Broccoli transpires quite a lot of water and for optimal growth the soil should be moist at all times. This isn't usually a problem because it grows in fairly cool weather.

Like most members of the cabbage family, Broccoli is a hungry plant and needs plenty of nutrients for good growth. It doesn't like acid soil.

For optimal growth the soil must be moist at all times. Fortunately it grows in fairly cool weather, so watering isn’t usually a problem.

In dry conditions or hot weather it is critical that the plants receive sufficient moisture. A lack of water may cause the plants to bolt.

1 gallon of water per plant should be enough, but use more if necessary.

Watering also depends on your local weather; don't water if it's raining, or water more frequently if it's dry. Just be sure to keep soil moist for the best crop. The best way to know how much moisture is in your soil is to feel 2" below the soil line. If it's dry, water.

If your soil is less than ideal, give your transplants a feed of compost tea or liquid kelp, 2 weeks after planting out. This will encourage rapid vegetative growth.

Competition from weeds can cause the plants to bolt, so keep them well weeded when small. A mulch will help here as well. When they are 12" tall you don't need to continue weeding as regularly.

A mulch will help to keep down weeds and keep the soil cool in warm weather. Broccoli loves seaweed mulch. If slugs and snails are a significant problem in your garden, don't mulch as it makes a perfect habitat for them.

You can avoid the most serious Cabbage pests by covering the young plants with row cover. This is a lot of work though, so don't do it unless they become a problem.

Two weeks before harvest you might give them another feed of compost tea to encourage the production of side shoots.