Harvest guide
When to Plant Broccoli (Spring and Fall Timing by Zone)
Set broccoli transplants out 2 to 4 weeks before your last spring frost, once soil reaches about 40 F. For a fall crop, plant 6 to 10 weeks before the first fall frost. Timing by zone, soil-temp cues, and the common mistakes.
Days to maturity
60–90days
Ready when
Tight green head before buds open to yellow
The short answer
For a spring crop, set broccoli transplants out 2 to 4 weeks before your last spring frost, once soil reaches about 40 F. For a fall crop, plant 6 to 10 weeks before your first fall frost, usually mid- to late summer. Broccoli is a cool-season crop, so aim for heads to mature in cool weather at either end.
Broccoli has two planting windows, not one. You can grow it as a spring crop that finishes before summer heat, or a fall crop that matures into the first cool nights. The trick is the same both times: get the heads to fill out while the weather is still cool. This guide covers when to plant by zone, the soil-temp cues, and the early-planting mistake that costs people a crop.
When to plant broccoli by climate and zone
The target is cool weather at harvest, so the planting date keys off your frost dates, not the calendar. For spring, University of Illinois Extension and Virginia Cooperative Extension both put hardened transplants out 2 to 4 weeks before the last spring frost. For fall, you count backward from the first fall frost instead.
Colder zones have a shorter spring window and an earlier fall planting. The dates below are starting points. Watch your own frost dates and soil temperature.
| Region / zone | Spring transplant | Fall transplant |
|---|---|---|
| Cold (zones 3–5) | 2–4 weeks before last frost (Apr–May) | Mid-July |
| Temperate (zones 6–7) | 2–4 weeks before last frost (Mar–Apr) | Late July – early Aug |
| Mild (zones 8–9) | Late winter (Feb–Mar) | Aug – early Sept |
University of Georgia Extension suggests starting fall seeds in late July and transplanting by the end of August in the South. Shift everything earlier as you go north and colder.
How to tell it is time to plant
Two signals tell you the ground is ready. Soil temperature and frost risk matter more than the date on the calendar.
Broccoli germinates once soil hits about 40 F and grows best around 60 to 70 F, per Ohio State and Virginia Cooperative Extension. Hardened transplants shrug off light frost down to roughly 28 F, so you can plant before the last frost is fully past.
Here is the quick read on timing a planting:
- Soil has warmed to at least 40 F (a cheap soil thermometer settles this).
- You are within 2 to 4 weeks of the last spring frost, or 6 to 10 weeks before the first fall frost.
- Transplants have been hardened off over about a week outdoors.
- The forecast shows cool weather, not a heat wave, in the coming weeks.
Pro tip
Start spring seeds indoors 4 to 6 weeks before the transplant date, per Iowa State Extension. That gives you a stocky 4 to 6 inch seedling ready to go out on schedule. Harden it off first: a week of increasing time outdoors so the move does not stall the plant. A stalled transplant heads up small.
Spring vs fall: pick the easier season for your climate
Both seasons work, but one is usually easier than the other where you live. The deciding factor is how fast your spring heats up.
In cold and temperate zones, fall is often the more reliable crop. The weather cools steadily into harvest, so heads fill out without the race against summer heat that a spring crop runs. Clemson Extension and Iowa State both treat fall broccoli as a strong option for this reason.
In mild zones (8–9), the fall and winter window is the main event. Summers are too hot for spring broccoli to head well, so most growers plant in late summer for a fall and winter harvest.
For the fall crop, set transplants out 6 to 10 weeks before your first fall frost. Broccoli needs roughly 50 to 85 days from transplant to a cuttable head, depending on variety and weather, so count back from frost and add a couple of weeks for slower fall growth. That timing is the same rhythm that drives when to plant lettuce, another cool-season crop you can slot into the same beds.
Common mistakes when timing broccoli
The biggest error is planting too early into cold soil. Cold, wet ground below 40 F stalls a transplant and can rot direct-sown seed before it sprouts. A stalled plant sits, sulks, and heads up small, if at all.
Common mistake
Three timing errors cost you heads. Planting into cold soil below 40 F stalls the transplant. Planting a spring crop too late runs the heads straight into summer heat, so they bolt and flower before they fill out. Planting a fall crop too late leaves no time to mature before a hard freeze. Count back from your frost date and check the soil temperature before you plant.
Heat is the other trap. Broccoli that matures in temperatures above the mid-70s tends to bolt, with the head loosening and the small green buds opening to yellow flowers early. That is why a spring crop has to go in early enough to finish before high summer, and why the fall crop is timed to head up as the weather cools. The same brassica timing logic applies to when to harvest cabbage, a close cousin in the bed.
