How to Grow Broccoli

General

One stalk of cooked broccoli gives you 75mg of vitamin C, 1300 IU of beta carotene, 3g of protein and 5g of dietary fibre with only 40 calories. No wonder they is one of the most popular vegetables you can eat today! The crown portion tastes great when cooked or steamed. You can eat the greens, too! Retain the stems for soups or soup stock.

Latin

Brassica oleraceae.
Brassicaceae Family.

Difficulty

Moderately difficult.

Season & Zone

Season: Cool season.
Exposure: Full-sun. Light shade will slow maturity.
Zone: Unknown zone.

Planting Seeds

Spring Planting-Summer Harvest: Start indoors Mar/Apr or direct-seed in late Apr/May. Harvest in 2-3 months.
Summer Planting-Fall Harvest: Start indoors or direct-seed late May-early June. Harvest in Sept/Oct.
Summer Planting-Spring Harvest (overwinter): Start indoors or direct seed June/July. Harvest next Apr/May.

Seeds will germinate at 45º F to 85º F. In the soil, seeds will germinate at temperatures as low as 40º F. It will take 4 to 7 days for the seedling to emerge.

Raising Transplants: Expensive hybrid seed will grow a strong plant from almost every seed, so are best raised as transplants. Put seeds about 1/2cm deep in sterile starting mix. Separate seedlings into individual 8cm (3") pots after 3 weeks. When plants have 4-8 true leaves (5-8 weeks old), harden them off and plant in the garden. Set plants deeper in the soil than they were in pots, right down to the healthiest big leaves.

To direct seed: Place 3-4 seeds in each spot you want a plant to grow. After a few weeks, thin to the strongest plant.

Keep soil warm (about 75º F), until germination. Then keep plants around 60º F. Provide direct sun so plants don't get leggy. When plants are 4 to 6 weeks old, transplant into garden 12 to 20 inches apart.

Preparing Soil

For good nutrition, mix complete organic fertilizer thoroughly into the oil below each transplant or before seeding. Stress causes tiny (button) heads, so do not let transplants grow too big for their pots, dry out, or be exposed to temperatures that are very cold or hot.

Broccolis are moderate to heavy feeders, best in rich, humus-y soil amended with composted manure. Add 4L (1 gallon) of complete organic fertilizer per 9sq m (100sq ft) of bed for background fertility. Lime beds in the fall, before planting, to bring the pH to 6-6.8.

Planting

Transplants should be set out by the time they have 6-8 true leaves. When plants are 20-25cm (8-10") tall, push soil around stems up to bottom of first big leaf to encourage large side-shoots. Broccoli does best in cool weather. Overwintering (sprouting) varieties should be side-dressed in February with a nitrogen fertilizer.

Use wide spacings if you want to harvest large central heads. Closer spacings will produce smaller central heads. But if you harvest secondary heads you will get a greater total yield from the closer spacings. Space 18-24" apart in rows 45cm-60cm (18-24") apart. Larger, older transplants are more likely to bolt when exposed to cool temperatures in the garden.

Broccoli can be direct-seeded as soon as you can work the soil. Will germinate at soil temps as low as 40 F. Plant seeds in clumps, ½ to ¾ inch deep, about 45cm (18") inches apart. Thin carefully, leaving the strongest plant. Direct seed in midsummer for fall crop, or start transplants in late May and transplant in late June or early July.

Use low nitrogen fertilizer at planting. Too much nitrogen fertilizer may cause hollow stems. Broccoli plants have shallow root systems. Avoid even shallow cultivation. Mulch to protect roots, reduce weed competition and conserve moisture. Use floating row covers to help protect from early insect infestations. To help reduce disease, do not plant broccoli or other cole crops in the same location more than once every three or four years.

Diseases & Pests

Slugs and snails - Slugs are attracted to beer, so place a little beer in a cup dug into the ground. Sprinkle broken eggshells around plants to deter slugs and snails.
Flea beetles - Use row covers to help protect plants from early damage. Put in place at planting and remove before temperatures get too hot in midsummer. Control weeds.
Cabbage root maggot - White maggots (larvae) attack all plants of the cabbage family. Larvae tunnel in and feed on roots of plants. Damage causes wilting early on, death of plants a little later on.
Cabbage aphids - A hard stream of water can be used to remove aphids from plants. Wash off with water occasionally as needed early in the day. Check for evidence of natural enemies such as gray-brown or bloated parasitized aphids and the presence of alligator-like larvae of lady beetles and lacewings.
Cabbageworms - Handpick and destroy. Row covers may be useful on small plantings to help protect plants from early damage. Put in place at planting and remove before temperatures get too hot in midsummer.

To help reduce disease, do not plant broccoli or other Cole crops in the same location more than once every three or four years.

Harvest

Cut the crown portion of the broccoli with 5 to 6 inches of stem, after it's fully developed, but before it begins to loosen and separate and the individual flowers start to develop into bright yellow blooms. Removing the central head stimulates regrowth to develop for later pickings. Cutting the head lower on the stem will encourage fewer, but larger side-shoots. The regrowth portion grows from the base of the lower leaves. You can usually continue to harvest broccoli for several weeks.