Spinach is one of the earliest vegetables you can get in the ground each spring — and one of the last still producing in fall. It thrives in cool weather and tolerates frost, which gives you a longer growing window than most vegetables. Get the timing right and you can harvest fresh spinach for 10–12 weeks per season, sometimes more.
This guide gives you exact planting dates by USDA zone for both spring and fall crops.
When to Plant Spinach by Zone
Spinach grows best in temperatures between 35°F and 65°F. For spring plantings, sow seeds directly outdoors 4–6 weeks before your last frost date — spinach seeds germinate at soil temperatures as low as 35°F. For fall plantings, count back 6–8 weeks from your first fall frost date to find your ideal sowing window.
| USDA Zone | Spring Planting | Fall Planting |
|---|---|---|
| Zone 3 | Apr 14 – Apr 28 | Jul 21 – Aug 4 |
| Zone 4 | Apr 4 – Apr 18 | Aug 7 – Aug 21 |
| Zone 5 | Mar 19 – Apr 2 | Aug 21 – Sep 4 |
| Zone 6 | Mar 4 – Mar 18 | Sep 5 – Sep 19 |
| Zone 7 | Feb 22 – Mar 8 | Sep 23 – Oct 7 |
| Zone 8 | Feb 6 – Feb 20 | Oct 3 – Oct 17 |
| Zone 9 | Jan 20 – Feb 3 | Oct 17 – Oct 31 |
| Zone 10 | Jan 1 – Feb 1 | Nov 1 – Nov 20 |
Spring Planting: Sow Early and Often
Spring spinach is a race against the heat. Once daytime temperatures regularly exceed 75–80°F, spinach bolts and turns bitter. Your goal is to get seeds in the ground as early as possible so the plants have time to produce multiple harvests before that happens.
In zones 5–7, this typically means sowing in early to mid-March — even if the ground is still cold. Spinach seeds germinate in soil as cold as 35°F, though germination is faster (7–10 days) at 50–60°F versus 2–3 weeks at 35°F.
Sow a short row every 2 weeks from your first sowing date until 6 weeks before your expected summer heat arrives. This succession planting approach gives you a continuous harvest rather than one big flush.
Fall Planting: The Sweeter Season
For many gardeners, fall spinach is the highlight of the cool-season garden. The plants establish in late summer, then produce abundantly as temperatures cool. Fall frosts actually improve spinach flavor — the plant converts starches to sugar in response to cold, making leaves noticeably sweeter.
The challenge with fall spinach is getting seeds to germinate in late-summer heat. Soil temperatures above 85°F inhibit germination. Tricks that help: water the seed bed well and keep it moist, sow in the shade of a taller crop, or lay a board over the bed for a few days until germination begins (remove immediately after sprouts appear).
In zones 6 and warmer, spinach sown in fall can overwinter under row cover and provide early spring harvests before new plantings are ready — making it nearly a year-round crop.
Varieties and Days to Maturity
For spring plantings, bolt-resistant varieties are essential. Look for varieties labeled “slow to bolt” or with long standing times: ‘Space’ (40 days), ‘Tyee’ (45 days), ‘Melody’ (42 days). These give you more harvest time before the heat triggers flowering.
For fall plantings, flavor and cold hardiness matter more than bolt resistance. ‘Bloomsdale Long Standing’ (48 days) and ‘Regiment’ (37 days) are excellent fall choices.
Quick Planting Tips
Sow seeds 1/2 inch deep, 2 inches apart in rows 12 inches apart. Thin to 4–6 inches once seedlings are 2 inches tall. Spinach prefers rich soil with a pH of 6.5–7.0 — it doesn’t do well in acidic conditions. Add lime if your soil is below 6.0. Keep soil consistently moist; irregular watering accelerates bolting.
