Success with Planting Sweet Corn

Success with Planting Sweet Corn

Sweet corn at sunrise.
Photo by Wren Vile

Very fresh home grown organic sweet corn is so delicious! There’s no denying that sweet corn takes up a lot of space, so if you are really short of land, you may decide to forego corn. On the other hand, corn doesn’t take a lot of work, so if you have the space, but are short of help, corn is a good choice. This information comes from my book, Sustainable Market Farming.

This post about sweet corn include an overview of our corn-growing, dealing with weeds, and my slideshow on Succession Planting

This one Growing Sweet Corn for the Whole Summer – Organic Gardening … is one I wrote for Mother Earth News Organic Gardening .

Don’t Set Yourself up for Failure – Understand Sweet Corn Genotypes

 You can skip this section if you are only growing one variety of sweet corn, no other kind of corn, and it is at least 250’ (76 m) from anybody else’s corn. Otherwise, before you plant (hopefully before you buy seeds), read this.

With most crops, cross-pollination with other varieties or types is only a problem for those growing seed. With sweet corn, the seed is the food crop. Failure to isolate genotypes can lead to starchy unpleasant-flavored corn. Hybrids are made by crossing OPs. Making hybrids does not involve genetic engineering!

Our late corn beside sweet potatoes.
Photo Ezra Freeman

Nearly all genotypes of hybrid sweet corn include one of two recessive genes, su or sh2. Cross-pollination with other corn groups will produce the dominant genetics of field corn (that starchy stuff!)

  1. Normal Sugary (su or ns) types of sweet corn have old-fashioned corn flavor but are sweeter than OPs, although the sweetness disappears fairly rapidly after harvest. Most can germinate well in cool soil.
  2. Sugary-enhanced (se) and Sugary Enhanced Homozygous (se+ or se-se) types are more tender than (su), and slower to become starchy after harvest. Most, especially the (se+) types, are sweeter than (su) types.
  3. TripleSweet Sugary Enhanced (se-se-se) corn was created to be sweeter than se-se.
  4. Super Sweet (sh2) (also known as Shrunken) varieties are very sweet and slow to become starchy. If not isolated from all other types of corn, they will be very starchy and disappointing. They have very poor cold soil germination. The kernels are smaller than other corns, giving this type its name. The seed needs careful handling, to prevent mashing between a seeder plate and the hopper.
  5. Synergistic (se-se-se-sh2) types are combinations of genetics from the 3 previous genotypes. Each ear has 75% (se) kernels and 25% (sh2) kernels. They are flavorful, tender and sweet, but only when they are ripe. If picked too soon, they are a watery disappointment.
  6. Augmented Shrunken: these newer types contain the sh2 gene and some of the tenderness from the se types.

Isolate these three categories by at least 250’ (76 m) from each other:

  1. Super Sweet/Shrunken sweet corn varieties (sh2);
  2. all other types of sweet corn;
  3. all other types of corn (eg popcorn, dent corn, field corn)

Instead, you can isolate by time, sowing on dates to achieve at least a 12-14 day gap between maturity of the different plantings.

Your neighbor’s GMO sweet corn will cross with your corn, if it’s close enough for the wind to bring the pollen in. “Bt corn” has been genetically modified by incorporating Bt genes (Bacillus thuringiensis) so the corn includes its own insecticide. There are many reasons not to grow GMOs, including the spread of random bits of genetic material by cross-pollination with previously non-GMO crops, and the likely consequence of Bt-resistant insects, so I won’t give them more space here.

Sweet Corn Varieties

Our first sweet corn of the season. Bodacious
Photo Pam Dawling

Most Open Pollinated (OP) sweet corns are noticeably less sweet than modern sweet corn, so consider hybrids. OP varieties also deteriorate faster after harvest than hybrids, becoming starchier. Luther Hill is said to be the sweetest OP variety.

Some catalogs  indicate which varieties are suitable for certain latitudes. (Corn flowering is day-length sensitive.) Johnnys has a “Dynamic Comparison Chart” for the sweet corn varieties they sell. Many companies run cold-germination testing, and can tell you which varieties that year have good potential for early sowings. Others can rot in cold wet soil.

We plant corn six times through the season, often with three varieties in each sowing, as shown here in our late corn.
Photo Kathryn Simmons

For our location, we rely on the first three genotypes, supplemented with some of the others for variety.

