Spinach

Spinacia oleracea · Amaranth family (Amaranthaceae)

At a glance
Hardiness zones	2 to 11
Sun	full sun to part shade
Water	moderate
Life cycle	annual
Frost	Hardy: takes frost
Soil pH	6.5–8.0
Spacing	2 to 4 inches
Days to harvest	40 to 60 days
Soil temperature to plant	at least 40°F

About Spinach

Spinach is a fast, cold-tolerant leafy green for early spring and fall. Long days and warm weather make it bolt, so it is best sown early and again in late summer.

Grown as a cool-season annual in every zone; time it for the cool weather of spring or fall. Mulched plants with 4 to 5 true leaves can overwinter.

When to plant

Timing is counted from your average last spring frost (and first fall frost). Sow & Tell works out the actual dates for your ZIP code.

Sow seeds outdoors: 2 to 6 weeks before the last frost
Fall planting: 4 to 8 weeks before the first fall frost

Days count from seeding. Sow every 1 to 2 weeks in spring until it turns hot; several days above 75F, long days or drought will make plants bolt.

Soil

Fertile, well-drained soil rich in organic matter; spinach tolerates neutral to slightly alkaline soil.

Follow a soil test and keep pH 6.0 to 7.0 (spinach dislikes acid soil); work in no more than about 1 inch of compost and till any pre-plant fertilizer about 6 inches deep.

Feeding

3 to 4 weeks after planting, around thinning time: nitrogen fertilizer such as calcium nitrate (15.5-0-0) or 21-0-0. Use about 1 lb of calcium nitrate per 100 sq ft (30 ft of row), or 1/4 cup of 21-0-0 per 10 ft of row, 4 to 6 inches from the plants, and water it in; split it in two on sandy soil.

Keep fertilizer off the leaves and away from the stems to avoid burn; do not use weed-and-feed products.

Harvest

Pick outer leaves once they reach usable size, or cut the whole plant about 2 inches above the soil, any time before the flower stalk forms.

Pick single leaves while they are small and the plant grows new ones for several harvests. Once one plant starts to bolt the rest soon follow, so harvest them all then.

Varieties (28)

Variety	Type	Days	Notes
Whale	Hybrid		Round, dark, uniform leaves. Slow to bolt, with resistance to many downy mildew races.
Ozarka II	Savoy		Open-pollinated, medium-curled savoy spinach for fall planting where white rust is a problem.
Regiment	Savoy	37 days	Fast savoy spinach recommended for Central Texas.
America	Savoy (Bloomsdale type)		Deep dark green Bloomsdale type that matures later than others. Extremely slow to bolt and suited to spring sowing under long days.
Bloomsdale Long Standing	Savoy (crinkled leaf)	48 days	Wisconsin Extension calls it one of the best-tasting spinach varieties. Crinkled, dark green leaves. Slow to bolt, so it suits late-spring and early-summer sowings. Has no disease resistance.
Ambassador	Savoy, hybrid		Vigorous hybrid with dark green, heavy, fully savoyed leaves on semi-upright plants.
Regal	Semi-savoy	30 days	Quick semi-savoy suited to dense sowings for baby leaves. Resists downy mildew races 1 to 7.
Avon	Semi-savoy, hybrid	44 days	Dark green hybrid for early spring sowings. Tolerates blight and mildew.
Chesapeake	Semi-savoy, hybrid	45 days	Vigorous, winter-hardy hybrid that can overwinter. Fairly slow to bolt.
Coho	Semi-savoy, hybrid		Upright, fast-growing hybrid with dark green leaves. Slow to bolt.
Emperor	Semi-savoy, hybrid		Dark green, upright hybrid with round to oval leaves. Good for baby leaf.
Grandstand	Semi-savoy, hybrid		Hybrid that is slow to bolt, suited to spring planting.
Melody	Semi-savoy, hybrid	42 to 43 days	Dark green, lightly crinkled leaves. Resists downy mildew races 1 and 2 and cucumber mosaic virus.
Skookum	Semi-savoy, hybrid	41 days	Fast-growing, long-standing hybrid with dark green, upright leaves.
Tyee	Semi-savoy, hybrid	39 to 42 days	Thick, dark green leaves on a fast-growing hybrid. Very slow to bolt and tolerates downy mildew races 1 and 3.
Correnta	Smooth leaf		Long-standing, smooth, oval, dark green leaves. Resists downy mildew races 1 to 3.
Corvair	Smooth leaf	40 days	Smooth-leaved spinach with resistance to downy mildew races 1 to 11.
Giant Nobel	Smooth leaf		Large-leaved spinach.
Lizard	Smooth leaf		Smooth-leaf spinach recommended in Georgia and North Dakota.
Seaside	Smooth leaf		Smooth-leaf spinach recommended for Georgia that performed well in North Dakota trials.
Viroflay	Smooth leaf		An older smooth-leaved spinach.
Olympia	Smooth leaf, hybrid	46 days	Fast-growing, dark green, smooth leaves. Very slow to bolt and tolerates downy mildew races 1 to 3.
Red Kitten	Smooth leaf, hybrid		Medium green, round, smooth leaves with bright red stems and veins.
Space	Smooth leaf, hybrid	29 to 39 days	Smooth-leaved hybrid that resists bolting and downy mildew.
Acadia		45 days	Dark green spinach that resists bolting.
Dixie Market			Fast-growing, compact, upright plants with dark green leaves, released by Texas and the USDA in 1957. Resists blue mold and spinach blight.
Teton			Utah State lists it among the spinach varieties that suit local conditions.
Winter Bloomsdale			A Bloomsdale type that UGA recommends for Georgia gardens.

Good neighbors

Tomato, Pepper (sweet and chili)

UMN Extension suggests sowing spinach early among later tomatoes and peppers to save space; there is no pest-control claim.

Pests to watch for

Leafminers, Flea beetles, Slugs, Aphids, Cutworms, Garden symphylan, Beet armyworm, European corn borer, Seedcorn maggot, Deer, Voles

Diseases and problems

Downy mildew, White rust, Leaf spots, Bolting (going to seed), Nitrogen deficiency, Herbicide injury, Mosaic viruses, Damping-off, Cercospora leaf spot, Sooty mold, Cucumber mosaic, Curly top, Lettuce mosaic, Turnip mosaic

In the kitchen

Eaten raw in salads or cooked in soups, pastas, egg dishes and sautes.

Keeping it: Keep spinach cold and moist in a bag in the fridge and use it within about 10 days. Wash it well just before using.

Safety: If you take the blood thinner warfarin, keep the amount of greens like spinach about the same from day to day, because they are rich in vitamin K (NIH Office of Dietary Supplements).

Pets: Not listed as toxic by the ASPCA

Sources

Photo: Photo: Алексей Тараканов, CC BY-SA 2.0, via Wikimedia Commons (CC BY-SA 2.0). Photo resized for the web.

Planting dates and advice are general guidance; check with your local Cooperative Extension office for your area.