Spinach

Spinach is a cool-season green that's ready in about 37–45 days. Sow it as soon as the soil can be worked in spring and again in late summer, thin seedlings to 2–4 inches apart, and harvest before long, warm days make it bolt.

A 4×8 ft raised bed can hold several short rows, and succession sowings every couple of weeks keep leaves coming.

When should you plant spinach?

Twice a year. Illinois Extension recommends the first sowing as soon as the soil is prepared in spring, with more plantings over the following weeks, then another round in late summer for a fall and early-winter harvest.

Temperature matters for germination. Clemson Extension puts the ideal soil temperature at 70°F, and soil above 85°F inhibits germination — which is why midsummer sowings often fail.

How far apart should you plant spinach?

Sow 12–15 seeds per foot of row, ½ inch deep. When the seedlings are about an inch tall, thin to 2–4 inches apart. In a raised bed, rows can be as close as 12 inches.

Why does spinach bolt?

Long days and warm temperatures push spinach to flower. Once a seed stalk appears, the leaves turn bitter. To avoid it:

• Plant early in spring so the crop finishes before summer.
• Choose varieties labeled slow-bolting or long-standing for spring.
• Grow a fall crop, when days are getting shorter.

How do you harvest spinach?

Cut plants at or just below the soil surface while they're young — that's when quality is best. You can also pick the outer leaves and let the center keep growing. Harvest the whole crop as soon as a seed stalk starts to form.

Setting up a greens bed? The Raised Bed Soil Calculator sizes the fill, and the Drip Irrigation Calculator helps keep moisture even.

Sources: Spinach — Illinois Extension, Spinach — Clemson HGIC, Target Soil pH Values for Vegetable Crops — UMD Extension.