Spinach is a cool-weather vegetable: it will produce abundantly in cool spring weather and again in fall (and throughout the winter in mild winter climates), but when the long hot days of full summer arrive, it sends up flowering stalk and stops producing its succulent dark-green leaves. For a fall crop, plant spinach in mid to late summer (too-warm soil can be an impediment). Young fall-grown plants, if protected with a thick layer of mulch, will often survive the winter even in cold climates, and put out new growth the following spring.
Sow spinach seed in spring as soon as the soil can be worked. It will germinate
in soils as cold as 40 degrees F (50 C). Loosen soil to a depth of 8 to 10
inches using a shovel or tiller. Mix in some compost or slow-release fertilizer
to provide plants with nutrients. Then rake the soil smooth, removing any large
clumps and rocks.
3. Grow. As seedlings grow, thin them by removing tightly crowded plants, using the small leaves in salads. Thin first to leave one plant every 2 inches. As the season progresses, thin the row to leave remaining plants 4 and then 6 inches apart. Keep seedbed moist until spinach germinates. Apply a layer of organic mulch, such as straw, to conserve moisture and keep soil cool. Pull weeds that sprout nearby.
Harvest spinach in the morning, when the leaves are cool and crisp. When plants
are rapidly growing, harvest individual leaves regularly, starting with the
outer leaves, as soon as they are big enough to use. When the days get warm,
spinach stems will begin to elongate. This is your cue to cut the entire plant
at the soil line. Start another crop in late summer for a fall harvest.
AT A GLANCE
Exposure: Full sun. Light shade may help prolong the harvest in summer.
Planting time: 4-6 weeks before the final frost. Sow again in late summer.
Planting depth: 1/4 inch deep
Spacing in row: Sow 1 inch apart; thin to 2 inches apart, and again later to 4-6 inches apart.
Time to harvest : 35 to 45 days, depending on variety.
Spinach grows well in containers.