Garden Vegetable - Broccoli

Estimated Planting Time for
Last Frost of Apr 1
First Frost of Nov 1

Botanical Information

Family: Cruciferae
Height: 18-24"
Type: Biennial
Spacing: 18" spacing
Growing Season: Spring, Fall
Approx Days to Harvest: 55

Starting

Earliest start outside: Feb 18
Soil: Ph 6.0-6.8
Opt Germ (soil) Temp: 55-75° F.
How Deep?: 1/2"
Time to Emergence: 5-17 days

Notes:

Succeeds in full sun in a well-drained heavy, fertile, preferably alkaline, soil. Tolerates a pH in the range 4.3 to 8.3. Succeeds in maritime gardens. Some forms are very cold-hardy, tolerating temperatures down to about -2°F. Broccoli is a close relative of the cauliflowers (C. oleracea botrytis) and is often grown for its edible young flowering stems which, by careful selection of varieties, can be available almost all year round from early summer right round to late spring. There are many named varieties and these can be classified into three main groups:

  • Calabrese, which matures in summer and autumn, is the least cold-hardy form. It produces green, or sometimes purple, flowering heads. Some forms will produce a number of side shoots once the main head has been harvested, though other forms seem unable to do this.
  • Romanesco matures in late summer and the autumn. It has numerous yellowish-green conical groups of buds arranged in spirals. Given a little protection from the cold, it is possible to produce a crop throughout the winter. Unlike the other types of broccoli, romanesco seems unable to produce side shoots once the main head has been harvested.
  • Sprouting broccoli is the most cold-hardy group. It does not form a central head like the other two groups but instead produces a mass of side shoots from early spring until early summer. The more you harvest these shoots, especially if you do so before the flowers open, then the more shoots the plant produces.

A good companion for celery and other aromatic plants since these seem to reduce insect predations.

Propagation: Seed - sow sprouting broccoli in a seedbed outdoors in March to May. Plant out in June. Do not let the seedlings get overcrowded or they will soon become leggy. If your seedlings do get leggy, it is possible to plant them deeper into the soil - the buried stems will soon form roots and the plant will be better supported. Romanesco and calabrese are often sown in situ in the spring.
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