|‘Graffiti’ (top left), ‘Amazing’ (right) and ‘Cheddar’ cauliflower. Hutton says that ‘Cheddar’ is by far the favorite with the crew at Monmouth. Photo courtesy of Mark Hutton.|
The Maine climate is great for producing brassicas. At the 2007 Farmer-to-Farmer Conference, Mark Hutton of the University of Maine Cooperative Extension’s Highmoor Farm in Monmouth and Jason Kafka of Checkerberry Farm in Parkman covered production methods for organic growers.
Hutton gave a brief history of the Brassica genus, noting that cabbages and kales, the first brassicas to be domesticated, probably came from the North Sea area of northern Europe, where they derived from wild sea kale (Brassica oleracea var. sylvestris), which still grows there. Heading forms emerged about 1616. Cauliflower developed in Cypress or the area near Jerusalem and Syria around 1490. Broccoli probably predates cauliflower, with some broccoli raab going back to the 1400s in Italy, and some to Roman times.
Brassicas were widely cultivated in Colonial America (see “Brassicas”), but more as food for animals than humans. For human consumption, they were called “pottages,” because they were diced and thrown in a pot to boil with other vegetables. For animals, they were grazed in the field or cut and stored for winter.
“Cole” originates from the Latin caulis, meaning “stem” or “stalk,” and “cole crops” generally refers to the stem or stalk brassicas (cabbage, cauliflower, broccoli, brussels sprouts, kohlrabi – and kale, which is still Brassica oleracea), rather than the leafy types, such as collards.
|Maine’s climate is great for growing heading brassicas, such as broccoli. Photo courtesy of Mark Hutton.|
Nutrient Needs and Deficiency Symptoms
These plants generally are heavy feeders, although their nitrogen (N) needs vary widely. For early cabbage and broccoli, the necessary N can be supplied at planting time, and sidedressing is rarely needed. In fact, head rot can be a problem if excess N is supplied to broccoli.
Brassicas usually take up about 160 lbs./A of N, but this will vary with soils. Most N (100 lbs.) is broadcast and incorporated before planting; main or late-season crops may be sidedressed after three or four weeks with about 60 lbs. of N (or about half that for cauliflower), although Hutton noted that in organic systems, most of the N will probably come from manure, cover crops or compost, so most of the needed N would be in the ground at planting.
These brassicas need about 200 lbs. of phosphorus (P2O5) per acre; and about 175 pounds of potassium (K2O).
Phosphorus needs to be in the soil before planting; sidedressing is impractical with the element, since it is so immobile in soils. If using transplants, starter solution, such as fish emulsion, can supply the necessary phosphorus. Deficiency symptoms include purpling of the oldest leaves first.
Potassium deficiency first appears as puckering on the oldest leaves, which will be limp and have a dull sheen. Most Maine soils have enough K, and excess K can lead to tipburn, because K competes with calcium (Ca) for uptake by the plant.
Magnesium (Mg) deficiencies – fairly common in cole crops, especially in lighter soils – can be corrected by using dolomitic lime, if the soil pH needs to be raised; or through foliar application of Epsom salts (about 2 1/2 lbs./A) as a solution.
Calcium deficiency in small plants results in upwardly cupped leaves and, later in the season, when it’s too late to remedy, tipburn. The balance of Mg, manganese (Mn) and K affects Ca uptake, and that balance – and how much Ca needs to be applied – depends on the soil pH and cation exchange capacity.
Of all the crops that Maine growers raise, the cole crops have the highest requirements for sulfur (S), which occurs in glucosinolates (secondary compounds that plants produce for protection against pests; and that have cancer-fighting properties in humans). Most Maine soils have enough S, unless brassicas are cropped repeatedly on light soil. Cauliflower is more susceptible to S deficiency than other cole crops, with a deficiency showing up as yellowed foliage, stunting and, late in the season, small heads lacking quality.