  • Bodacious, 77 day (se) yellow, great flavor for one this early;
  • Kandy Korn, 89 day (se) delicious yellow workhorse;
  • Silver Queen, 96 day (su) white long-time favorite with some drought-tolerance and insect resistance;
  • Luscious, 77 day (se-se-se) bicolor (organically grown, good cold soil emergence);
  • Tuxedo, 80 day (se) yellow (tightly-wrapped, earworm resistant);
  • Sugar Pearl, 72 day (se+) white (very early, on short plants);
  • Argent, 86 day (se) white (tasty with tight earworm-defeating husks);
  • Spring Treat, 66 day (se+) yellow, one of the earliest yellow sweet corns with good cold soil tolerance.
Silver Queen white corn when mature (with bug).
Photo Kathryn Simmons

Sweet Corn Crop Requirements

A pH of 6.0-6.5 is ideal. Very fertile soil is needed, including high phosphorus. P deficiency shows up as purple leaf tips and margins; N deficiency as pale spindly stalks, yellow leaf tips and shriveled kernel tips; Mg deficiency as white-yellow striping between veins, with older leaves reddish-purple, perhaps with dead tips. Corn is sensitive to deficiencies of zinc or copper, but less so to low levels of boron. When looking for deficiencies, it helps to know what is normal for that variety, and to also consider water shortage.

If you used legumes in the winter cover crop preceding your later sowings of corn, a good stand can provide all the nitrogen the corn needs (100-125 lbs/acre; 112-142kg/ha). When the legume reaches its flowering point, the nitrogen nodules on the roots contain the maximum nitrogen.

The number of rows of kernels on the cob is set five weeks after emergence (although each variety has a number that is usual, under good conditions). Ear length and number of plants with double ears is established nine weeks after emergence. There’s the feedback on your farm’s fertility plan.

Sweet corn needs warm soil. Catalogs usually indicate the soil temperature (measured at 9am) recommended for each variety. 50°F (10°C) is the absolute minimum, and applies to treated seed and OP or (su) varieties only. 60°F (15.5°C) is better for most, and 65°F (18°C) or higher is required by some varieties. Common phenology signs for the season being advanced enough to sow corn are that white oak leaves are the size of squirrels’ ears and that ragweed is germinating. For us the first corn sowing date is usually around April 26, which is also our average last frost date.

Corn has no tolerance of frost, but escape from a late spring frost is possible if the seedlings are less than two weeks old and not yet very tall, as the growing point may still be underground. Thus, in a spring that promises to be warm and dry, it is possible to risk an early planting as much as 2-3 weeks before the last frost date. Having some transplant plugs for a back-up helps reduce the risk level.

Emergence takes 22 days at 50°F (10°C), 12 days at 59°F (15°C), 7 days at 68°F (20°C), and 4 days at 77°F (25°C).       

Our third planting of sweet corn on the left, fourth in the middle, 5th (barely emerging) on the right.
Photo Pam Dawling

Sowing Sweet Corn

2oz/50’ (55gm/15m) or 1lb/400’ (370gm/100m) are generally required. The (sh2) types have more seeds for the weight, because the shrunken seeds are lighter than other types – 200/oz (7/gm), 2500-5500/lb (5600-12300/kg); 1lb/1250’ (118gm/100m).

Corn is usually grown in rows 36” (0.9m) apart. We sow fresh seed 6” (15cm) apart, and if using seed from the year before, we sow at 4” (10cm) apart.  Depth of sowing can vary with the soil temperature, being a very shallow 0.5” (1cm) in spring, to 1” (2.5cm) in summer when soils are warmer lower down and seeds benefit from the extra moisture.

Seedlings are thinned to 8-12” (20-30cm) apart. 8” (20cm) spacing is usually optimal in terms of using available light and maximum yield for the area.. Upper leaves get 7-9 times the light of lower leaves, therefore it is important that the upper leaves are in good condition, to photosynthesize well. The lower ones get much less light, so may be broken off for easier harvesting.

Young sweet corn plants after imperfect hoeing.
Photo Pam Dawling

Corn is wind pollinated (though you will find plenty of bees collecting pollen, regardless). For best pollination, plant in patches at least 4 rows wide. Inadequate pollination leads to ears with flat undeveloped patches among the kernels.

One of our sprinkler tripods, in a broccoli patch.
Photo Pam Dawling

Corn seed must have moisture to germinate. If you use a push seeder, irrigate after sowing. Because we sow small areas of many different varieties, and because people love to plant corn, we sow by hand. Our method has the advantage of delivering water right where the seed needs it. We measure and flag the rows, put out ropes on stakes along the rows, and make furrows (drills). The rope and its shadow make useful guides for keeping the rows straight. Next we have someone flood the drills with water from a hose, and we hand sow into the mud. After covering the seed and tamping the soil, we ignore the patch until the seed germinates. The watering in the furrow reliably provides enough moisture to get the plants up out of the ground. The ropes (about 12” (30 cm) above the ground) deter the crows, making it hard for them to land near the buried seeds. In recent years we have started using a seeder again, as the number of crows has worryingly declined.

We use overhead irrigation for corn. If you use drip tape, you might set out the tape, turn on the water for long enough to mark the soil with damp spots, then sow those spots with a jab planter.

