Spinach planting dates by zone

Why spinach bolts

University of Minnesota Extension says spinach is day-length sensitive: as the days lengthen it bolts, sending up a flower stalk, and hot weather or drought speeds that up. In Minnesota, it says, spinach tends to bolt in June even in cool weather, and long days challenge even slow-bolting varieties. University of Illinois Extension says spinach bolts quickly in the long days of late spring and summer, and warm weather speeds it.

So time it for short days. Clemson’s Home & Garden Information Center plants in early spring to avoid high temperatures and long days, and Minnesota says spinach sown in August for fall grows under shortening days and will not bolt.

Choosing a spinach

Clemson says most spinach grown in South Carolina is semi-savoy, meaning moderately crinkled, and that slow bolting matters for overwintered and spring plantings and downy mildew resistance matters too. It names ‘Bloomsdale’ (semi-savoy, slow bolting), ‘Tyee’ (semi-savoy, downy mildew resistant) and ‘Whale’ (savoy, downy mildew resistant, slow bolting).

Illinois says crinkled leaves catch soil in the rain, and suggests a plain-leaved variety to avoid gritty spinach. For the summer gap, Minnesota names heat-loving stand-ins with thick, tender leaves: Malabar spinach, a vine that needs a trellis, New Zealand spinach, orach and vegetable amaranth.

Sowing and thinning

Sow straight into the garden as soon as the soil can be worked, Minnesota says; Illinois sows as soon as the soil is prepared, and if it was prepared the fall before, broadcasts seed over frozen ground or snow in late winter to sprout as the soil thaws. The table dates sowing 6 weeks before each zone’s median last spring freeze, the offset our seed-starting tool uses.

Minnesota sows one-fourth to one-half inch deep in rows 18 to 30 inches apart and thins to two to four inches; Illinois covers the seed one-half inch deep, 12 to 15 seeds per foot, and thins to 2 to 4 inches when the plants are an inch tall. Clemson sows one-half inch deep and 2 inches apart in rows 1 to 3 feet apart, and says spinach seed more than a year old germinates poorly, so use fresh seed each year.

Keep sowing for a steady supply. Minnesota sows every one to two weeks in spring until the weather warms, and Illinois makes successive sowings for several weeks to keep the harvest going until hot weather.

Minnesota covers the seedlings with floating row cover against cold and insects, then switches to a lightweight mesh that still keeps out flea beetles and leaf miners.

Fall and winter spinach

Minnesota sows fall spinach about two months before the average first frost; in most of the state it waits until mid-August to avoid summer heat, earlier from Duluth north. Illinois sows again in late summer for a fall and early winter harvest, and chills the seed in the refrigerator for 1 or 2 weeks before summer or fall sowings.

Spinach is hardy. Clemson says it can be harvested through the winter and into spring in South Carolina, and Illinois says that in southern locations young plants survive the winter on well-drained soil and resume growth in spring; with mulch, it says, gardeners on the edge can coax seedlings through. Illinois also grows it in low tunnels and cold frames.

The table’s last fall sowing counts back 16 days from each zone’s median first fall freeze: our crop table’s 40 days to harvest less the 24 days of frost it takes. Minnesota’s two months is the more cautious figure.

Soil, water and feeding

Spinach dislikes acid soil. Clemson says it is sensitive to acidic soils and keeps the pH between 6.0 and 7.0; Minnesota grows it at a pH between 6.5 and 8. Clemson prefers a fertile sandy loam high in organic matter, and raised beds about 3 inches high reduce damping-off.

For quality and to delay bolting, Minnesota gives spinach enough water, soaking the soil thoroughly at least once a week if it gets less than an inch of rain. Clemson waters in the morning to moisten the soil 6 inches deep, and says not to pull soil toward the plants, because leaves covered with soil rot. Illinois side-dresses with nitrogen only if growth is slow or the leaves are pale.

Southern timing

Clemson’s planting table gives the South Carolina Piedmont March 15 to April 15 in spring and August 1 to September 30 in fall, and the Coastal Plain February 1 to April 1 and August 15 to October 15.

