When to Plant Broccoli: Spring and Fall Dates by Frost and Zone

Broccoli goes into the spring garden as a transplant 1 to 3 weeks ahead of your median last frost. Plant as soon as the ground can be worked and reads at least 40°F (4°C) 4 inches (10 cm) down. A second crop, often the better one, goes out 70 to 100 days before the median first fall frost, so its heads form as the weather cools instead of as it heats up. In Texas, Georgia and along the Gulf, where autumn stays hot, that fall planting waits for the heat to break.

Both windows aim at the same target. Cole crops grow best between 60°F and 70°F (16–21°C). Hardened plants take light frost, but summer heat can stop heads forming, and weeks of chill on large plants make them bolt or set tiny "button" heads. Picking a planting date is really picking the weeks when the plant will reach heading size.

Broccoli planting dates by city

Count back from your own frost dates: each spring window opens 21 days and closes 7 days before the median last frost, and each fall window opens 100 days and closes 70 days before the median first frost.

Frost dates are medians from NOAA 1991–2020 climate normals for each city's main weather station; in half of years the last frost falls later than the date shown. Cells without exact dates, and the Dallas-Fort Worth fall window, follow state and county extension planting calendars.

The March windows for Boston, New York and Salt Lake City only apply once the bed has thawed and dried enough to dig; if it hasn't, wait for it. Seattle's maritime springs stay cool long after the last frost, so western Washington gardeners sow indoors in late March or early April and plant out in late May. Dallas–Fort Worth runs the other way, following the Texas rule of 4 to 6 weeks before the last frost: late January to early February on its March 8 median. Houston plants later than that rule would suggest: its best spring window runs from mid-January into late February, and early January plantings are marginal.

In the hot-autumn South, the fall count-back lands in late-summer heat, so the window moves later and closer to the first frost: September 1 to 20 in Dallas–Fort Worth, and mid-September to mid-October in Houston. Hardy, frost-tolerant plants have time to finish there, and in Houston they carry on through winter with cover on freezing nights. Where winter temperatures rarely dip below 32°F (0°C), transplants can go out any time from September to February.

Why fall broccoli often beats spring

Fall broccoli heads up in shortening, cooling days, which is why it often out-yields spring plantings in the Mid-Atlantic and is the preferred season in South Carolina.

A spring planting races the calendar. Its heads have to finish before summer heat arrives, heads that mature in July may bolt, and in South Carolina spring crops can form uneven heads. A fall planting runs the other way: the plants do their leafy growth in summer warmth and form heads as nights cool, and once hardened they keep growing after the first light frosts.

To fine-tune the fall date for your variety, take its days to maturity, add about 10 days, and count back from your median first frost. A 60-day variety goes out about 70 days ahead, and an 85-day fall type about 95 days ahead, near the early end of the window.

The hard part is raising seedlings in midsummer. Start fall transplants in a shaded spot, which is how Georgia gardeners raise them in August for setting out in September, and expect them to be ready in 5 to 6 weeks. Direct seeding avoids the nursery stage altogether and is common for fall in North Carolina; on Colorado's Front Range, fall broccoli is sown in place in early July. Seed sown in place takes about 20 days longer to reach harvest than a transplant, so sow about 3 weeks earlier than you would transplant.

Texas staggers its fall planting from July 15 in the state's coldest region to November 1 in its warmest, with the last good date 17 to 19 days after each opening date. In Pennsylvania, plantings staggered every 2 weeks from spring through August give a longer run of harvests.

How the timing shifts by region and zone

The frost rule fits Zones 5 to 7 best. Minnesota and the Pacific Northwest transplant later in spring, Texas sets spring plants out earlier, and in Georgia, Texas and along the Gulf, fall planting waits for the heat to break and runs closer to the first frost.

Windows from state and county extension planting calendars; your frost dates and soil set the exact week.

Zones 3 to 5. Minnesota gardens sow seed indoors in early to mid-April and set the plants out in May, around or just after the last frost rather than ahead of it. The upside is summer: in far northeastern Minnesota, where summers stay cool, broccoli can grow straight through the season.

Zones 6 and 7. This is where the frost rule fits best, and where the choice between a spring and fall crop is a real one. Maryland's 4-week lead and Colorado's 2 to 4 weeks sit at the bold end of the range; in a cold, late spring, keep to the 1-to-3-week window.

Zones 8 and 9. Fall is the main season, and small differences in latitude still count: north Georgia sets out fall broccoli about 2 weeks before the middle of the state, and south Georgia up to 2 weeks after. Spring is the riskier crop in the Southeast, because heads can come out uneven and a run of chilly days on large plants brings bolting. South Carolina's Piedmont sets spring plants out from March 20 to April 30, later than the frost arithmetic gives for Atlanta.

Zones 10 and 11 and the low desert. Broccoli is strictly a cool-season crop here, planted from late summer through winter. Around Phoenix, seed from mid-August through mid-December and set transplants out September 15 to December 15 and again in early January. Winter heads there take 90 to 100 days from transplants.