Transplanting Sweet Corn

 It is quite possible to transplant sweet corn, so those in marginal climates don’t need to give up hope. We usually prepare some plugs the same day we sow our first corn outdoors and use these to fill gaps at the first cultivation. We use 200-cell Styrofoam Speedling flats (1”, 2.5 cm cells). We float these in a tank of water until we set them out. Some vegetable seedlings would drown if continuously in water, but corn does not. It is important to transplant the corn before the plant gets too big, and the taproot takes off. 2″-3” (5-7.5 cm) plants seem OK. The plugs transplant easily using butter knives.

I’ll write about Growing Great Sweet Corn in about a month.

 

Workhorse Crops for May

Young bush bean plants.
Photo Pam Dawling

Workhorse Crops for May

Workhorses crops are reliable under a wide range of conditions, including weather, soil, date and other variables. Some are easy to grow, some pump out lots of food, some are “insurance crops” like chard that stand in your garden until you need to harvest them, some are especially profitable (for those growing for market).

I’ve chosen 14 crops (including two pairs) to focus on in the next 12 months, ending April 2022: Asparagus, beans, cabbage, carrots, chard, garlic, kale and collards, potatoes, sweet corn, sweet potatoes, tomatoes, watermelons, winter squash, zucchini and summer squash.

My motivation for this series is to help all who want to be more efficient, productive and profitable (if selling) as other parts of our lives expand again.

Workhorse Crops to Plant in May

May is a busy planting month here in central Virginia and probably most places in the northern hemisphere. Ten of our 14 Workhorse Crops can be planted once frosts are behind us.

Beans: We grow bush beans because we don’t like putting up trellises. In the past we had uncontrolled Mexican Bean Beetles that destroyed slower-to-mature pole beans. We found we could get crops of bush beans faster and sow them every few weeks or so to get a good supply of presentable beans every couple of days. Click this link to read about soaking bean seed, using inoculant, sowing through biodegradable plastic mulch using a jig, sowing sunflowers in our bean rows as place-markers when harvesting. See my phenology post for information on when it’s warm enough to start sowing beans (and other crops) where you are.

Carrots: I wrote a lot about carrots in the past year, when the monthly series was on root crops. See this post on preparing beds for sowing carrots, and weeding and thinning. Check out this post on flame-weeding, if you plan lots of carrot-growing!

Multicolored chard. Wren Vile

Chard: A great insurance crop – it provides leafy greens when you need them, and you can ignore it when you have plenty of other vegetables! As a biennial, chard will not bolt the first year (unless stressed by lack of water). We use chard for fresh greens in summer, when kale, collards, broccoli and cabbage from the spring have long gone. Because we don’t need chard until late May, we don’t sow until late March. We transplant in late April, into a hay mulch. This crop will be in the ground until mid-winter, and mulch will keep back most of the weeds. You could, of course, sow chard earlier if you want to eat it earlier. We also grow chard through the winter in our hoophouse, where it feeds us during the Hungry Gap.

Potatoes: I wrote a special series on potatoes last year. Click the link to access the whole series, starting with planting in April. Here we plant in March and June. You can plant at any date in between, so long as you have 80 days until your first frost. If time is a bit short, choose a fast-maturing variety (or be satisfied with small potatoes that won’t store).

Sweet corn: we make 6 sowings of sweet corn, to harvest from July 4 to mid-October. Start planting sweet corn when the leaves of the white oak are as big as squirrel’s ears. Click the link to check our planting dates, and to read about our first sowing of the year, catching raccoons and skunks, avoiding mixing types of corn and to view my slide show on succession planting. There’s a confusing aspect of hybrid corn varieties: if you plant a mixture of different genotypes, it can lead to starchy unpleasant-flavored corn. Also don’t plant Indian corn, popcorn or any kind of flint or dent corn within 600′ (180 m) of your sweet corn. For this reason we grow only sweet corn in our garden.

Our first sweet corn of the season.
Photo Pam Dawling

Sweet potatoes: I wrote about planting sweet potatoes in 2020. Modern varieties of sweet potatoes grow to a good size in as little as 90 days, so they are not just for the South! The further north you are, the longer the daylight at midsummer and the more photosynthesizing the plants can do. I have known people grow sweet potatoes in hoophouses if their climate isn’t warm enough outdoors. This can fit with winter use of the hoophouse for greens and roots. My book Sustainable Market Farming contains a whole chapter on this crop, including growing your own slips, but it’s too late to start that this year. Wait for the soil to warm before planting out your sweet potato slips. We plant ours a couple of weeks after the last frost, around the time we transplant peppers and okra.