Boron (B) deficiency can cause hollow heart (a hollow area in the stem); corky, discolored areas on the stem; and browning in heads and curds. Hollow stem due to B deficiency causes black, callused, necrotic regions within the hollow; while uneven or too rapid growth (from excess N or water, for example) can cause a hollow, nondiscolored area in the stem that is not due to B deficiency. On high pH soils, apply about 3 lbs./A of B from borox or Solubor to remedy B deficiency; or use a liquid, foliar feed – but use caution; it is easy to oversupply B. Manure and compost also supply boron.
Molybdenum (Mo) deficiency will be very obvious as whiptail – i.e., constricted, whip-shaped leaves. Hutton has seen this, but it’s usually spotty due to a bad area in the field and is rare in fertile soils. Cauliflower, broccoli and brussels sprouts have more Mo problems than does cabbage.
|Broccoli seedlings grown in an organic, compost-based mix (seedlings in back) grew faster than the same varieties (‘Gypsy’ and ‘Arcadia’) grown in a conventional seed starting mix (in front). The conventional plants caught up with the organic once in the field. Photo courtesy of Mark Hutton.|
Most of these deficiencies won’t be seen in organic systems, where soils are enriched with composts, manures and green manures.
Brassicas germinate best at 55 to 65 degrees but can go up to 75 degrees. Five- to six-week-old transplants are required for early spring production. For direct sowing, wait until soil temperatures are about 65 degrees. Hutton often direct seeds late summer and fall crops. The soil should be moist enough for germination; and seeds should be planted 1/2- to 3/4-inch deep. “They’re puny little seeds,” said Hutton. “They don’t have much energy reserve to get out of the ground.” Keep the soil from crusting by keeping it moist with irrigation so that seedlings can emerge.
Direct-seeded stands usually have to be thinned, unless coated seeds or a precise seeder have been used.
Hutton grew the same variety of transplant in a conventional plug mix and in a compost plug mix from Living Acres and saw “amazing differences”: The organic seedling was significantly larger. Once in the field, conventional plants caught up with organic, but the bigger, organic plants were easier to get through the transplanter.
Spacing depends on the variety, the market and your equipment, but Hutton gave the following general recommendations:
|Crop||Inches between rows||Inches apart within rows|
|Cabbage – fresh market
||24 to 36||10 to 14|
| Cabbage – kraut/storage
||24 to 36||18 to 24|
| Broccoli – field seeded
||3-4 rows/bed at 17” apart||7 to 10|
| Broccoli – transplants
||24 to 36||12 to 18|
||34 to 36||15 to 18|
|Brussels sprouts||34 to 48||24|
“Optimize the density so that plant growth isn’t hindered but plants grow quickly enough to shade out weeds,” said Hutton, adding that crowding sacrifices size only. A storage cabbage that is supposed to grow at a 24- x 24-inch spacing but is on a 24- x 14-inch spacing may be smaller. For instance, a variety normally producing a 35-pound head may make only a 20-pound head. “You can play around with plant spacings to get the size of marketable crop you want – except for brussels sprouts,” said Hutton, which need to be planted at the recommended spacing for the variety to ensure good air flow and produce quality, disease-free sprouts.
Cabbages can be green, red or some color in between; and they can be grown for the fresh market or for storage or processing. Fresh market cabbage can mature as fast as 56 to 60 days; some storage cabbages take 150 days, some even longer; these are big heads that will keep for eight months. Early, fresh market cabbage tends to have a softer, less leathery leaf and tends to be higher in sugars and lower in glucosinolates (which give a mustardy, hot taste to storage or processing cabbages).
Most brussels sprouts are grown from transplants, because they take 95 to 120 days to mature. Hutton said to top them when plants are about 18 inches tall and sprouts are about 1/2 inch in diameter. Topping means removing the tip of the plant to encourage production of more, larger sprouts (axillary buds) all at one time. At the same time, snap or cut leaves from the lower half of the plant to promote air movement. Diane Schivera of MOFGA noted that the removed tops are edible. Hutton added that home gardeners may not want to top plants if they want sprout production over a longer time – although Grower Jan Goranson noted that topping is very important for commercial growers, to get sizeable sprouts.