Pacific Northwest. Overwintering broccoli sown in early to mid-August is cut in November and December and again from January into May, which makes August the second planting date that counts in western Washington.

Starting seed and setting out transplants

Start seed indoors 5 to 7 weeks before your transplant date, which puts a spring sowing roughly 6 to 10 weeks before the last frost in most gardens.

1. Sow shallow and warm. Cover seed with 1/4 to 1/2 inch (6–13 mm) of mix and keep it near 75–80°F (24–27°C); seedlings appear in 3 to 10 days.
2. Grow seedlings for 5 to 7 weeks. In small plug cells, 3 to 4 weeks is enough. Set them out on schedule, because seedlings left in their containers grow rootbound and form buttons soon after planting.
3. Harden off. Give the plants several days outdoors, starting in shade, and cover them or bring them in on freezing nights so the hardening does not become a cold check.
4. Plant on a cloudy day or in the evening. Set each plant at the depth it grew in its pot, or slightly deeper. Weak sun lets the roots settle before the leaves face a full day of light.
5. Space for full-size heads. Allow 18 to 24 inches (45–60 cm) between plants and 24 to 36 inches (60–90 cm) between rows. In rich, intensively planted beds, plants can go about 12 inches (30 cm) apart, and western Washington gardens often use 12 to 18 inches (30–45 cm).
6. Feed and water evenly. Side-dress with nitrogen about 3 weeks after transplanting and again after you cut the main head, or at 3 and 6 weeks for a fall crop. The roots are shallow and fibrous, and drought or thin soil shows up later as small heads.

A plant spacing calculator works out how many plants a given bed will hold at your chosen spacing.

How to tell the soil is ready

Plant spring transplants once the soil reads at least 40°F (4°C) at 4 inches (10 cm) deep at 8 a.m. and is dry enough to work.

Take the reading first thing in the morning, when the soil is coldest, so a sunny afternoon does not flatter it. If you want a wider margin, wait until the soil holds 50°F (10°C) and the last hard frost of 28°F (−2°C) or colder has passed. Soil that still smears on the spade or sits frozen under the surface is not ready, whatever the thermometer says.

The site matters as much as the date. Broccoli needs full sun, at least 6 hours a day and ideally 8 to 10, and a rich soil, since it is a heavy feeder with a shallow root system. Where heavy ground stays wet into spring, a raised bed gives you a planting surface you can work on time.

Varieties that change the timing

Fast, heat-tolerant varieties suit spring, when heads must finish before summer, and slower varieties of 60 to 85 days suit fall, when heads can take their time in cool weather.

Days count from transplanting; add about 20 days for seed sown directly in the garden.

For spring, choose a variety of 50 to 60 days. Green Magic (57 days) and Gypsy (60) add heat tolerance for a late spring planting. Imperial has the best heat tolerance but takes 66 days, so it suits late-summer plantings for fall more than spring. For an overwintered crop, Marathon is the one to grow.

Broccoli raab runs on its own calendar: it is sown directly in the garden rather than set out as transplants, and around Sacramento it goes in from late September through February.

What happens if you plant too early or too late

Too early, cold makes broccoli button or bolt. Too late, spring heat stops the heads and a fall planting runs out of growing days.

Buttons are small heads that form soon after planting, and a buttoned plant will not go on to make a usable head. The triggers are prolonged cold below 50°F (10°C), extended chilling after very early planting, transplants held too long or roughed up before planting, drought and infertile soil. Temperatures below 45°F (7°C) can also stall heading, and larger plants that sit through 10 or more days in a row at 35–50°F (2–10°C) tend to bolt. If a planting buttons, pull it and replant with young transplants, or let the fall window take over.

Spring broccoli planted late meets summer heat before it heads. Hot spells with days of 86°F (30°C) or more and nights of 77°F (25°C) or more can stop heads forming, and heads that do form open into flower quickly. The fix is a fast, heat-tolerant variety or a switch to the fall planting. In fall, missing the window means plants are still leafy when hard cold arrives; the variety count-back is the cure.

If a late frost arrives

Hardened plants take light frosts without injury, and well-established plants tolerate harder frosts in spring and fall. Young transplants are the weak point. Cover new transplants whenever the forecast reaches 32°F (0°C) or below, using a heavier row cover in spring than the lightweight fabric used over summer plantings.

Harvest and what to expect

Most broccoli is ready 50 to 80 days after transplanting, a little longer in fall, and the first cut is followed by weeks of side shoots.

Cut the central head when it is 4 to 6 inches (10–15 cm) across and the buds are still tight, before any yellow flowers open. Texas gardens can let it reach 8 inches (20 cm). Leave the plant in place, keep feeding and watering, and side shoots will follow for several weeks.

Broccoli's two windows fall either side of the warm-season rush, so plan them alongside the rest of the beds with vegetable planting dates, cabbage planting dates and when to plant tomatoes. To keep both broccoli windows on one schedule, add them to Sow's garden calendar.