How to grow Broccoli

Brassica oleracea (Italica Group)

Apply fertilizer to developing seedlings beginning when the first true leaves appear. Fertilize three weeks after transplanting. Use starter fertilizer for transplants and side-dress with nitrogen fertilizer when the plants are half grown 6.

Water regularly – broccoli requires large amounts of water. Both dry soil and waterlogged soil reduces yields. Some varieties of broccoli are heat tolerant, but all need consistent moisture. Do not get developing heads wet when watering 4.

Mulch well to control weeds and to regulate the soil temperature.

The roots are very shallow, do not cultivate around your planting – suffocated weeds with mulch instead 4.

Monitor for insect and disease problems.

Many broccoli varieties are prone to bolting in hot weather.

Handle transplants carefully, control cutworms and avoid low temperatures to avoid damage to the terminal growing tip. Most Broccoli varieties grow best when temperatures are not too hot or too cold. Purple sprouting broccoli is a hardy variety which is planted in the spring or summer for harvest the following spring.

Ideal brassica crop rotation is to only grow them once in every 3 years in the same plot. Good preceding crops are onions and potatoes, or various (non-cruciferous) green manures, such as clover or ryegrass 5.

Growing Broccoli from seed

Sow indoors 2-3 weeks before your last spring frost, for spring planting. For autumn planting, sow 85-100 days before your first expected frost 4.

Try to aim for a seed spacing of at least 5.85 inches (15.0 cm) and sow at a depth of around 0.51 inches (1.3 cm). Soil temperature should be kept higher than 10°C / 50°F to ensure good germination.

By our calculations*, you should look at sowing Broccoli about 45 days before your last frost date .

Transplanting Broccoli

Can be station-sown direct, but for best results should be raised in seed bed and transplanted when big enough to handle. Transplant broccoli when seedlings have second set of leaves.

Ensure that temperatures are mild (minimum night temperatures should be around 7°C / 45°F) and all chance of frost has passed before planting out, as Broccoli is a half hardy plant.

By our calculations*, you should look at planting out Broccoli about 21 days before your last frost date.

Harvesting Broccoli

Harvest broccoli when the flower shoots are well developed, but before the flowers themselves have opened.

Seed Saving Broccoli

Broccoli will cross-pollinate with all other Brassica oleracea, so isolate when going to seed. Do not harvest heads on plants you intend to save for seed. 2 Some early broccoli will flower in the first year. Remove whole plant and hang to dry. 3
Seed viability is three to five years.

How long does Broccoli take to grow?

These estimates for how long Broccoli takes to sprout, grow and harvest are from real observations from real gardeners, right around the world.

Days to Germination How long does it take Broccoli to germinate?
6 days

Average 6 days | Min 2 days | Max 18 days (712)

Days to Transplant How long until I can plant out Broccoli?
+ 35 days

Average 35 days | Min 1 days | Max 88 days (273)

Days to Maturity How long until Broccoli is ready for harvest / bloom?
+ 100 days

Average 100 days | Min 4 days | Max 229 days (524)

Total Growing Days How long does it take to grow Broccoli?
= 141 days

When should I plant Broccoli?

Our when to plant Broccoli estimates are relative to your last frost date.

When to sow The number of days to sow Broccoli before or after your last frost date.
45 days before Last Frost Date
When to plant out The number of days to plant out Broccoli before or after your last frost date.
21 days before Last Frost Date

Other names for Broccoli

Calabrese, Purple sprouting broccoli, White sprouting broccoli

Brassica oleracea, Brassica oleracea var. italica

Misspellings: Brocoli, Brocolli, Broccolli, Brassica oleracea var. italica, Broccoli, Brassica olderacea italica, Brokoli


1 Cass County Extension

2 Seed Savers

3 “The New Seed-starters Handbook; Published 1988”

4 Almanac

5 Nickerson Zwaan Brassica growing guide

6 University of Illinois Extension

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