve written about starting sweet potato slips before and I have a slideshow that includes three methods of  starting your own slips.  He and his wife Madeleine grow 1500 feet of sweet potatoes each year, a third of their growing area.

I was interested to note their reasons for growing so many sweet potatoes (apart from the obvious fact that they can sell that many). Sweet potatoes are not a big moneymaker in terms of the space occupied. Here at Twin Oaks we pondered similar issues this winter when deciding which crops to grow.  We worked down a list of 25 factors, deciding which were important to use. We chose our top handful of factors and then worked down a list of crops we might grow, awarding points (or not!) for each factor for each crop. This helped us narrow down what to focus on this year. And yes, we are growing sweet potatoes! I wrote about this in Growing for Market in February 2017.

These growers listed the following factors as their reasons to grow sweet potatoes:

  • Sweet potatoes produce well in our soil

  • They aren’t troubled by intense summer heat

  • Extensive vines will smother most weeds

  • Few pest or disease issues

  • Most of the labor is in early October, between intensive harvests of summer and fall crops

  • They store long-term for steady sales through the winter

Sweet Potato harvest at Twin Oaks. Photo McCune Porter

They like Beauregard, and wanted to try using the single node cutting method, as advocated by Anthony and Caroline Boutard – see my Sweet Potato slideshow for details. Initially they were excited about the single node cutting process, as their roots produced exponentially more growing shoots each week. OK, maybe exponential is a bit of an exaggeration, but it gives the sense of it. Because they had so much propagation material, they started making 5-node slips, rooting clusters of cuttings in pots of compost, 3 nodes in the soil for roots, 2 nodes above ground.

Some of their single node cuttings failed to thrive, both in the trays and in the field, so they developed a 2-node cutting system instead, and also used their five-node slips. And so they had a trial of three sweet potato cutting methods, with plants in different 100 ft beds. In the past (using the regular slips method) they have averaged yields of 500-600 lbs of sweet potatoes per 100 ft bed, with a range from a poor 250 lbs to a few successes with 1000 lbs/bed. Of course, yield is not the only important feature of a market crop, although understandably it has a high profile for those growing 1500 row feet for sale.

At harvest, they found that their single-node sweet potato plants were producing a couple of hundred pounds per 100 ft bed. The 2-node beds produced about 500 pounds per bed, of relatively few, very large (6 – 20 lb) sweet potatoes. The plants with 3+ nodes in the soil gave more reasonable sized potatoes. They tend to get jumbos, so they have started planting closer (10″) to tackle this – not many customers want jumbos.

In his article in Growing for Market,  Anthony Boutard pointed out that single-node cuttings do produce fewer tubers which are larger and better formed. This is a big advantage for growers in the north, but less so in the south. The Arkansas growers have found that the 2-node cuttings are even better at this tendency in their location, which is much further south than Anthony Boutard’s farm.

Beauregard sweet potatoes saved for seed stock.
Photo Nina Gentle

Other articles in this month’s Growing for Market include Managing a cash crisis
How to climb out of the hole by Julia Shanks, the author of The Farmer’s
Office. Farmers deal with a very seasonal cash flow, and may well have gone into farming with good farming skills but not good business skills. Julia writes about four rules for getting out of a financial hole.

  1. Quit digging (don’t incur any more inessential expenses).
  2. Keep the dogs at bay (communicate with your creditors about how you plan to pay, and how you plan to keep producing the goods).
  3. Climb out (increase revenue in as many ways as possible).
  4. Get your head out of the sand (don’t panic, face realities, be proactive).

She goes on to list 10 ways to protect yourself from getting in such a hole again.

Sam Hitchcock Tilton has an article about cultivating with walk-behind tractors, ie, weeding and hoeing with special attachments. There are some amazing walk-behind
weeding machines (manufactured and homemade) throughout the world. There
is an entire style of vegetable farming and scale of tools that have been forgotten, in between tractor work and hand growing – the scale of the walk-behind tractor. The author explains how commercially available tools can be adapted to work with a BCS or a carefully used antique walk-behind tractor.

Mike Appel and Emily Oakley contributed Every farm is unique, define success your own way. Money is not the only measure. Quality of life, family time, and personal well-being are up there too, as are wider community achievements. Farming is equal parts job and lifestyle, and the authors recommend having a strategic plan for yourself and the farm, which you update every couple of years to pinpoint goals and the steps you need to take to reach them.

