How to Grow Spinach: Planting, Spacing, Care & Harvest
Quick answer
Sow spinach early in spring after soil reaches about 45 degrees F (UMD), or about 2 to 3 weeks before the last frost (USU). For fall, sow about two months before the first frost (UMN) or use the planner fall window. Thin to a few inches apart, keep moisture even, and use row covers against leafminers.
Spinach at a glance
Weeks relative to last frost (LF). Colored weeks show when our ZIP planner schedules each step.
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Planting dates for your ZIP: the ZIP planting planner counts each window from your local frost dates.
Organic pests and diseases: see also organic pest control. Use any product as the label directs.
True spinach (Spinacia oleracea) is not the same plant as New Zealand spinach, Malabar spinach or Okinawa spinach.
Planting timing
UMD: hardy annual; “Sow seed early in the spring after soil temperatures have reached 45°F.” Succession: “Make several small plantings several days apart.” Fall crop with protection into December (UMD Extension). UMN: sow as soon as soil is workable in spring; succession every 1–2 weeks until outdoor temps reach about 80°F. Fall: “sow seed two months before the average first frost date” (UMN Extension). USU: plant seeds ½ inch deep, 2–3 weeks before the last frost in spring; fall plant 50–75 days before anticipated maturity (Utah State Extension). Bolting: long days and heat; UMN notes multiple days above about 75°F push flowering.
Depth and spacing
UMD: space 3 inches apart in rows or equidistant in wide beds; thin by cutting every other plant to about 6 inches for full-size leaves. UMN: seed ¼ to ½ inch deep; rows 18 to 30 inches; thin spinach to 2 to 4 inches. USU: seed ½ inch deep; 3 inches in-row; rows 12 inches. Sources differ on finish spacing and row width — show each.
Sun, soil and water
UMD: tolerates partial shade (4–6 hours) but grows well in full sun in spring/fall. UMN: pH 6.5 to 8; compost/well-rotted manure; no “Weed and Feed.” Water: UMD keep uniformly moist; UMN about 1 inch rain/week; USU 1–2 inches per week. Fertility from organic matter — do not print synthetic NPK rates. Soil test first.
Care
Row covers: UMD exclude leafminers, speed growth, extend season. UMN floating cover for cold and insects; lightweight mesh in heat still blocks flea beetles and leafminers. Weeds: spinach competes poorly (UMD; USU); shallow cultivation; mulch.
Harvest and storage
Days to maturity: UMD 28–55 from seed; Clemson planning citation in plants.json 40–60 — show both. UMD: cut full-size leaves to encourage new growth from the crown; final harvest when flower stalks rise. Storage 2 to 3 weeks at 32°F, 95% RH (UMD). USU: strip older leaves first or cut to within 2 inches of soil if growing point intact.
Pests and diseases (organic)
Spinach / beet leafminers: blotch mines on Chenopodiaceae. Remove/destroy first mined leaves and eggs; rotate; row cover on clean ground; weed hosts. Organic: spinosad at/before egg laying per label (UMD Extension).
Flea beetles, aphids, slugs: floating row covers for flea beetles; insecticidal soap or strong water spray for aphids; reduce moist harborage and use labeled slug products as directed (USU; UMN).
Downy mildew: purple-gray fuzz usually on leaf undersides; yellow then tan tissue above. Cool temps, long leaf wetness. Cultural: minimize leaf wetness; irrigate early; drip when feasible; rotate spinach land 2–3 years; destroy crop after harvest (Cornell Vegetables). Resistant cultivars help but races change — no named variety list.
Cercospora leaf spot: rotate 3 years; remove debris; mulch; water at base; pick infected leaves (UMD Extension).
Related: what vegetables to plant in fall · organic pest control · ZIP planner · how to grow beets · Malabar spinach · New Zealand spinach
Frequently asked questions
When do I plant spinach for fall?
UMN: about two months before average first frost. USU: 50–75 days before a maturity date about 1–2 weeks after first frost. Site planner fall sow is first frost minus 7 to 4 weeks. Label each.
How do I stop leafminers without synthetic calendar sprays?
Row cover on rotated ground, remove egged/mined leaves, control chenopod weeds; spinosad only per label at egg-lay timing (UMD).
Why did my spinach bolt?
Long days and heat (often multi-day stretches above about 75°F) (UMN; USU).
More grow guides: Carrots · Strawberries · Shallots · Raspberries · Sweet Corn · Beets · Dill · Bok Choy · Brussels Sprouts · Collards · All grow guides
Sources
- University of Maryland Extension: UMD Extension; UMD Extension; UMD Extension
- University of Minnesota Extension: UMN Extension
- Utah State University Extension: Utah State Extension
- Cornell University Vegetable Program: Cornell Vegetables