Common Insect Pests
Hutton noted the following about potential brassica pests.
Cabbage maggot – The adult fly is about half the size of a common house fly and a little darker in color. Two or three generations a year occur in Maine. The first adults emerge when yellow mustard and Amalanchier start to bloom. Adults lay eggs at the base of stems, and larvae feed on roots. Controls include row covers over plants and straw mulches around the base of plants. Soils high in organic matter attract the flies.
Imported cabbageworm adults are beautiful white butterflies with black spots. The velvety green worm feeds on plant tops. Cabbage looper worms are less velvety, have yellow stripes along their sides, and form a loop (like an inchworm) when the move. Protect plants with row covers or spray with Bt or Spinosad products. The action threshold is about 30 plants with one or more medium to large worms or loopers. The threshold is 10 once cabbages reach the cupping stage and begin to form a head. The first and second instar larvae are most susceptible to sprays; try to get the best coverage possible.
Diamondback moth larvae have developed resistance to Bt products, so can be hard to control – especially as they have three to six generations per year, even in the Atlantic provinces. The 1/4-inch-long caterpillars, when agitated, squirm and usually fall off the plant. Row covers, Bt and Spinosad products can be used. Thresholds are 50% of the plants infested with five or more larvae each before cupping; 10% with 1 or more live larvae at the cupping stage. For cauliflower and broccoli, use the same thresholds but instead of the cupping stage use the stage when the head is just forming. In Hutton’s experience, these worms don’t get into the head as much as the other worms; more often they’re on the frame of the plant.
Aphid pressure is related to excess nitrogen. Aphids prefer mustards and collards, so these can serve as trap crops. Interplanting with a living mulch of clovers or even grasses can decrease aphids populations, because they provide habitat for many aphid parasites and predators. The intercrop will have to be mowed and possibly watered if it competes with the crop. Neem, soaps or pyrethrum (Pyganic) can be sprayed, possibly as spot treatments; when aphids find a host plant that they like, they stay there.
Thrips are more problematic on storage or processing cabbage than on the fresh market crop. They abrade the foliage with their rasping mouthparts, and warty, corky spots form as the foliage starts to heal. Sometimes the damage isn’t apparent until you peel the cabbage. Resistant or tolerant cultivars don’t have this wound response. Spraying usually won’t help because the thrips are within the plants. When a nearby field of rye, wheat or hay is cut, thrips will fly into nearby cabbages, so keep such crops far from cabbages.
Club Root, a devastating fungal disease that can be in the soil or on the seed, causes club-shaped roots. A lot of cabbage ground is infected with the disease. Growers can live with it if they need to through irrigation; managing the pH at 7.2 or higher; and growing heading types of brassicas rather than root crops (radish, turnip, rutabaga – all the roots will be misshapen). Practice good sanitation, said Hutton; the infected field should be the last field you work in that day or week, and then you should power wash your tractor and equipment and wash your boots and clothes. Eliminating club root takes at least a seven-year rotation, which includes keeping all brassica weeds out of that field.
Black leg (Phoma lingam), also soil- and seedborne, doesn’t occur much in Maine. The first signs usually occur on leaves, as small, yellow, circular spots that dry and fall out. Later black leg appears as black lesions on the stem, especially at the base. Good rotations and plowing brassica residue deeply into the soil reduce the occurrence, since spores in splashing rainwater can otherwise infect new crops. Use clean, hot water-treated, disease-free seed.