Cossack Pineapple Ground Cherry
Photo Southern Exposure Seed Exchange

Liz Martin writes about husk cherries (ground cherries) and how to improve production of them, to make a commercial crop viable. Who would have guessed that hillling the beds before planting can make harvest so much easier, because the fruits roll down the sides?

Judson Reid and Cordelia Machanoff wrotea short piece: Fertility tips and foliar testing to maximize high tunnel crops, and Gretel Adams wrote about  Scaling up the flower farm. Many of the ideas also apply to vegetable farms.

Hoophouse seasonal transition to tomatoes, peppers, squash, cucumbers

This past weekend I was at the Organic Growers School spring conference in Asheville, NC. I presented my workshop on Spring and Summer Hoophouses twice. This link will take you to a blog post where you can get the handout. An older version of the slideshow is at this SlideShare link. Later this week I will tweak the presentation a little and upload the revised version. It wasn’t very spring-like in Asheville. We got 3″ snow, but gardeners and farmers are a hardy lot, and attendance was still good. My workshops were packed (the room was quite small).


Young tomato plant in our hoophouse.
Photo Kathryn Simmons

Now I’m home and we had snow in the forecast for Monday night, but got ice pellets instead. The worst of the weather passed us by. It’s still very cold though, and so we are delaying transplanting our early tomatoes in our hoophouse, which we had scheduled for 3/15 and 3/16. The photo above shows where we’re headed: sturdy transplants in the middle of the bed, with wire hoops to hold rowcover on cold nights. Here’s where we are now:

March hoophouse bed prepared for tomato planting.
Photo Wren Vile

When we make the transition from hoophouse winter crops to early spring crops, we don’t clear the whole bed. First we harvest out the greens down the middle of the bed, then measure and dig holes every two feet and put a shovelful of compost in each hole. Within a couple of weeks after transplanting the tomatoes, we harvest the greens on the south side of the bed, as they will block light from the new crop. After that we harvest the greens on the north side. This allows us to keep the greens later, which covers the time (the Hungry Gap) until the new spring plantings of outdoor greens start to produce.

Tomato transplants in March, ready to plant in our hoophouse in milder weather.
Photo Wren Vile

Meanwhile the tomato transplants are in pots in our greenhouse, where we can keep them warmer at night with rowcover. Our greenhouse stays warmer at night than our double-poly hoophouse. It has a solid north wall and double-pane glass windows (old patio doors).

We use the same method for our peppers, cucumbers and yellow squash, transplanted 4/1. In the photo below you can see the winter crop of Bulls Blood beets, which we grow for leaves for salad mixes, discarded beet stems, young squash plants and one of the wire hoops that hold rowcover on freezing nights.

Young summer squash plants in the hoophouse, surrounded by Bulls Blood beets.
Photo Kathryn Simmons

In the hoophouse we have three crop seasons:

  1. winter crops planted in the fall, harvested November to April (some spinach to May)
  2. early warm weather crops planted in March and April, harvested June and July (peppers to November)
  3. high summer crops planted in July and harvested August to October.

 

Lettuce in February, Growing for Market, open seed flats

Baby lettuce mix in our winter hoophouse.
Photo Twin Oaks Community

We still have plenty of lettuce to eat, although our first sowing of baby lettuce mix in the hoophouse has come to its bitter end, and the second sowing isn’t quite ready (I think we sowed it a bit later than intended). We are still harvesting leaves from the large lettuce we transplanted in October.  Soon we’ll have the second and third baby lettuce mix sowings to bring a welcome change. We are about ready to transplant our first outdoor lettuce, to feed us mid-late April.

Here is a month-by-month planting and harvesting narrative for our hoophouse lettuce in Zone 7, from September to April:

September: Sow cold-hardy varieties in the second and third weeks (outdoors or in your greenhouse) to transplant into the hoophouse at 4 weeks old .

October: 4 weeks after sowing, transplant those lettuces at 8” spacing to harvest leaves from mid-November to early March, rather than heads. In late October, sow the first baby lettuce mix, for up to 8 cuts from early December to late February, and sow a small patch of “filler lettuces” to replace casualties in the main plantings up until the end of December.

November: 11/9 sow more filler lettuce, to be planted out in the hoophouse during January. Transplant the first “filler lettuce” to replace casualties. Harvest leaves from the transplanted lettuce.

December: Use the “filler lettuce #1” to replace casualties or fill other hoophouse space, for lettuce leaves in January and February, or heads in February. At the end of December, make a second sowing of baby lettuce mix, to harvest from late February to the end of March. Harvest leaves from the transplanted lettuce, and cut the first baby lettuce mix.