Tomatoes: We plant out our main crop at the very beginning of May, unless the weather is too cold. To my surprise, I find I haven’t written much about transplanting tomatoes outdoors. Here’s a post about planting tomatoes in our hoophouse. We use the same techniques in the hoophouse and outdoors. We transplant one row of tomatoes down the centerline of a 4ft (1.2 m) bed, 2ft (60 cm) apart. Outdoors, once the weather has settled so that we’re confident we won’t need rowcover any more, we stake and stringweave. We install a steel T-post every two plants (4ft /1.2 m) apart and start stringweaving when the plants are about 12ins (30 cm) tall. I’ll say more about stringweaving later in the year.

Watermelon transplants in a Winstrip plug flat. Watermelons give earlier harvests from transplants, and plants in plug flats transplant easier then from open flats.
Photo Pam Dawling

Watermelons: Watermelon growing isn’t easy, but the rewards are so wonderful, that I gave watermelon a “Circus Pony” place among the workhorses! We transplant our watermelons, to get ripe ones as early as possible. Melons are tricky to transplant, as the roots don’t do well if disturbed. We have successfully used soil blocks, and these days we use Winstrip 50-cell trays. Watermelons grow very well on black plastic mulch, which warms the soil as well as keeping weeds at bay. The first year we switched from using hay mulch to biodegradable plastic mulch, we were astounded to get ripe melons a full month earlier!

It’s important to keep the little seedlings in the greenhouse warm and in very good light, and away from drafts. Be careful not to overwater. They can keel over very quickly and once the stem collapses, remove that seedling before others die too. The goal is short stems!

When you transplant, get the start out of the flat and into the ground as quickly as possible with as little root damage as you can manage. This is not a crop where one person plops the plants out down the bed and someone follows planting them! Make the hole in the soil (through the plastic if you’re using that), by wiggling the trowel from side to side. Don’t dig a hole as if you are in a sand box, with a spoil heap at the side. Just form a space the right depth to get the whole of the stem in the ground.

Next gently pop the transplant out of the flat, perhaps using a table knife down the side of the cell. Push up from underneath. If all goes well, you’ll have the plant in a little block of soil (yes, like a soil block). Slide the transplant into the hole. You want all the leaves above ground, all the roots and stem in the ground. If the hole is too deep, lift the transplant carefully and scrape some soil into the hole. You don’t want to end up with the plant in a dip, as this can rot the stem. If the hole is not deep enough, you can to some extent hill up soil around the stem to protect it. You don’t want any of that fragile stem visible!

Water the day before, and one hour before transplanting, to help the soil hold together, and so that the plant has some reserves of water to see it through the initial shock of being set out. As you are transplanting, pause and water newly set plants every 20 minutes or so. Afterwards, water the whole planting and repeat on the 2nd, 3rd, 5th, 7th days and once a week after that.

Winter squash: By contrast, winter squash are very easy, and they store for months at room temperature. A true workhorse. We direct sow at the end of May, with the goal of harvesting in September and October, the last ones making Halloween lanterns. Soil should be at least 60°F (15.5°C), and all danger of frost should be past.

Young squash plant.
Pam Dawling

We have grown about 400ft (120 m) for 100 people, and mostly focus on Butternuts, Moschata types that grow best where we are and store longest. This is the type to focus on if you want trouble-free squash, with no damage from borers or cucumber beetles. The tougher stems are better able to repel invaders. They need warm growing temperatures above 60°F (16°C). As well as Waltham Butternuts, we include the large Cheese pumpkin, the long-storing Seminole, and the gigantic Tahitian Butternut. We also grow a couple of Maxima squashes which store quite well:  Cha-cha kabocha, and the large blue Jarrahdale, which have relatively high resistance to squash bugs compared to others in this group. Red Kuri, Festival (sweet dumpling type) and the New England Pie pumpkin are Pepo squashes, suitable for storing a few weeks only. (Pumpkins are squashes.) We grow some of these because they are sooner to harvest. Really they are more of a fall squash than a winter squash.

Winter squash do need a lot of space for each plant. This can mean a lot of hoeing until the vines spread, or mulch. Some can take 90-120 days to reach maturity, so plan carefully to be sure of getting a harvest. For dryland farming, without irrigation, it is important not to move the vines to new positions: the dew and rain drips from the leaf edges encourage root growth directly below the vines (where they get the most water and shade).

Sow 0.5”-1” (1-2 cm) deep. Either “station sow” 2 or 3 seeds at the desired final spacing, or make a drill and sow seeds 6” (15 cm) apart. There are various stick planters and jab planters that can be used for this kind of station sowing. Thin later. Rows will need to be 6’ (1.8 m) apart, or more. 9’ (2.7 m) between rows for the vining ones. Some growers plant in a square pattern so that spaces between rows can be mechanically cultivated in both directions. Bush varieties take less space than the vining types, and rows can be 4’ (1.2 m) apart.

