Brussels sprouts are a cool weather, full sun crop cultivated from seed or via greenhouse transplant. Sprouts grow sideways at the base of each leaf of a central stalk, maturing from bottom to top.
Ideal growing temperature is between 58 to 60°F in moist, well drained, medium to heavy soil. Plants require consistent watering and plentiful moisture to thrive. Light to heavy frost is well tolerated and will produce the best flavor—provided temperatures don’t go below freezing. Quality sprouts are bright green and firm with no yellowing or discoloration.
Plants may be harvested about 100 days after seeding. Sprouts are harvested more frequently in the early warmer part of the season and less often as weather cools. Sprouts are picked by hand and placed in baskets, then packaged and refrigerated to avoid rapid deterioration.
Pests & Diseases
Common pests include cabbage aphids and worms, cabbage root maggots, flea beetles, cutworms, loopers, slugs, harlequin bugs, diamond back moths, thrips, web worms, and nematodes.
Diseases of concern include downy mildew, clubroot, and internal browning. Injuries from rough handling can bruise sprouts and encourage decay.
Storage & Packaging
Brussels sprouts can be stored at 32°F for 3 to 5 weeks, at 41°F for 10 to 18 days, and 50°F for a week or less. Postharvest sprouts are usually cooled (air or hydro) with optimum humidity of 95% or greater. Lower humidity can result in wilted leaves due to moisture loss.
Sprouts have high respiration rates and sensitivity to ethylene, which may result in yellow, detached leaves. Sprouts will freeze at just below 31°F resulting in dark, translucent patches. Severely frozen buds are entirely dark and translucent, and become soft when thawed.
References: Cornell University, North Carolina State University Cooperative Extension, UC Davis Postharvest Technology Center, University of Florida/IFAS Extension.
GRADES & GOOD ARRIVAL
Brussels sprouts come in U.S. No. 1 and No. 2 grades.
Generally speaking, the percentage of defects shown on a timely government inspection certificate should not exceed the percentage of allowable defects, provided: (1) transportation conditions were normal; (2) the USDA or CFIA inspection was timely; and (3) the entire lot was inspected.
|U.S. Grade Standards||Days Since Shipment||% of Defects Allowed||Optimum Transit Temp. (F)|
Canadian good arrival guidelines (unless otherwise noted) are broken down into five parts as follows: maximum percentage of defects, maximum percentage of permanent defects, maximum percentage for any single permanent defect, maximum percentage for any single condition defect, and maximum for decay. Canadian destination guidelines are 15-10-5-10-4.
References: DRC, PACA, USDA.
• Size- unless otherwise specified, the diameter shall be not less than 1 inch, and length not more than 2.75 inches
• Discolored leaves- score when 2 or more portions of leaves are affected by yellow, brown, or black discoloration that materially detracts from appearance
• Insects- slight aphid infestation within the compact portion of the head is scored as a defect when there are more than 2 aphids present; when aphids affect the outer leaves, they are considered a defect if more than 4 are present.
Source: Tom Yawman, International Produce Training, www.ipt.us.com.