Get the spacing right before you plant
Spacing decides head size, so set it before you put transplants in the ground. Broccoli wants room: crowd it and every head stays small.
Work out how many plants your bed holds before you buy starts. The guide to how far apart to plant broccoli walks the in-row and between-row numbers, and the plant spacing calculator counts how many fit your exact bed.
Try it — Plant Spacing Calculator
Full calculatorExtra to cover losses (10% is typical).
You can plant
32plants
- Per row
- 8
- Rows
- 4
- Buy (incl. spare)
- 36 plants
Your next step
Plant broccoli for cool weather at harvest. In spring, set transplants out 2 to 4 weeks before your last frost once soil hits 40 F. In fall, plant 6 to 10 weeks before your first frost, usually mid- to late summer. Check the soil temperature, count back from your frost date, and harden off your starts before they go in.
Ready to lay out the bed? Open the plant spacing calculator and set broccoli at its proper spacing so every plant has room to size up. Then read when to harvest broccoli for the cues that tell you a head is ready to cut.
Common questions
When should I plant broccoli?
For a spring crop, set hardened-off transplants out 2 to 4 weeks before your last spring frost, once soil warms to about 40 F. For a fall crop, plant 6 to 10 weeks before your first fall frost, usually mid- to late summer. Broccoli is a cool-season crop, so it heads up best in cool weather at both ends of the season.
Can you plant broccoli from seed directly in the garden?
You can, but most gardeners transplant for a more reliable head. Iowa State Extension notes broccoli is usually started indoors 4 to 6 weeks before the transplant date. Direct sowing works best for a fall crop in mild climates, since the soil is already warm enough to germinate seed in summer.
How late is too late to plant broccoli?
Count back from your first fall frost. Broccoli needs roughly 50 to 85 days from transplant to harvest, so set plants out at least that far ahead of frost, plus a couple of weeks for slower fall growth. In much of the US that means transplanting by late August. Broccoli tolerates light frost, so a few cold nights at the end are fine.
What temperature is too cold or too hot for broccoli?
Broccoli germinates at a soil temperature of about 40 F and grows best around 60 to 70 F, per Ohio State and Virginia Cooperative Extension. Hardened transplants tolerate light frost down to roughly 28 F. Sustained heat above the mid-70s makes plants bolt and the heads open early, which is why spring crops should mature before high summer.
When do I plant broccoli for a fall harvest?
Set fall transplants out 6 to 10 weeks before your average first fall frost. University of Georgia Extension suggests starting seeds in late July and transplanting by the end of August in the South. Cooler northern zones start a few weeks earlier so heads mature before a hard freeze.
Sources
Agronomic claims in this guide are checked against these primary sources.
- Broccoli — University of Illinois Extension
- Broccoli — Clemson Cooperative Extension Home & Garden Information Center
- Growing broccoli — University of Minnesota Extension
- Growing Broccoli in the Home Garden — Iowa State University Extension and Outreach
- Home Garden Broccoli — University of Georgia Extension
Keep reading
When to Harvest Broccoli (Signs It's Ready)
Broccoli is ready about 60 to 90 days after planting, when the central head is 4 to 7 inches across with tight, dark-green buds, before any open to yellow. Here are the cues, the cut, and the weeks of side shoots that follow.
Read →When to Plant Lettuce (Spring and Fall Timing by Zone)
Plant lettuce 2 to 4 weeks before your last spring frost, once the soil hits 40°F. It germinates best at 60 to 70°F and bolts in summer heat, so sow again 6 to 8 weeks before the first fall frost.
Read →When to Harvest Cabbage (Signs It's Ready)
Cabbage is ready about 70 to 100 days after transplanting, when the head feels firm and solid as you squeeze it and has reached full size for the variety. Cut it before it splits.
Read →When to Plant Zucchini (Frost + Soil Temp Timing)
Plant zucchini after your last spring frost, once the soil hits at least 60 F (ideally 65 to 70 F). Direct-sow seeds 1/2 to 1 inch deep, or set out transplants started 2 to 4 weeks earlier. Warm zones get a second fall crop.
Read →When to Plant Tomatoes (Frost + Soil Temp by Zone)
Set tomato transplants out 1 to 2 weeks after your last spring frost, once soil hits at least 60 F. Start seeds indoors 6 to 8 weeks before that frost date. Cold soil stalls them, so wait for warmth.
Read →When to Plant Swiss Chard (Spring and Fall Timing)
Plant swiss chard 2 to 4 weeks before your last spring frost, once the soil hits 40°F. Sow again 3 to 4 weeks before the first fall frost. Seeds go half an inch to an inch deep.
Read →