Planting and Growing Broccoli

A cool-season crop, broccoli is best grown in the chillier weather of spring or fall. It takes a long period of time to mature. However, once you harvest the main head of a broccoli plant, it will frequently continue to produce smaller side shoots that can be enjoyed for months.

Broccoli should be planted in a site that receives full sun (6 to 8 hours of sunlight per day). Lack of sunlight could result in thin, leggy plants and subpar heads. Plant in a bed of moist, fertile soil that drains well. Ideally, the soil pH should be slightly acidic, between 6.0 and 7.0. Being a cool-season crop, depending on your climate, broccoli should be started in late winter or early spring for an early summer crop, or in mid to late summer for a fall crop. As a result of high temperatures, the development of the broccoli head (the harvestable part) will be impacted. The goal is to get broccoli to mature before and after high temperatures are expected to occur. While broccoli seeds are capable of germinating in soil temperatures as low as 40°F, warmer soil is preferred and will speed up development significantly.

To perform spring plantings, broccoli could be started indoors or outdoors a few weeks ahead of your last spring frost date. Begin seeds indoors 6 to 8 weeks before your last frost date. Sow seeds outdoors 2 to 3 weeks before your last frost date, or as soon as the soil can be worked in the spring. For fall plantings (best suited in warm climates), sow seeds outdoors 85 to 100 days before the first fall frost when the soil and ambient temperatures are high. If you’ll be starting seeds outdoors, sow seeds ½ inch deep and 3 inches apart. After seedlings reach a height of 2 to 3 inches, thin them so that the plants are 12 to 20 inches apart. If you started seeds indoors, plant transplants that are 4 to 6 weeks old (and have 4 or 5 leaves) outdoors 12 to 20 inches apart in holes slightly deeper than the depth of their container. Space rows of broccoli 3 feet apart. With closer spacing, it yields smaller main heads, but more secondary heads. Make sure to water well at the time of planting.

The broccoli plants work well in temperatures between 65°F and 70°F. Make sure to thin when young plants reach 2 to 3 inches tall; plants should be between 12 and 20 inches apart. With regular water, you can provide consistent soil moisture, especially in drought conditions. Be sure to water at least 1 to 1½ inches per week. Make sure to not get developing broccoli heads wet when watering because it could cause rotting. Suffocate weeds with mulch. When you mulch around plants, it will also help to keep the soil temperatures down. Always maintain an active feeding and watering schedule to maintain the growth of a second broccoli head after the first has been harvested.

To increase fertility before you plant, work in 2 to 4 inches of rich compost (humus) or a thin layer of manure in early spring. Fertilize broccoli three weeks after transplanting seedlings into the garden using low-nitrogen fertilizer, such as a 5-10-10 formula.

Harvest broccoli in the morning when the buds of the head are firm and tight, right before the heads flower. If you spot yellow petals, you must harvest immediately as the quality will rapidly decrease. Cut the heads of the plant and take at least 6 inches of stem. Create a slanted cut on the stalk so water can slide away. This is important because water can pool and rot the center of a flat-cut stalk, running the secondary heads. Most varieties have side shoots that will continue to develop after the main head is harvested. You may harvest one plant for many weeks—in some cases, from spring to fall if your summer isn’t too hot.