When to plant broccoli
Broccoli is a cool-season crop that shrugs off frost and light freezes, so it goes in well before the last frost. Type your town to see the dates for your weather station.
Broccoli in Columbus, OHZONE 6B
- Start seeds indoors
- Feb 7 to Mar 21
- Set plants outside
- Mar 21 to Apr 4
- Or sow seed outside
- Mar 21 to Apr 4
- Fall: transplant
- Aug 4 to Sep 8
- First harvest
- May 20 to Jun 9
Counted from the average last frost, Apr 18, and first frost, Oct 27, at Columbus Port Columbus Intl Airport, OH (NOAA 1991-2020).
The seed packet, in short
| Planting depth | 1/4 to 1/2 in |
|---|---|
| Spacing in the row | 12 to 24 in |
| Between rows | 18 to 36 in |
| Soil temperature | at least 40 °F, best 60 to 85 °F |
| Days to sprout | 3 to 10 days |
| Days to harvest | 60 to 80 days from transplant |
| Plants per person | 3 to 5 |
Broccoli plant planting dates by zone
Each row uses the typical frost dates of a zone: the middle value among towns of 10,000 people or more in it. In zone 6b, for example, the typical last frost is Apr 20, so the first step for broccoli, start seeds indoors, falls Feb 9 to Mar 23. Towns in one zone can differ by two weeks, so your own town's dates above are the better guide.
| Zone | Last frost | Start seeds indoors | Set plants outside | Or sow seed outside | Fall: transplant | First harvest |
|---|---|---|---|---|---|---|
| 4 | May 5 | Feb 24 to Apr 7 | Apr 7 to 21 | Apr 7 to 21 | Jul 13 to Aug 17 | Jun 6 to 26 |
| 5a | Apr 30 | Feb 19 to Apr 2 | Apr 2 to 16 | Apr 2 to 16 | Jul 17 to Aug 21 | Jun 1 to 21 |
| 5b | Apr 28 | Feb 17 to Mar 31 | Mar 31 to Apr 14 | Mar 31 to Apr 14 | Jul 24 to Aug 28 | May 30 to Jun 19 |
| 6a | Apr 24 | Feb 13 to Mar 27 | Mar 27 to Apr 10 | Mar 27 to Apr 10 | Jul 28 to Sep 1 | May 26 to Jun 15 |
| 6b | Apr 20 | Feb 9 to Mar 23 | Mar 23 to Apr 6 | Mar 23 to Apr 6 | Aug 1 to Sep 5 | May 22 to Jun 11 |
| 7a | Apr 14 | Feb 3 to Mar 17 | Mar 17 to 31 | Mar 17 to 31 | Aug 4 to Sep 8 | May 16 to Jun 5 |
| 7b | Apr 3 | Jan 23 to Mar 6 | Mar 6 to 20 | Mar 6 to 20 | Aug 10 to Sep 14 | May 5 to 25 |
| 8a | Mar 27 | Jan 16 to Feb 27 | Feb 27 to Mar 13 | Feb 27 to Mar 13 | Aug 15 to Sep 19 | Apr 28 to May 18 |
| 8b | Mar 16 | Jan 5 to Feb 16 | Feb 16 to Mar 2 | Feb 16 to Mar 2 | Aug 22 to Sep 26 | Apr 17 to May 7 |
| 9a | Mar 3 | Dec 23 to Feb 3 | Feb 3 to 17 | Feb 3 to 17 | Aug 31 to Oct 5 | Apr 4 to 24 |
| 9b | Jan 31 | Nov 22 to Jan 3 | Jan 3 to 17 | Jan 3 to 17 | Sep 16 to Oct 21 | Mar 4 to 24 |
Good to know about broccoli
- Broccoli tolerates light frost (down to about 28 F) but forms loose, bitter heads in hot weather, so time spring plantings to mature before summer heat.
- Use young, sturdy transplants; plants held too long in pots tend to form tiny early heads called buttons.
- For a fall crop, count back from your first fall frost using the variety's days to harvest plus about 10 days; heads can mature after light frosts.
How to plant broccoli
- Plant in full sun, at least 6 hours a day, in fertile, well-drained soil with plenty of organic matter.
- Broccoli likes slightly acid soil, about pH 6.0 to 6.5.
- Set out young, vigorous transplants, about 5 to 7 weeks old with 4 to 6 leaves.
- Water deeply so the soil is moist several inches down and keep it evenly moist, especially while heads form; mulch with 2 to 3 in. of straw or shredded leaves.
- Use a starter fertilizer at transplanting and side-dress with nitrogen about 3 to 4 weeks later, when plants are about half grown.
Types that change the timing
- Early varieties are ready about 50 to 55 days after transplanting; full-season varieties take about 60 to 75 days.
- Some varieties are bred to make lots of side shoots after the main head is cut, extending the harvest.
- Heat-tolerant, slow-bolting varieties can stretch the season into warmer weather.
Common mistakes
- Letting young plants go through a long cold spell, roughly 10 days below 50 F; this can make them form tiny heads or bolt.
- Letting plants run short of water or nutrients, which leads to early flowering and poor heads.
When broccoli is ready
- The central head is full size, firm and tight, often 4 to 6 inches across or more
Timing and spacing: compiled from these university extension guides, each figure checked against at least two of them:
- Colorado State University Extension: Vegetable Planting Guide (CMG GardenNotes #720)
- Virginia Cooperative Extension (Virginia Tech): Virginia's Home Garden Vegetable Planting Guide: Recommended Planting Dates and Amounts to Plant (426-331)
- University of Georgia Extension: Home Garden Planting Chart (B577)
- Kansas State University Research and Extension: Vegetable Garden Planting Guide (MF315)
- University of California Agriculture and Natural Resources, UC Master Gardener Program: Seed Germination Temperature and Timing
- Oregon State University Extension Service: When to start seeds indoors in central Oregon
- University of Maine Cooperative Extension: Maine Vegetable Gardening: Keep Your Garden Growing, Plant from Spring to Fall
- University of Illinois Extension: When should I start my seeds? (Good Growing)
- Cornell Cooperative Extension, Warren County: Fall Planting for the Vegetable Garden
- Cornell Cooperative Extension, Rockland County: Vegetable Planting Guide
- Utah State University Extension: Suggested Vegetable Planting Dates for the Wasatch Front
- University of Illinois Extension: Watch Your Garden Grow: Broccoli
- Utah State University Extension: Broccoli in the Garden
- yardandgarden.extension.iastate.edu
- hgic.clemson.edu
Frost dates: NOAA NCEI U.S. Climate Normals 1991-2020. General timing based on published university extension guidance and your local frost dates. Varieties and weather differ; your local extension office has the final word.