USA plant library · vegetable

Spinach

Spinacia oleracea · Amaranthaceae

Fast cool-season green

Photo: Sathya Madhu, CC BY-SA 4.0, via Wikimedia Commons

Sun: Full sun to part shade (shade helps in warm weather)
Soil: Moist, fertile, well-drained sandy loam high in organic matter
Soil pH: About 6.0-7.0 (neutral); sensitive to acid soils
Water: Keep consistently moist (soak to about 6 in). Drying out triggers bolting
Hardiness: Hardy cool-season annual. Tolerates about 15-20°F and can overwinter in mild areas
Height and spread: 6-12 in x 6-12 in

Guv's tipKeep spinach consistently moist, because drying out triggers bolting. Cut the outer full-size leaves and it'll keep regrowing.

Through the year

When to plant

Spring: 4-8 weeks before the last frost, once the soil reaches about 45°F (South Carolina Piedmont mid Mar-mid Apr, South Carolina coast Feb-Mar). Fall: 6-8 weeks before the first frost (South Carolina Aug-Oct)

Harvest or flowering

Harvest 28-55 days from seed in spring and fall. Bolts with long days and heat (in Pennsylvania the spring crop usually ends by late May-June)

Pruning

Cut the outer full-size leaves to encourage regrowth

Making more plants

Seed, sown direct 1/2 in deep

Watch out for

Pest

Aphids

Look for: Colonies on leaves; curling, sticky foliage

What to do: Conserve natural enemies; insecticidal soap or oils

Pest

Spinach leafminer

Look for: Tan, blotchy tunnels in leaves

What to do: Remove affected leaves, control weeds (lambsquarters), fine-mesh row covers; spinosad

Disease

Downy mildew

Peronospora effusa

Look for: Yellow patches on upper leaf, gray-purple growth beneath

What to do: Resistant varieties, avoid overhead watering

Disease

White rust

Albugo occidentalis

Look for: White blister-like pustules on leaf undersides

What to do: Rotation; control weeds and volunteer spinach; copper fungicide if needed

Always read and follow the label on any treatment, and check it is approved for use where you live.

Safety and spread

Pets and people: Low toxicity. Oxalic acid is harmful only in large quantities over time (NC State Extension: low severity). Dogs can eat small amounts, but the high oxalate content makes it a poor regular treat. Not listed by the ASPCA

Weed risk: Not on the federal noxious weed list. The USDA PLANTS database shows no federal or state noxious or invasive status

Checked against two or more reputable gardening sources. How we check our facts

Keep it by the back door

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