You can transplant winter squash if you need to. We did this one year after our fields flooded. We started seeds in cell packs a week before our usual sowing date of 5/25. It worked just fine.

Summer squash plants under insect netting.
Pam Dawling

Zucchini (courgettes) and summer squash: Zucchini is a subset of summer squash. These are easy to grow, fast to produce warm weather crops. We make a succession of five or six plantings each year, so that we can harvest every day. Each sowing is half a yellow squash (Zephyr, Gentry) and half a zucchini (TenderGrey, Noche, Golden Glory). We grow our earliest squash in the hoophouse, setting out transplants at the beginning of April. Our first outdoor crop is also from transplants. After that, the soil is warm enough to direct sow – 60°F (15.5°C).

After transplanting or sowing, we hoop and cover the row with insect netting (rowcover also works if it has no big holes). We have many bugs that like these plants, especially the striped cucumber beetles, so we keep the rows covered until female flowers appear. At that point we need the service of the pollinators, unless the squash is parthenocarpic (sets fruit without pollination). At that point we pack away the covers, hoe and thin the squash to 24” (60 cm). it would be better to thin sooner, but we rarely find the time.

Zucchini and summer squash are another crop type that we succession sow, to get a continuous supply. More about succession planting another time. The time from sowing to harvest is only around 50 days.

Workhorse Crops to Harvest in May

Asparagus photo by Kathryn Simmons

Asparagus can be harvested if you have a patch. If not start to prepare a patch to plant out one-year crowns next early spring. Remove all perennial weeds while growing a series of cover crops. If you have asparagus, you probably know to snap off at ground level all the spears above a certain length. We chose 7” (18 cm). Do this every day for the 8-week harvest period. Daily harvest will also remove asparagus beetle eggs, controlling the pest level.

A bed of Early Jersey Wakefield cabbage in mid-May.
Photo Pam Dawling

Cabbage can be ready from late May, if you made an early sowing of fast-maturing varieties. Farao or Early Jersey Wakefield can take only 60 days.

Carrots can be ready from late May, if you sowed some in mid-late February

Chard is ready for harvest from late May (earlier if sown earlier), see above.

Harvesting garlic scapes in May
Photo by Wren Vile

Garlic scapes appear in hardneck garlic plants. Here it is also an indicator that our garlic will be ready to harvest in three weeks.

Kale and collards can be harvested until they are bolting, as long as the flavor is acceptable. Read more about bolting here.

Zucchini and summer squash from mid-May,

From storage: carrots, potatoes, sweet potatoes, winter squash

Workhorse Crops Special Topic: Deciding Which Vegetable Crops to Grow

Here’s a slideshow to help you decide which crops to grow. Some of the points are for commercial growers, some apply to anyone growing vegetable crops.

Deciding Which Vegetable Crops to Grow, Pam Dawling

Modern Homesteading Interview, Things I’ve Changed My Mind On

Hoophouse squash, tomatoes, and cucumbers.
Photo Alexis Yamashito

In April I did a pleasant phone interview with Harold Thornbro of the Modern Homesteading Podcast  about how year round gardening in a hoophouse can increase yields and the quality of vegetables and extend the growing season.

You can listen to it here:

https://www.stitcher.com/podcast/modern-homesteading-podcast/e/60326060?autoplay=true

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The rest of this post is about the agricultural things I’ve changed my mind on in recent years.

Sowing Leeks
Leek seedlings growing in an outdoor nursery bed.
Photo Kathryn Simmons

The first one that comes to mind is where and how to sow leeks. In Sustainable Market Farming I describe sowing leeks in outdoor nursery seedbeds. We grow leeks for eating from October to March, so even though leeks grow very slowly and need 12 weeks to transplant size, we don’t need to sow them super early in the year. Also because they are so cold-hardy, they don’t need greenhouse conditions. To save greenhouse space, and the bother of watering so many flats, we took to sowing them outdoors. To make this work, you do need weed-free beds. Leeks compete poorly with weeds. Sometimes things went wrong. One year someone decided to “seed-bomb” the fresh bed with poppy seeds. Weeding those tiny leek seedlings was torture! Another time, an overenthusiastic worker ran our new exciting wheel hoe too far onto the bed and eradicated part of a row.

Leek seedlings in flats in April.
Photo Pam Dawling

One year the leek seedling bed wasn’t ready in time to sow, and we sowed rows of seeds in a coldframe, after removing the winter spinach (or maybe we were still growing lettuce in the coldframes then.) This worked well. The next year we tried sowing the seeds in 4” (10cm) deep flats, and putting the flats into the coldframes right away (rather than germinating them in the greenhouse). Still no wasted greenhouse space! On very cold nights, we cover the coldframes, so it was a bit warmer than if we’d just sowed directly into an outdoor bed. The plants grew a bit quicker and we realized we didn’t need to start so early. They were easier to take to the field in the flats, compared to digging up the starts and carrying them in little buckets with water. We had reduced losses of seedlings, so we reduced the amount of seed sown in future years. It’s an easier system, with a more satisfying success rate.

