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- Start indoors
- Sow outdoors
- Plant out
- Plant
- Fall crop
- Today
Historical frost averages plus extension guidance, not a forecast. Check the forecast and soil temperature before planting.
Start broccoli seeds indoors 6–10 weeks before your last spring frost and plant them out 1–3 weeks before that frost date. For a fall crop, plant transplants out 10–14 weeks before your first fall frost. Broccoli likes cool weather and handles light frost.
- Frost tolerance
- Hardy: takes frost
- Soil temperature
- Sows at 45–85°F (min 40°F)
- Days to harvest
- 55–80 days from transplant
The rule we use
- Start seeds indoors: 6–10 weeks before the last spring frost
- Plant out: 1–3 weeks before the last spring frost
- Plant out for fall: 10–14 weeks before the first fall frost
Starting broccoli indoors
Sow seeds ¼ inch deep in seed-starting mix. They sprout quickly at room temperature, then grow best in a cool spot around 60–65°F under strong light. Plants are ready to go out when they're 5–7 weeks old with four or five true leaves.
Don't let them sit too long in small pots. Stressed, root-bound broccoli seedlings tend to "button": they form a tiny head early and never size up.
Planting out in spring
Broccoli can go out a few weeks before the last frost because it tolerates light frost. Harden plants off first, and cover them if a hard freeze in the mid-20s is forecast. Set them about 18 inches apart and keep the soil evenly moist.
The main risk with spring broccoli is heat. Once days get hot, heads loosen and flower quickly. Planting on time, rather than late, gives the heads a chance to form in cool weather.
Fall broccoli
Many gardeners find fall broccoli easier and better than spring. Plants grow through late summer and form heads as nights cool, and a light frost makes them sweeter. Plant transplants 10–14 weeks before your first fall frost; start seeds about 5 weeks before that.
After you cut the main head, leave the plant. Most varieties send up smaller side shoots for weeks.
Seeds and supplies for broccoli
- Broccoli seeds at True Leaf Market
- Park Seed for seeds and young plants.
- Seedling heat mats keep seed trays warm for fast, even sprouting.
- LED grow lights stop seedlings stretching toward a window.
- Frost cloth to cover plants if a late cold night is forecast.
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Questions about planting broccoli
Can broccoli go in before the last frost?
Yes. Hardened-off transplants can usually go out 1–3 weeks before your last frost date. Cover them if a hard freeze is forecast.
When should I plant broccoli for fall?
Set out transplants about 10–14 weeks before your first fall frost. Enter your ZIP above for exact dates.
Why did my broccoli make tiny heads?
Usually stress: plants held too long in small pots, cold snaps right after planting, or drought. Heat at heading time also makes heads loose and small.
Sources
- Vegetable Planting Calendar for Central Maryland (2026), University of Maryland Extension
- Vegetables for Spring and Fall Planting; Vegetables for Summer Planting, University of Maryland Extension Master Gardeners
- Extension Gardener Handbook, Ch. 16: Vegetable Gardening, NC State Extension
- Extension Gardener Handbook, Ch. 13: Propagation, NC State Extension
- Vegetable Planting Guide (CMG GardenNotes #720), Colorado State University Extension
- Can I start my seeds indoors yet?, Iowa State University Extension and Outreach
- Suggested Vegetable Planting Dates for Utah, Utah State University Extension
- Frost dates: NOAA NCEI U.S. Climate Normals 1991–2020 (doi:10.25921/4ek7-fk11)