Black rot (Xanthomonas campestris) may occur in soils and on seeds. High humidity and rainy weather favor it because of guttation – that is, drops of water exuded at night from leaf veins around the margins of the leaves are pulled back into the leaf during the day, and they can bring pathogens with them. This is why black rot symptoms start at the tip of the leaf, as a characteristic V-pattern. Crop rotation, sanitation and resistant varieties can minimize the disease. Some literature suggests using compost tea, which seems to work on sporulating lesions to reduce the amount of inoculum in the field and slow the spread of the disease.
Fusarium yellows is a warm-weather disease, so it’s not a big problem in Maine. When it does occur, plants look fine until a hot, dry spell, and then they collapse because the disease attacks vascular tissues. Plants can be stunted and yellow. Symptoms often occur only on one side of the plant. Many cultivars are fusarium resistant.
Alternaria, a foliage disease favored by cool, wet conditions, causes the characteristic oystershell pattern seen with alternaria in other crops. The disease can be seedborne, so sow hot water-treated seed. Long rotations also help. Alternaria is often a secondary pathogen and typically doesn’t affect broccoli and cauliflower heads but will impact brussels sprouts, cabbage, kale and collards, making the leaves unmarketable. It can be a big problem in common cold storage, where the disease will “keep chugging along” and turn heads to mush, said Hutton.
Downy mildew occurs on broccoli more than on other crops, especially during cool, wet weather. It appears as a bluish haze on undersides of the foliage and attacks at all stages of plant growth. Sanitation, good water drainage in the field and good air circulation will reduce its impact. Many broccoli cultivars have some tolerance to downy mildew.
Bacterial soft rot results from a host of different bacteria that attack broccoli crowns, predominantly, and can do devastating damage. Some cultivars are tolerant, especially those with tight, dome-shaped heads that shed water – such as ‘Arcadia’ and ‘Marathon.’ During harvest, cut stems at an angle so that water rolls off; this reduces the spread of this disease.
Buttoning refers to premature formation of heads, which are then small. Broccoli is especially sensitive to the disorder. Anything that slows growth can lead to buttoning: insufficient fertility or water, excess heat or water, temperatures below 50 degrees for a couple of days, transplants that are so old that they aren’t actively growing when set in the field. Providing sufficient water (1 inch per week) and using row covers can help. Some growers said they had this problem with ‘Marathon.’ Hutton said that ‘Marathon’ is usually pretty reliable, but growers might want to try ‘Arcadia’ or ‘Gypsy.’
Riceyness and bract formation within heads of cauliflower is a stress response to heat and/or insufficient moisture. Heads are uneven and velvety, and flower structures emerge through them. Some varieties are more tolerant than others.
Brownbead refers to broccoli heads that are small, stop growing and turn brown. It can be a disease (soft rot) but is usually due to excess heat. Keep plants growing steadily.
Hollow stem without black corky areas usually occurs when excess N causes rapid growth. The hollow stems reduce marketable yield and can make the crop hard to sell. Growers can remove the stalks and just sell crowns. With broccoli, tighter plant spacing often decreases the incidence.
Tipburn – browned leaf edges – results from an imbalance of Ca, Mg, Mn and K in the soil, as well as excess N, too-rapid growth, high temperatures and water stress. The damage is usually well inside the head and isn’t apparent until the head is cut open. Balanced fertility eliminates the problem, and some cultivars of storage cabbage, such as ‘Storage No. 4,’ are tolerant.
Harvest and Storage
Cabbage – When stored around 32 degrees and with 90 to 100% relative humidity, storage cultivars will last up to about eight months. Remove all but a couple of wrapper leaves from the head when it goes into storage, and handle the heads somewhat gently so that they don’t bruise and rot. Controlled atmosphere storage, used in upstate New York, prolongs the storage life and quality of cabbage. Ethylene gives cabbage an off-taste and speeds its degradation, so don’t store it with apples, tomatoes, melons or other crops that produce this gas. It can be stored with potatoes and onions. The use of storage cabbage has gone way down with globalization of the food supply, said Hutton, but this is what people used to eat through the winter.
