Brussels Sprouts

Brassica oleracea (gemmifera group) (Brassicaceae or cabbage family)

Production

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Soil preparation

• Brussels sprouts should not follow after other members of the Brassica family. You can plant brussels sprouts after oats and peas, or after oats and hairy vetch. Hairy vetch, which survives over the winter in the northern United States, has the added benefit of reducing disease pressure.
• Average nutrient uptake is 236 lbs. of N, 29 lbs. of P and 235 lbs. of K.
• Apply compost and other amendments based on the results of a soil test.
• Spread lime as needed to increase both the pH and Ca levels. Dolomite lime will also increase Mg levels. Spread gypsum when calcium levels are low but pH is correct.
• A fertilizer company can add OMRI-listed potassium sulfate to compost if it doesn’t have enough K to meet the crop’s needs. If this isn’t possible, spread the correct amount of fertilizer and incorporate it before planting. Alternatively, you can side-dress it during cultivation. Divide the recommended rate of the soil test in half if side-dressing. 
• Test for boron and apply only as recommended by the soil test. A fertilizer company can add boron to compost to optimize boron distribution. If this isn't an option, distribute soluble boron through a water solution with a sprayer directly on the soil. If applied directly on the crop, don’t exceed more than 1 lb. of boron per acre to avoid leaf burn. Incorporate compost and plant brussels sprouts in either raised beds or on flat ground.

Common recommended fertilizer rates¹

Nitrogen	Phosphorus	Potassium	pH
120	0-160	0-200	6.2-6.5
1Rates are for New York and are from Cornell University’s Nutrient Guidelines for Commercial Vegetable Production (2019). Check the Cornell website for updated guidelines, or consult with local experts for recommended rates outside New York.

Varieties

• New Hampshire variety trial
• Brussels sprout varieties appear to change frequently. Look for disease resistance and uniformity when selecting a variety.

Greenhouse guidelines

• EZ Seeder seeder plate #16

Cell pack tray	Germination temp	Growth temp	Hardening off	Notes
72, 98 or 128	75°–90°	65°	Withhold water	Put plug trays on a wire mesh bench to encourage air pruning. Take plants outside 1 week before planting in field.

Transplant readiness indicators

• Harden plants off outside; plants that are lush don’t perform well in the field.
• Plants are ready when they pull easily from the cell. Plants should generally not be older than 5 weeks.

Transplanting in 5- or 6-foot raised beds

Rows	In-row spacing	Planting depth (inches)	Notes
2	18-24 inches	The plug is buried by soil	Use 18-inch sprocket or 18-inch water wheel; when not available, plant every other hole with a 12-inch wheel.

Transplanting tips

• Adjust mechanical transplanters so there is good contact between the plug or root ball and the soil.

Cultivation procedures

• Ensure plants are properly rooted before cultivation. Use sweeps (with torsions if possible) in combination with a finger weeder 7–10 days after transplanting, or as soon as possible without damaging the plants. Alternatively, use a tine weeder; but this works better when you use bare root transplants because tine weeders tend to uproot plugs.
• Hand hoe in between plants as necessary.
• Use a finger weeder in combination with side knives for a second pass when new weeds emerge. Move finger weeders away from the crop if they cause damage. Alternatively, if you want very slight hilling, use spring hoes in combination with side knives.
• If a third cultivation is possible before plants start closing in, use Lilliston rolling cultivators and hill aggressively without damaging the plants.