Sunnhemp as a Cover Crop
Sunnhemp cover crop at Nourishing Acres Farm, NC.
Photo Pam Dawling

 Sunnhemp (Crotalaria juncea) is a warm weather leguminous cover crop that I’ve been admiring at various farms in the Southeast in recent years. I’ve been thinking it would be valuable ion our hoophouse and in our gardens. It fights root knot nematodes! I mentioned it recently at a crew meeting, only to be reminded that I previously spoke against growing it as the seed is poisonous! I’d completely forgotten my earlier opinion!

This summer cover crop can grow to 6’ (2m) in 60 days. It thrives in heat, tolerates drought, fixes nitrogen, suppresses nematodes, makes deep roots that pull nutrients from deep in the soil, and it dies with frost. It sounds fantastic, I really want to try it!  It looks a bit like small sunflowers, and according to Southern Exposure Seed Exchange  it  won’t make mature seed above 28 degrees N latitude , so won’t become a self-sowing invasive  in Virginia. Sow in rows 2’-3’ (0.6-1m) apart. If it gets too big, mow when plants reach 5’-8’ (1.5-2.5m) to prevent the stalks from becoming tough and hard to deal with. ¼ lb sows 250 sq ft. (¼ lb = 114 g, 250 sq ft = 23.2m2)

Sowing Sweet Corn
Young sweet corn with a sprinkler for overhead watering.
Photo Bridget Aleshire

I mentioned earlier here, that I’ve changed my mind about the necessity to put up ropes over corn seed rows to keep the crows off. I suppose there are fewer crows these days, sigh. Not needing the ropes makes the benefits of sowing with the seeder greater than the benefits of sowing by hand, so long as we can irrigate sufficiently to get the seed germinated. When we sowed by hand we watered the furrows generously, which meant we did not need to water again until after the seedlings emerged. If we hit a serious drought, the old method could still be best. Overhead watering does germinate lots of weeds, including in the wide spaces between the corn rows, so we need to factor in the extra hoeing or tilling when we weigh up the pros and cons. So, I’m a “situational convert” on this question!

How to Kill Striped Cucumber Beetles
Striped cucumber beetle in squash flower.
Photo Pam Dawling

I wrote about these beasties here. We handpick the beetles in the hoophouse squash flowers, hoping to deal with the early generation and reduce future numbers. One year we had our first outdoor squash bed very close to the hoophouse and the beetles moved there. In desperation I used Spinosad, an organically approved pesticide. It is a rather general pesticide, and harms bees, so I carefully sprayed late in the day and covered the row with netting to keep bees off. It worked brilliantly, taking a fraction of the time that daily handpicking takes. I became a convert to that method, but no one else on the crew did, so we went back to hand-picking.

Pruning Tomatoes
Hoophouse tomatoes in early May
Photo Bridget Aleshire

I used to maintain that life is too short to prune tomatoes, which grow at a rapid rate in our climate, and get fungal diseases, necessitating sowing succession crops. The past couple of years I have removed lower leaves touching the soil, and this year I reduced the sideshoots on our hoophouse tomatoes, which are grown as an early crop here.(We’re about to pull them up in early August, as the outdoor ones are now providing enough). I do think we got fewer fungal diseases, and the diseases started later compared to other years, so I am now convinced that removing the lower leaves is very worthwhile. We also got bigger fruit this year, which logically fits with reducing the foliage some amount.

Is There Such a Thing as Too Much Compost?
Too much compost?? A commercial compost windrow turner.
Photo by Pam Dawling

I used to think the more compost the better. Now I am more aware that compost adds to the phosphorus level in the soil. I wrote about that here. I am not as alarmist as some people about high P in our situation, but I do now think it is worth paying attention and not letting the levels build too fast. I have got more enthusiastic about growing cover crops at every opportunity, and finding legumes to include in cover crop mixtures at every time of year (see above about sunnhemp). I was already a cover crop enthusiast, but as my experience increased, I got my mind round more possibilities.

Using Plastics
Rolling biodegradable plastic mulch by hand
Photo Wren Vile

In my youth I was anti-plastic, If I were growing food just to feed myself, I’d probably still find ways to avoid almost all plastics, but growing on a commercial/professional scale (and getting older) has led me to appreciate plastics. I still don’t want to do plastic mulch, except the biodegradable kind, but I’ve come to accept durable light weight plastics for their benefits. Drip tape saves do much water, reduces weed growth. Plastic pots and flats are so much easier to lift! I do still pay attention and try to make plastics last a long time, and frequently salvage plastic containers others discard. I’m awed by the possibilities of silage tarps or old advertising banners, to keep down weeds without tilling and pre-germinate weed seeds so that when the covers are removed, few weeds grow. This was called by the awkward name of “occultation”, but is now more often referred to in English as tarping.