Cauliflower can be stored for two to six weeks at 32 degrees and with a humidity greater than 95%. Harvest plants when they’re a little immature, since heads open a little in storage. Cool them right after harvest and wrap them (e.g., in plastic bags) to increase storage life. Store them in one layer to prevent bruising.
Broccoli, the most perishable of the brassicas, lasts three to four weeks under the best conditions. It should be iced or put in a cooler within an hour of harvest. In The County, it’s cut and iced right in the field. Blanching broccoli in 116-degree water for 10 minutes or 122-degree water for two minutes after it has been brought in from the field and just before storage will prolong storage.
Brussels sprouts last for three to six weeks at 32 degrees and 95% humidity, or longer at 28 degrees and high humidity; the latter causes some freezing, so the crop needs time to thaw when it comes out of storage. Harvest fall cabbage and broccoli later in the day, after the frost has gone out of the crop; if harvested while frozen, it will break down.
Hutton listed the following favorite varieties among the staff at Highmoor Farm:
Early cabbage – ‘Spring Dynasty’ and ‘Dynamo’
Midseason cabbage – ‘Super Elite’ from Reed Seeds in New York. “I think that’s one of the best tasting cabbages out there,” said Hutton.
‘Lynx’ is a good, large, fresh-market cabbage or small, processing cabbage.
Late season cabbage – ‘Storage No. 4’ for storage, ‘Super Red 80’ for fresh market
Yellow cauliflower – ‘Cheddar.’ “The flavor’s incredible,” said Hutton. “It’s got the cauliflower flavor, but it’s got a little sweetness to it, and it keeps its color pretty well when you cook them. Everyone I’ve talked to who’s tried it, liked it.”
White cauliflower – ‘Brilliance,’ ‘Amazing’ (a persistent white; it doesn’t need to be blanched or tied up but is self-blanching, like most new varieties)
Purple cauliflower – ‘Graffiti,’ ‘Violet Queen’ (which is more of a broccoli)
Green cauliflower – ‘Aloe Vera’
For all cauliflower, Hutton said to plan for a September-October harvest; before that, a lot of the colored ones lack color or quality.
Hybrid broccoli – ‘Marathon,’ ‘Arcadia,’ ‘Gypsy’
Open-pollinated (OP) broccoli – ‘Green Magic,’ ‘Green Goliath’
Hutton said not to use close spacing on the OP varieties, since they tend to be flat dome types. For side shoots, he suggested the OPs and ‘Marathon’ and ‘Gypsy.’ An heirloom called ‘Chico’ is “all side shoots,” said one grower. Cutting the initial head before it reaches full size can stimulate side shoot production. Asked how to maximize yield with main and side shoots, Hutton said that succession plantings will usually yield more than keeping older plants going. He said the same is true with salad mixes. “Most people are finding now it’s more advantageous to have multiple beds, rather than try to get a second cut off the lettuce in salad mixes.”
Jason Kafka starts all his brassicas in a 26- x 48-foot greenhouse. He prefers to spend money on potting mix (4 tons per year, from Living Acres) and greenhouse space and get proper spacings in the field. He starts plants in cell trays (98s and 72s), filling the greenhouse four or five times a season as various vegetables are started and move out.
All his brassicas are planted on raised beds with black plastic and a single drip line down each bed. (The new, biodegradable BioTelo mulch, which Kafka trialed in a small area, “tickles my fancy,” even at twice the cost of nonbiodegradable plastic mulch, because it eliminates the cleanup and disposal costs. “It worked superbly.” This mulch is not yet OMRI-approved for organic production.)
Kafka trialed Queen Gil drip line last year and won’t use it again; “T-Tape is the drip tape of choice in my book. If you’re going to use drip line,” he continued, “go the extra cost and get the ones with the valve, so you can isolate beds.” The Rainflow catalog (https://rainflowagrotech.com/prod_cat.htm) helps growers determine the irrigation setup that will work on their soil types, slopes, etc. Hutton said that one advantage to drip irrigation is that you can be in the field working while it’s being irrigated.
