When to plant broccoli

Broccoli (cool-season heading brassica) is classed hardy in the cited extension guidance. The timing rules below are relative to your local freeze dates — enter a location to turn them into calendar dates.

The rules this site applies

Method	Frost-relative window	Rule & reconciliation
Start seeds indoors	10–8 weeks before the median last spring freeze	Sow 4–6 weeks before the set-out window opens (UNH 4–6 weeks; Missouri G6570 6–8 weeks).
Transplant outdoors	4–2 weeks before the median last spring freeze	UNH: set out 2–4 weeks before the last frost; Purdue's hardy class allows 4–6 weeks before. The later UNH range is used.
Fall planting	8–4 weeks before the median first fall freeze	Purdue Table 2: plant fall broccoli at least 4–8 weeks before the first fall frost.

Variety assumption: Assumes an average heading variety (about 60–70 days from transplant).

Crop rule sources (3)

University of New Hampshire Extension: Growing Vegetables: When to Plant Your Vegetable Garden [fact sheet] (accessed 2026-07-24)
Per-crop 'time from seed to transplant' and 'safe to set out in garden' relative to last frost.
University of Missouri Extension: Starting Plants Indoors from Seeds (G6570) (accessed 2026-07-24)
Weeks needed to grow vegetable transplants indoors (Table 2).
Purdue University Extension: Indiana Vegetable Planting Calendar (HO-186-W) (accessed 2026-07-24)
Hardiness classes: hardy = plant 4-6 wk before last spring frost; semi-hardy = 2-4 wk before; tender = after average last frost; very tender = at least 2 wk after. Table 2: fall planting at least 4-8 wk before first fall frost.

Reviewed city pages for broccoli