Hornworms

Lastly, I have a post on Mother Earth News Organic Gardening about hornworms, but you read it here first!

Sweet corn, potatoes and okra

Our first sweet corn of the season (Bodacious).
Photo Pam Dawling

Sweet Corn

We sowed our first sweet corn on 4/18, eight days earlier than usual this year, because we had auspicious weather. We look at the leaves of the white oaks to decide when it is warm enough for corn planting. The oak leaves should be as big as squirrel’s ears. Phenology signs like this are especially useful when the weather is extremely variable, which we are getting more of as climate disruption has got us in its grip.

Our first sweet corn sowing is always a bit of a risk. In fact we often prepare for this by sowing some corn seeds in styrofoam Speedling flats, the same day we sow the first corn planting outdoors. Read more about this seedling technique and transplanting corn.

Our third planting of sweet corn on the left, fourth in the middle, 5th (barely emerging) on the right.
Photo Pam Dawling

We’ve been harvesting sweet corn since July 2, which is two days earlier than our target start date, so we’re very happy. Initially, of course, we got smaller amounts, but we are now harvesting three times a week and getting good amounts. We are back up to 6 sowings this year, after we had to cut back for a couple of years. For a hundred people we sow an average of 1100 ft (335m) each time we plant, with each planting intended to last us 15 days (7 or 8 pickings). Our goal is sweet corn from July 4 to mid-October (our average first frost is October 20, a 13 year average from our own records).

Three varieties of sweet corn in one planting. On the left Bodacious; in the middle, red-flowered Kandy Korn; on the right, Silver Queen not yet fully grown.
Photo Kathryn Simmons

Each sowing includes several varieties (with different numbers of days to maturity) on the same day, so a planting will give us at least two weeks of delicious corn. In this photo from a previous year, you can see (from left to right): later-maturing Silver Queen, not yet at full height; red-flowered Kandy Korn; fast-maturing shorter Bodacious. Each plant is only going to provide two or three ears, so to have enough, and to have a continuous supply, it is necessary to plan ahead. See the Succession Planting section ahead.

Sowing sweet corn

We have switched to sowing corn with the EarthWay seeder, with a homemade next-row marker. This is much quicker than sowing by hand, but does rely on providing overhead irrigation consistently until the seedlings emerge. Another trade-off is that we get more weeds germinating in the (watered) aisles than we did when we only watered the furrows at planting time. Drip irrigation would be another approach.  So far we have not lost corn to crows, which was the reason we took to the handsowing-under-ropes method some 20 years ago. Back then we also sowed our fist corn with a tractor seeder, but we had to follow that with putting up ropes, or we lost it all to birds. Details of our hand-sowing method are in this post from May 2016.

Staying on top of weeds in the sweet corn

Once we get to late June, more of our time in the garden is taken up by harvesting (a sign of success), leaving less time for weeding. We have a system I like that helps us stay on top of sweet corn weeds. Each time we sow sweet corn, we hoe the previous planting (about two weeks old), thin the plants to one every 8″-12″ (20-30cm) in the row, and wheel hoe or till between the rows. We have two Valley Oak wheel hoes that we really like. The handle height is adjustable and they are available with different width hoes (and other attachments). Our tiller is a BCS 732 from Earth Tools BCS

Don’t let this happen to you! Weedy young corn.
Photo by Bridget Aleshire

We also hoe the rows of the corn planting before that one (about 4 weeks old), and till between those rows and broadcast soybeans (which we till in lightly). Soybeans will grow in partial shade, handle the foot traffic of harvesting, and provide some nitrogen for the soil. For the last corn of the season, we undersow with a mix of soy and oats. After the harvest ends, we leave the patch alone, and the oats survive the first frosts (which kill the corn and the soy) and go on to be our winter cover crop for that plot. When it gets cold enough, the oats do die, and the plot becomes an easy one to bush hog and disk in the early spring for our March-planted potato crop. I like that opportunity to eliminate one round of disking, and to get a winter-killed cover crop established

As we harvest corn we pull out any pigweed that has somehow survived our earlier efforts. I learned at a Sustainable Weed Management workshop, that pigweed puts out its seeds in one big bang at the end, so pulling up huge pigweed is worthwhile, if it hasn’t yet seeded. (Actually you can see it for yourself, but before the workshop I hadn’t noticed!) Our soil has improved over the years, so it is now possible to uproot 5ft (1.5 m) pigweeds. Sometimes we have to hold the corn plant down with our feet, but we do almost always succeed in getting the weeds out, without damaging the corn.

