Standard Heading Broccoli Key Growing Information

A head of standard broccoli, growing in the field.

SCIENTIFIC NAME:

Brassica oleracea

CULTURE:

Broccoli prefers a well-drained, fertile soil that is high in organic matter with a pH of 6.0–7.5. A consistent supply of moisture throughout the growing season is important; irrigate regularly for best results. While more heat-tolerant varieties are now on the market, broccoli does not generally do well in hot weather. The best success is with spring and fall crops.

DAYS TO MATURITY:

From date of transplanting; add about 20 days if direct seeding.

EARLY SPRING CROP:

Use early and midseason varieties. Sow 2 seeds per cell in 72-cell plug flats, 3–4 seeds/in. in 20 row flats, or in outdoor beds ¼" deep. Seedlings should be ready to transplant in 3–4 weeks. If possible keep soil temperature 75–80°F (24–27°C) until germination, then reduce air temperature to about 60°F (16°C). Ensure good air circulation and light. Transplant outdoors 10–18" apart in rows 18–36" apart. Broccoli prefers cooler growing temperatures, between 55–75°F (13–24°C), optimum being 60–70°F (16–21°C), but will produce good crops under warmer, summer conditions.

FALL CROP:

Use midseason and storage varieties. Start seedlings as above in May and transplant to the garden in June–July. To ensure mature heads, seed the crop early in areas where heavy freezes occur early in fall.

WINTER CROP:

Successful broccoli crops can be grown where winters are mild (temperatures rarely below 32°F [0°C]). Transplants can be set out from September to February in these regions.

DIRECT SEEDING:

Sow 3 seeds per foot, ½" deep, rows 18–36" apart, thinning to one plant in each group.

AVG. DIRECT SEEDING RATE:

1,000 seeds/333' at 3 seeds per foot, 49,800 seeds (avg. 8.3 oz.)/acre spaced 7" apart in rows 18" apart.

INSECT PESTS:

Repel flea beetles and root maggots on young seedlings by covering with floating row covers from day of planting. Treat flea beetles with insecticides such as pyrethrin or azadirachtin if heavy pressure is observed. For cabbage worms and loopers, use Bacillus thuringiensis. Cutworm prevention: Cultivate soil 2–4 weeks before planting to work in cover crops and destroy weeds.

DISEASES:

Adhere strictly to a preventive program including: (1) long crop rotations with non-brassica crops, (2) clean starting mixes and outdoor seedbeds, and (3) strict sanitation practices. Johnny's Selected Seeds only sells seed lots of broccoli that have tested negative for black rot (Xanthomonas campestris pv. campestris) and black leg (Phoma lingam). NOTE: A disease-free test result means that in the sample tested, the pathogen targeted was not found. It does not guarantee a seed lot to be disease-free. However, no method of seed treatment can positively insure freedom from disease. We are glad to help with specific questions.

HARVEST:

Before flower buds open, cut center head. Hydrocool or ice as soon as possible. Harvest secondary side shoots regularly to encourage continued production.

STORAGE:

Store at 32°F (0°C), 95–98% relative humidity, with good air circulation for 10–14 days.

SIZED SEEDS:

"Sized" seeds have been sorted so they are roughly the same size. This consistency allows for more accurate spacing with mechanical seeders and more even germination. Broccoli seeds are sized, except when noted in the product description.

TYPICAL PLANT POPULATION:

43,560 plants/acre (1 sq.ft./plant) spaced 8" apart in rows 18" apart.

TRANSPLANTS:

Avg. 850 plants/1,000 seeds.

SEEDS/LB.:

52,900–142,100 (avg. 104,100).

PACKET:

100 seeds, sows 50'.