Growing Broccoli: A Complete Profile
By Growing Home Greens Team · July 18, 2026
Broccoli is a cool-season crop wearing a warm-season crop’s growing calendar in a lot of gardens. Start it too late in spring and heat pushes it to bolt into loose, bitter flower heads before it ever forms a proper crown.
Starting it early, and giving it a full square foot
Start seed indoors about 6 weeks before your last frost and transplant out roughly 2 weeks before that date. Broccoli tolerates a light frost far better than heat. Give each plant its own square foot; unlike denser greens, broccoli needs the room to bulk up into a full head. The main head comes first, and on most varieties, cutting it promptly encourages smaller side shoots to keep producing for weeks afterward. A summer-maturing head almost always bolts before it’s worth eating, which is why broccoli is usually grown as either an early-spring crop, started indoors in late winter, or a fall crop, started indoors in mid-summer for a harvest after the worst heat breaks.
Buttoning is a stress response from weeks earlier
A head that “buttons” (staying small and forming early instead of growing into a full crown) is almost always a stress response, usually from transplanting too late once temperatures are already climbing, or from a cold snap right after transplant. Loose, yellow-flowering heads mean the plant has already started to bolt; harvest what you can and move on, since the flavor only gets more bitter from there. General brassica pest pressure (flea beetles and cabbage worms) doesn’t care what’s planted nearby; a lightweight row cover over young transplants is the more reliable defense, physically keeping both off without needing to spray anything.
Dedicated space, not a gap-filler
Onion’s scent is reputed to confuse the cabbage moths that target broccoli and other brassicas. See the full companion guide for broccoli. Keep it away from tomatoes, since brassicas and tomatoes compete heavily and can stunt each other in a shared bed. At one plant per square foot, broccoli needs dedicated space in the Garden Designer. It’s not a crop you can tuck into gaps the way basil or lettuce can.
Companion planting guide for Broccoli · Find your planting dates
Typically viable in USDA zones 2-10. Not sure your zone? Look it up by ZIP code.
Mature height: 1.5-2 ft
Method: Start indoors: Start indoors from seed, then transplant outside. It needs a head start most zones can't give it by direct-sowing alone.
When to plant broccoli, by zone
Every zone broccoli grows in. Pick your zone in the header and it will be highlighted here. Each zone links to its full page.
| Zone | Start indoors | Sow or plant out | Harvest |
|---|---|---|---|
| 2a & 2b | Apr 8–Apr 15 | May 6–May 13 | Jul 10–Jul 17 |
| 3a & 3b | Apr 18–Apr 25 | May 16–May 23 | Jul 20–Jul 27 |
| 4a & 4b | Apr 3–Apr 10 | May 1–May 8 | Jul 5–Jul 12 |
| 5a & 5bSpring window | Mar 29–Apr 5 | Apr 26–May 3 | Jun 30–Jul 7 |
| Fall window | Jun 20–Jul 4 | Jul 18–Aug 1 | Sep 21–Oct 5 |
| 6a & 6bSpring window | Mar 14–Mar 21 | Apr 11–Apr 18 | Jun 15–Jun 22 |
| Fall window | Jun 30–Jul 14 | Jul 28–Aug 11 | Oct 1–Oct 15 |
| 7a & 7bSpring window | Feb 27–Mar 6 | Mar 27–Apr 3 | May 31–Jun 7 |
| Fall window | Jul 10–Jul 24 | Aug 7–Aug 21 | Oct 11–Oct 25 |
| 8a & 8bSpring window | Feb 11–Feb 18 | Mar 11–Mar 18 | May 15–May 22 |
| Fall window | Jul 26–Aug 9 | Aug 23–Sep 6 | Oct 27–Nov 10 |
| 9a & 9bSpring window | Jan 4–Jan 11 | Feb 1–Feb 8 | Apr 7–Apr 14 |
| Fall window | Aug 20–Sep 3 | Sep 17–Oct 1 | Nov 21–Dec 5 |
| 10a & 10bFall window | Aug–Dec | Sep–Jan | ~65 days after transplanting |
Harvest dates are about 65 days after the sow or plant-out date, not after starting seeds indoors.
Zone 2 sows before zone 3 here, which looks wrong and is not. USDA zones rank winter cold, not season length, and zone 2 is mostly interior Alaska, where hard winters come with warm summers. More on what a zone measures.
See exact start-indoors, direct-sow, and harvest dates for your zone →
How many Broccoli plants fit per square foot?
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1.5-2 ft.
Soil & water: pH 6.2-6.5. Needs well-drained soil. Amend with lime if soil pH falls below 6.2.
Good companions for broccoli
- Onion: Onion scent is reputed to confuse cabbage moths that target brassicas. The research behind this is real but garlic-specific (field trials intercropping garlic with cabbage reduced diamondback moth damage): onion hasn't been tested the same way, so treat the onion version as a reasonable extrapolation, not a directly measured result.
Full companion guide, including what to keep away from broccoli →
Varieties worth considering
- Packman: Utah State University Extension credits it with excellent production and eating quality for home gardens, the fastest of the school's three named picks at 50 days. (source)
- Green Comet: Also credited with excellent production and eating quality by Utah State, at 55 days, a middle option between Packman's speed and Premium Crop's size. (source)
- 'Waltham 29' (best for: fall crops, side shoots): Released in 1950 by the University of Massachusetts Waltham Field Station. The Vegetable Cultivar Descriptions for North America database, edited by Mark W. Farnham, credits it with uniform high yields, cold resistance, a dwarf, compact plant and big side shoots, and lists it as adapted to the East Coast and the Pacific Northwest. The cold resistance is what makes it a good pick for a crop that matures into fall. (source) Buy seeds: Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds
Why each variety is listed comes from the source shown next to it. We haven't grown these ourselves yet, so treat this as a research-backed starting point, not a personal endorsement. The buy links are separate from those sources: they go to seed suppliers that sell that exact variety, and we may earn a commission on some of them.
Where to buy broccoli seeds
Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds (each supplier's broccoli seeds)
The varieties we recommend above each have their own buy links, for the suppliers that sell that exact variety.
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See it growing
Search YouTube for "growing broccoli" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
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Growing Broccoli: A cool-season crop that bolts fast in heat. Timing matters more here than almost any other vegetable.
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