Succession Planting for Sweet Corn

In Sustainable Market Farming I have a chapter on succession planting, and my slideshow on Succession Planting is one of my most popular ones. You can watch it right here.

I posted on Mother Earth News Organic Gardening blog about Growing Sweet Corn for the Whole Summer. You can read it here:

Growing Sweet Corn for the Whole Summer – Organic Gardening

Our sweet corn sowing dates and harvests from those plantings are

  1. 4/26, harvest 7/9 (with a few ears from 7/4)
  2. 5/19, harvest 7/24
  3. 6/6, harvest 8/8
  4. 6/24, harvest 8/23
  5. 7/7, harvest 9/7
  6. 7/16, harvest 9/22

Avoid mixing types of corn.

There’s a confusing aspect of hybrid corn varieties: There are several genotypes, and if you inadvertently plant a mixture of different types, it can lead to starchy unpleasant-flavored corn. Also don’t plant Indian corn, popcorn or any kind of flint or dent corn within 600′ (180 m) of your sweet corn. For this reason we grow only sweet corn in our garden. Ignore those cryptic catalog notes at your peril!

Dealing with raccoons, skunks and curious cats in the corn

We have trapped (and then killed) raccoons in our corn most years, and the past few years we’ve tried deterring them with nightly radio broadcasts. We have the large live mammal traps, and we found for raccoons, we needed to stake the trap down to the ground. I followed suggestions from Joanna Reuter of Chert Hollow Farm, staking the traps down and smearing peanut butter high on the stake in the back of the cage. Well, the first morning I caught a small, very white skunk! I let it out carefully. The next morning I caught the same skunk again. And the third morning, again. You can read more about how I let the skunks out. I’ve also caught some of our cats by accident.

Raccoons don’t seem to like Silver Queen as much as Kandy Korn, maybe because the husks are tighter and harder to rip off. Actually I like Kandy Korn better than Silver Queen too.

Okra

Cow Horn okra flower and pod.
Photo Pam Dawling

We have started harvesting our okra. It’s a little later than it might have been because we had to replant. The first planting had leggy seedlings due to not enough light soon enough in their lives. Then we planted it out with novice helpers, and they didn’t plant them deep enough. The feeble stems couldn’t take it. We made an attempt to hill them up to give more protection to the stems. Another mistake we made was over-watering. When we pulled up some of the dead plants for our postmortem, they reminded me of retted flax stems – the fibers were still there, with the soft tissue rotted away. This is why I think the problem is that we over watered rather than under-watered.

This year we are trying Carmine Splendor, a red okra from Johnny’s, as well as our usual favorite Cow Horn from Southern Exposure.

Cow Horn okra pods.
Photo Bridget Aleshire

We like Cow Horn for its tall plants, high productivity and the fact that the pods can get relatively large without getting fibrous. They are still tender at 5-6″, which is the size we used to harvest at. Some years we have attached a card to the handles of the pruners we use for this job, with a life-size drawing of a 5″ pod. This helps new crew get it right.

We do find it very hard to convince our cooks that we have specially chosen this “commune-friendly” variety so they don’t have to deal with fiddly little okra pods when cooking for 100. We’ve had to compromise and harvest at 4″. Hence the venturing-out to another variety, accepting people are hard to convince about Cow Horn!

We grow a 90′ row, with plants about 18″ apart in the row. This is enough for the hundred of us (some people never eat okra despite the cooks’ best efforts!)

Carmine Splendot okra plant.
Photo Pam Dawling

Carmine Splendor is a 51 day (from transplanting) F1 hybrid, with sturdy 5-sided pods that are deep red when small. I haven’t tasted them yet.

Potatoes

June-planted potatoes emerging from mulch in mid-July.
photo Pam Dawling

Our June-planted potatoes are starting to come up through the hay mulch, and we need to walk through and free the trapped shoots. This means we walk through investigating the spots where we expect there to be a potato plant but we don’t see one. If we find a trapped shoot, we open up the mulch to let the plant see the light. We do this same job with garlic in late November or early December.

This week we are harvesting our March planted potatoes. I just dug 30lbs for tonight’s dinner. Yes, lots of diners! The rest of the crop will be harvested using a digging machine on Thursday.

We harvested our March-planted potatoes 21 days ago, and we are in the process of sorting them and managing conditions in our root cellar to cure the potatoes and help them store well.

Crates of potatoes in our root cellar.
Photo Nina Gentle
Click here for our Root Cellar Warden” instructions from last year.

Dormancy Requirements of Potatoes

We are researching 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.

Tobacco Hornworm pupa

Just had to add this, which I dug up yesterday. These brutes are about 2″ (5 cm) long. They are heavy and they move slightly. Also, check out the comments on the last post and be sure to see SESE’s Ken Bezilla’s Instagram of a hornworm in black light.

This is the pupa of the tobacco hornworm.
Photo Pam Dawling