January: Use the “filler lettuce #2” to fill gaps in the lettuce beds up until January 25. After that is too late here for hoophouse lettuce planting, and we use spinach to fill all the gaps, regardless of the surrounding crop. Harvest leaves from the transplanted lettuce, and cut the first baby lettuce mix whenever it reaches the right size.

February: 2/1 sow the third baby lettuce mix, to provide up to three cuts, from mid-March to late April. In mid-February, consider a fourth sowing of baby lettuce mix, if outdoor conditions look likely to delay outdoor harvests. Harvest leaves from the transplanted lettuce, and cut the second baby lettuce mix when it sizes up. Harvest the first baby lettuce mix, clearing it at the end of February before it gets bitter.

March: Harvest leaves from the transplanted lettuce, and cut the second baby lettuce mix whenever it reaches size. Cut the third baby lettuce mix when it sizes up.

April: In the first half of the month, harvest the last of the transplanted lettuce as heads . Continue to cut the third baby lettuce mix until it gets bitter. Cut the fourth baby lettuce mix when it sizes up. Outdoor lettuce heads are usually ready for harvest mid-April. Plan to have enough hoophouse harvests until the outdoor harvests can take over.

Lettuce transplants in soil blocks, on our custom-made cart. We don’t use soil blocks for lettuce any more (too time-consuming!) but I love this photo. Photo Pam Dawling


The February issue of Growing for Market is out, including my article How to decide which crops to grow which I previewed some of here last August. I also included some of the material in my slideshow Diversify Your Vegetable Crops. Click the link to see the slideshow. This past winter we used this kind of process to reduce the amount of garden work for 2017. I’m retiring from garden management and the new managers  want to stay sane and not be exhausted all the time. We have fewer workers this year (the past few years actually), so we needed to slim down the garden and not go crazy trying to do everything we’ve done in the past. I’ll still be working in the hoophouse, the greenhouse, and doing some outdoor work, as well as being available to answer questions and provide some training when asked.

Back to Growing for Market. There’s a great article for new small-scale growers, from Katherine Cresswell in northern Idaho, Year One Decision Making, about starting a farm with only one implement. Careful planning lead Katherine and her partner Spencer to focus on fall, winter and spring vegetables, as no-one else around them provided these, and they had experience of winter growing from working on other farms. Clearly a high tunnel (hoophouse) needed to be in the plan. It was essential that they hit the ground running and have saleable produce within six months. The expense budget was very tight. They bought a BCS 739 walk-behind tractor (which they both had experience of) and a rotary plow. A very down-to-earth article to encourage any new grower with limited means.

There are reviews of three new books by GfM writers: Compact Farms by Josh Volk, Floret Farm’s Cut Flower Garden and The Greenhouse and Hoophouse Growers Handbook by Andrew Mefferd, the editor of GfM. Brett Grohsgal has written a valuable article about his 15 years experience with on-farm breeding of winter-hardy vegetables, both in the field and under protection of hoophouses. Informative and inspiring. Erin Benzakein has written about rudbeckias, the unsung heroes of summer bouquets, and Gretel Adams has written on new flower varieties to try in 2017.


I have a new post on the Mother Earth News Organic Gardening blog, Using Open Flats (Seed Trays) to Grow Sturdy Seedlings Easily – How to make reusable wood flats (seed trays) for seedlings, and use them to grow sturdy vegetable starts to transplant into your garden. This is a way to avoid contributing to the problem of agricultural plastic trash and be self-reliant in gardening equipment. You can also grow stronger plants by giving them a larger compost volume than plug flats or cell packs provide.

Open flat of broccoli seedlings.
Photo Wren Vile

I heard that my MEN blogpost Green Potato Myths and 10 Steps to Safe Potato Eating was very popular in January, coming sixth in their table of most-viewed posts on all topics. This has been out there in the blog-iverse for almost 18 months, so clearly there is a lot of concern about eating healthy food and not wasting what we’ve grown.

Sorting potatoes two weeks after harvest to remove problem potatoes before rot spreads.
Photo Wren Vile


The false spring has been barreling along. Last week I reported that we’ve seen a flowering crocus (2/17). Since then, we’ve seen daffodils and dandelions flowering, heard spring peppers and already the maple is flowering (2/25). These are all markers on our phenology list. The maple flowers on average 3/12, with a range (before this year) of 2/28 in 2012 to 4/2 in 2014. A 9-year record broken!