Texas A&M AgriLife’s home vegetable gardening guide sows spinach 1 to 8 weeks before the frost-free date in spring and 2 to 16 weeks before the first freeze in fall.

Harvest

Clemson says spinach is ready about 37 to 45 days after planting, and picks dark green leaves 3 to 6 inches long, outer leaves first. Illinois cuts whole plants at or just below the soil once they have five or six leaves, or picks outer leaves at 3 inches and lets the young ones grow.

When bolting starts, harvest it all. Minnesota says that if one plant bolts the rest will soon follow, and Illinois says the leaves deteriorate quickly once seed stalks form.

Common problems

Illinois says downy mildew and other fungal leaf diseases are worst in wet, humid seasons, and that resistant varieties and raised beds help; Clemson names downy mildew, white rust and seedling damping-off, and uses resistant varieties against downy mildew.

Illinois says yellowing, stunting and early death come from blight, which is cucumber mosaic virus, and the answer is resistant varieties. Clemson says aphids matter most because they spread viruses, and lists cutworms, cabbage loopers, corn earworms and diamondback moth caterpillars too.

Common mistakes

• Sowing in late spring. Minnesota and Illinois say the lengthening days make spinach bolt.
• Old seed. Clemson says spinach seed more than a year old germinates poorly.
• Acid soil. Clemson says spinach is sensitive to it.
• Letting the bed dry out. Minnesota says drought speeds bolting.
• Hilling soil onto the plants. Clemson says leaves covered with soil rot.
• Leaving bolting plants in the row. Minnesota says the rest will soon follow.

We found no Florida spinach source on UF/IFAS Gardening Solutions, and no source for Louisiana, Alabama or Mississippi, that we read for this page. The Southern timing here is Clemson’s and Texas A&M AgriLife’s.

Questions

When should I plant spinach in spring?

As soon as the soil can be worked, University of Minnesota Extension says. The table on this page gives a date 6 weeks before each zone’s median last spring freeze, from NOAA records.

Why does my spinach bolt so fast?

Minnesota says spinach responds to lengthening days by sending up a flower stalk, and heat or drought speeds it; in Minnesota it bolts in June even in cool weather. University of Illinois Extension says to choose long-standing, slow-bolting varieties for spring.

When should I plant fall spinach?

Minnesota sows about two months before the average first frost and says August-sown spinach grows under shortening days and will not bolt. Clemson’s fall window in the South Carolina Piedmont is August 1 to September 30.

Can spinach survive winter?

Often. Clemson says spinach can be harvested through the winter and into spring in South Carolina, and Illinois says young plants survive the winter on well-drained soil in southern locations, with mulch helping further north.

What can I grow instead of spinach in summer?

Minnesota names heat-loving stand-ins: Malabar spinach, which needs a trellis, New Zealand spinach, orach and vegetable amaranth.

Sources

Freeze dates on this page are NOAA 1991–2020 Climate Normals, for every station the ZIP codes in each zone cite. Zones are the USDA Plant Hardiness Zone Map, 2023. The planting rules are named beside the table. Growing advice is quoted from the extension publications below, each written for its own area.

• University of Minnesota Extension, Growing spinach and Swiss chard in home gardens , by Marissa Schuh and Jill MacKenzie (Reviewed 2022). Written for: Minnesota (USDA zones 3a–5a).
• University of Illinois Extension, Spinach (Home Vegetable Gardening) . Written for: Illinois (USDA zones 5a–7a).
• Clemson Cooperative Extension, Home & Garden Information Center, Spinach (HGIC 1320) (Revised May 7, 2020). Written for: South Carolina (USDA zones 8a–9b).
• Texas A&M AgriLife Extension, Texas Home Vegetable Gardening Guide (EHT-077) , by Joseph Masabni (June 2014). Written for: Texas (USDA zones 6b–10b).

How we write our guides

Published October 27, 2026