How to Grow Broccoli
Brassica oleracea var. italica
Broccoli is a versatile cool-season brassica prized for its tender green florets and robust flavor. Gardeners cultivate it to enjoy fresh harvests in spring or fall, benefiting from its ability to tolerate light frosts while providing essential nutrients.
📷 Wikipedia: BroccoliStarting Broccoli: indoors or direct sow?
🏠 Start indoors 6 weeks before your last spring frost, then move the seedlings outside.
Start seeds indoors six weeks before the last frost date, then transplant seedlings outdoors once they are hardy and soil temperatures have cooled sufficiently for brassicas.
Soil, care & harvest
Prepare your garden bed with rich, loose soil adjusted to a pH between 6.0 and 7.0 for optimal growth. As a cool-season crop, sow seeds indoors starting six weeks before the last spring frost or direct-sow outdoors two to six weeks prior. Press seeds gently into the soil at a depth of about one-quarter inch, expecting germination within five to ten days.
Space plants eighteen to twenty-four inches apart to ensure proper air circulation and head formation. Water consistently to provide one to one-and-a-half inches per week, keeping the soil evenly moist but not waterlogged. Apply a layer of mulch around the base to retain moisture and suppress weeds, feeding regularly with balanced fertilizer during active growth.
Watch for common brassica pests like cabbage loopers and aphids, which can be managed by encouraging beneficial insects or applying insecticidal soap. Prevent fungal diseases such as clubroot by ensuring good drainage and avoiding overhead watering. Harvest the main head when it is firm and tight, typically sixty to one hundred days after sowing, cutting the stalk just above the base.
When to Plant Broccoli
Planting windows vary by USDA hardiness zone. Look up yours by ZIP code.
| Zone | Start Indoors | Direct Sow | Harvest |
|---|---|---|---|
| Zone 1 | April – May | June – July | December – September |
| Zone 2 | April – May | May – July | December – September |
| Zone 3 | March – April | May – June | December – October |
| Zone 4 | March – April | April – June | December – October |
| Zone 5 | February – March | April – May | December – November |
| Zone 6 | February – March | April – May | November |
| Zone 7 | February – March | March – May | November |
| Zone 8 | January – February | March – April | October – December |
| Zone 9 | January | February – March | September – December |
| Zone 10 | January | January – March | September – December |
| Zone 11 | January | January – February | August – December |
| Zone 12 | January | January – February | August – December |
| Zone 13 | January | January – February | August – December |
