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Grow & Care - Broccoli

Fast Facts

Light Requirements Full Sun
Temperature Adaptations Hardy - Transplants may be set out as soon as soil dries out in the spring. Established plants will tolerate frost into the lower 20's. Plant late summer transplants July 1st to Aug 15th for fall harvest
Acidity (pH) Tolerance 6.8 to 6.0
Salinity (Ec) Tolerance 2.8
How Pollinated Insects
Growth Habits Biennial grown as an annual

Additional Information

Fertilizer Requirements

Broccoli plants tend to be heavy feeders. Apply 1 to 2 pounds of an all-purpose fertilizer (20-20-20) per 100 feet of row. Side dress 3 weeks later with ammonium sulphate at rate of 1/2 cup per 10 feet of row. Side dress broccoli again at time of first harvest to encourage side shoot development

Water Utilization

Broccoli should be supplied sufficient water to plants without creating waterlogged soil. Too much water is harmful.

Stress from inadequate water will decrease the quality and quantity of the broccoli harvest. Supplement sandy soils with organic matter to help hold moisture in the soil.

Plant Development and Care

Most often, broccoli is grown as a seedling for about 4 to 6 weeks then transplanted into the garden. Hardened-off transplants can go out 2 to 4 weeks before the average date of the last frost. Plants will get a faster start for an earlier harvest if the transplant is protected with a season-lengthening device such as wall-o-waters or floating row cover.

Established plants will tolerate frost into the lower 20's, but seeds do not germinate readily in cooler soils. Transplants should be started indoors and set out two to four weeks before date of last frost.

Broccoli develops more quickly when they are protected with season extenders. Broccoli planted and harvested earlier typically develop fewer problems with insect pests.

Broccoli grows to 48" and has a branching habit. The central stalk bears a cluster of green flower buds that may reach 6" in diameter. When the central cluster is removed, side branches produce smaller clusters.

As a cool season plant, Broccoli tends to bolt into flower in high heat, so it is best to plant early so it can mature in cool weather, or plant in midsummer to allow cool conditions at harvest. Assuming a mid-October average date of first frost, a fall crop may be transplanted between July 1st and August 15th for fall harvest. Adjust your harvest date according to seasonal frosts. Broccoli may be direct seeded July 5th to 10th for fall harvest.

Plants are very prone to looper and aphid invasions. Watch for these and treat the symptoms before they become serious infestations.

Germination Time (Days)

20 days at 50 F
10 days at 59 F
6 days at 68 F
5 days at 77 to 95 F

Seed Germination and Temperature Range

60 - 70 F

Common Fertilizer Deficiencies




Wash broccoli well; loopers (green caterpillars of a color that closely matches vegetable) may be hiding. A short soak in salt water will usually dislodge them.