Kafka removes and disposes of drip tape each year, to minimize diseases and because it usually leaks by the end of a season. (One year, fox kits suckled on his tape.) Laying drip tape and plastic mulch on half an acre of beds, using tractor-pulled implements, takes about 15 minutes. On a smaller scale, growers can put rolls on Garden Way carts, with a pipe through the roll, grab one end and “go for a walk.” At the end of the run, knot the tape.
On his bigger fields, Kafka uses low-flow drip tape, because the rows can be 600 feet long.
When crops aren’t grown on plastic, one grower suggested using microsprinklers instead of drip tape to avoid moving the tape when you weed. Kafka got around the weeding problem in crops such as carrots by bending a tube that enabled him to set the drip line about 4 inches under the soil. This 3-point hitch mounted tape dispenser feeds drip tape from the roll on top, down through a curved guide (a bent piece of pipe) into a shallow furrow cut by a knife that is mounted ahead of the tube. Once the tape is in the soil, the furrow is closed by two wings that push the two ridges of displaced soil made by the knife over the driptape. “The wind didn’t blow it, the critters never saw it,” he said.
For soil fertility, Kafka tills in a winterkilled cover crop of oats and compost or a 50:50 mix of chicken and cow manure. He plants about 1 1/2 acres of onions and follows this with cabbages and then a cover crop. “My goal is to have at least half the ground recharging” with a green manure or cover crop, depending on need, weather, etc., he said. A manifold in his pump house enables him to run fish fertilizer with his irrigation water, but he’s never needed to.
Transplanting and Growing
Kafka sets two rows of broccoli per bed, 18 inches apart within rows, with a water wheel planter – which punches a hole and fills it with water and Neptune’s Harvest fish fertilizer (about 1 gallon per 100-gallon tank of water). Workers sit behind this setting seedlings into the wet holes. He planted eight sequences of broccoli last year, seven of them ‘Arcadia.’ They were started 10 days to two weeks apart in the greenhouse.
His big planting is 1 1/2 acres of storage cabbage, mainly ‘Storage No. 4’ and ‘Ruby Perfection,’ which is “absolutely gorgeous.” Whole Foods takes several cases each week.
For pest control, “I will do one spray of Entrust in the season when I feel like the threshold has been hit, but insects haven’t been an issue with any of our brassica production.”
Kafka’s crew harvests into bulk crates, and he has bins on the front and back of his tractor. “We fill up two bins, the tractor boogies for the barn, drops them off, goes back for more.”
In his storage shed, he uses a stacker to stack bins three-high. He can fit 27 bins of 15 bushels each in each of the two storage rooms in his 1870 barn. “I’m starting to feel the pressure that I should build another storage room,” said Kafka. The 14- x 14-foot rooms have 10-foot ceilings and are insulated to R40 with 2 x 6 stud frames and fiberglass insulation, and 3-inch foam on the inside. He hopes to add a liner to protect the foam.
One room is refrigerated and, kept in the mid-30s, serves as a walk-in cooler in the summer.
“Humidity, particularly with the brassicas, is a non-issue for us. When the cabbages go in there, it’s in the upper 90s all the time. I’ve never had to do anything. One issue was keeping them cool enough. Cabbages like 32 degrees, and the cabbages were making so much heat [of respiration] that I had to keep the rolling doors and curtain open and blow cold air in through a lot of the winter just to keep them cool.”
His bigger cabbages go for processing and bring half as much per pound as storage cabbages that aren’t “pumpkin sized.” Storage cabbage is harvested in the “nasty cold,” when workers have to wear gloves, before it goes into storage. His crew had harvested about 24,000 pounds of those cabbages last fall.