Insect and disease protection

• Control black rot (Xanthomonas) by purchasing clean seeds, keeping the greenhouse clean and exposing seed to hot water treatment. Some organic seed suppliers hot treat their seeds, so check with them before applying your own treatment, as double treatment can affect germination.
• Flea beetles
  • Cover the crop with floating row covers or insect netting after transplanting to avoid flea beetle damage. Keep covered until harvest. Alternatively, use a spinosyn-based product like Entrust. 
  • If possible, follow Extension bulletins that publish the timing of each generation of flea beetles, or place yellow sticky cards at plant height to monitor their presence. Check the cards at least twice a week.
  • Spray beneficial nematodes on heavily infected land to control flea beetle grubs and avoid future generations. Flea beetles tend to overwinter in nearby hedgerows and grass strips.
• Cabbage maggots: To reduce infestation of cabbage maggots on young seedlings, cover seedlings with floating row covers or insect netting as you would for flea beetles. Maggots appear in 3–4 generations in the Northeast, starting in early spring.
• Scout for the eggs of imported cabbage worms or diamondback moths on the underside of leaves. When the small worm population is more than 2 per plant, spray a Bacillus thuringiensis (Bt aizawai or Bt kurstaki) product, such as XenTari, or a spinosyn-based product, such as Entrust, every week until the population is under control. Alternate your spraying schedule by using Bt products along with a spinosyn-based product to avoid resistance buildup.
• To avoid Alternaria leaf spot, plant far away or upwind from earlier-planted cole crops, and avoid overhead irrigation during sprout formation. Regular applications of Bacillus amyloliquefaciens, available as Double Nickel, have shown the best controls in research. Bacillus subtilis, available as Serenade, and mineral oil like JMS Stylet-Oil has shown some control for a few growers. Regular sprays with giant knotweed extract, such as Regalia, appear to reduce Alternaria by activating the plant’s natural defenses against fungal and bacterial diseases.
• Swede midge has become a problem for many growers over the past few years. As it is an invasive species, it has no native enemies. Using row covers or exclusion netting in combination with rotating the crop more than ½ mile away from last year’s crop may provide effective protection.

Other cultural practices

• To induce greater yield and uniformity of sprouts, top the plants by removing or pinching the growing point in September, or when the lower sprouts are about ½–¾ inch.
• Slowly remove yellow leaves from lower parts of plants to keep sprouts healthy. 
• Irrigate frequently for optimum yield and plant health. Frequency depends on soil type, evaporation, precipitation and the particular needs of the crop. 

Double cropping and/or cover cropping

• Brussels sprouts stay in the field until late in the fall and aren’t always followed by a cover crop.
• Alternatively, you can overseed rye before the end of August. Take great care to avoid having seeds get caught in the plants

Additional resources

• Organic Production and IPM Guide for Cole Crops

Harvest

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Ready-to-harvest and quality indicators

• Sprouts are firm, solid and round without any sign of Alternaria on the center leaves of the sprouts.
• Some of the outer leaves can have some black spots, but clean these off during packing.
• Harvesting brussels sprouts after the first frost increases the sweet flavor of the sprouts.

Harvest and cleaning procedures

• Wash hands and sanitize pruning shears before harvesting.
• One person snaps the leaves off the stalks and removes the diseased sprouts at the bottom of the stalk. This person also snaps off the top of the stalk.
• A second person cuts the stalks with pruning shears and places them in a box.
• When the cutter catches up with the person snapping off the leaves, they can then count the stalks and pack them at 10–12 stalks per box.
• When sprouts are sold off the stalk: Remove all yellow and loose leaves, and trim the stem, leaving it straight and clean. Sort them to an average of 1.25 inches in diameter (no smaller than 1 inch and no bigger than 1.5 inches). Sprouts larger than 1.5 inches and smaller than 2.75 inches are sold as a different grade. 
• Do not wash brussels sprouts.
• Wash hands and rinse boots before entering the wash-and-pack shed, and cover up field clothes with a bib. If a long-sleeve shirt contains soil, remove this as well.
• Repack in a well-lit wash-and-pack shed into clean boxes for delivery.

Additional resources

• Wholesale grading and Packing Instructions
• Postharvest Factsheet Brussels Sprouts
• Production Guide for Storage of Organic Fruits and Vegetables

Packing and storage summary for brussels sprouts

Cleaning in the field	Remove leaves and diseased sprouts from the stalk.
Packing in the field	10–12 stalks in each 1 ¾-bushel box.
Packing for delivery	10–12 stalks in each 1 ¾-bushel box for both wholesale and CSA. When selling loose sprouts wholesale, pack 12 sprouts in 8 oz packages. See the International Federation for Produce Standards for the correct PLU code. Add the prefix 9 for organic crops.
Storage	At 32°–41°, 95–100% humidity. Brussels sprouts need good air circulation; don’t pack them in closed containers for long-term storage. Brussels sprouts are sensitive to ethylene exposure. Allow for good air exchange and don’t store with crops that release ethylene.

This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture through the Sustainable Agriculture Research and Education (SARE) program. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S. Government determination or policy.