Cabbages “want to grow in this environment, and they keep well as long as we can keep them cold enough,” said Kafka. He’s “totally enamored” with ‘Storage No. 4.’ “It’s like a cinder block, as far as its weight; it’s so dense.”
He pinches brussels sprouts about five weeks before harvest and later sells the crop as “sticks,” right on the stem. “It’s a novel way; the customer can see the traditional way they were sold.” Jan Goranson said she gets $3 to $4 per stalk, depending on the length.
Kafka keeps pushing kohlrabi, including ‘Kohlribi,’ ‘Vienna’ and ‘Gigante,’ which he sells at the Common Ground Country Fair.
One year, his average ‘Arcadia’ broccoli head was 10 inches across. “We were having a hard time packing a 20-pound box.” Whole Foods, the prime market, asked him to cut the stems about 5 inches longer than he had been, for easier banding and to distinguish the organic crop from Whole Foods’ nonorganic broccoli. “I like the idea: more weight per cut,” Kafka said, adding, “I’m real happy with Whole Foods. They’ve been very accommodating.”
Asked how early they plant broccoli, growers from Bowdoinham and from the coast said that they transplanted during the third week of April under row cover and had broccoli at the end of June. Kafka said he’s lucky to get it in by the end of May, “but we’re 100 miles in and at a higher elevation.” Hutton transplants in mid-May in Monmouth.
Jan Goranson questioned the return on early broccoli sold by the pound. “Are people selling it by the head in order to justify planting it?” One grower responded that it’s just a fall crop for her, because so many other crops are available in the spring. Another trialed ‘Gypsy’ and ‘Arcadia’ last spring and ‘Gypsy,’ ‘Arcadia’ and ‘Marathon’ for fall crops and sold it for $4 per pound all season. “Demand at the market was really good – maybe because nobody else had it [the early crop].” Kafka wholesaled side shoots to friends who have a farm stand nearby and who bagged the shoots. For his retail markets, customers wanted broccoli as soon as he had it. “It’s just one of those year-round vegetables that people want. It’s familiar to everybody.” One grower suggested that Goranson market her broccoli with a longer stem (for greater weight) – although Goranson thinks this would reduce side shoot production. Growers said they were getting $3 to $4 per pound.
“I’m really glad to hear this about spring broccoli,” said Hutton, “because, if you were to ask me, I wouldn’t grow it. Our [spring] broccoli from our research trials goes to the food bank, and we saturate them pretty quickly. We can’t even give it away.”
One grower said he had trouble with transplants rotting and dying. Kafka said that he sometimes has that trouble. To minimize it, he keeps fans going in his greenhouse all the time, and is careful not to overwater.
Asked about covering transplants started in summer to keep them cooler, Kafka said that his last plantings are in July for a fall crop, and he doesn’t have trouble with excess heat. He is in a cool part of Maine, but his transplants go through some hot days.
Nancy Chandler of Monmouth covers hers when she sets them out – to protect them from flea beetles. A grower in Sabattus has broccoli transplants through July in her greenhouse and doesn’t cover them.
Asked when to harvest broccoli, Kafka said there’s some leeway, and timing depends on how far along the crop is; what weather is predicted; and when an order is due.
Goranson picks cauliflower when it still has at least two leaves around the head so that she can grab it without touching the flower buds. “The minute you touch the head, you have ruined everything.” Heads become discolored through bruising. Most cauliflower varieties now are self-blanching, and their wrapper leaves protect them during harvest.
Regarding fall cleanup, Kafka bushogs his plantings, lifts the plastic and pulls it out, and goes over the plot with a rototiller operating at a slow roll, just to chop up the plants,
Another does the same, then fully tills the crop in and covers it. Hutton noted that working plant material into the ground deeply, by plowing instead of rototilling, will help reduce diseases that live on stalks.
After cleanup, growers spread cover crop seed with spinners. Kafka uses this $300 piece of equipment to broadcast peas and oats, then goes over the field with a rototiller quickly.
– Jean English