Sowing spinach: germination and successive harvests
In the UK, sow spinach in cool weather in mid to late spring or late summer to early autumn. Choose a hardy variety for an overwintering crop, then thin seedlings and pick leaves in succession.
By Marmanda3 min read
Spinach is best sown directly outdoors in cool weather. For UK gardens, the RHS recommends mid to late spring for late-spring and summer leaves, or late summer to early autumn with a hardy variety for autumn or early-spring picking. Follow the sowing and thinning method below.
Choose a window that avoids heat and deep cold
The RHS notes that very hot or very cold weather can impair germination; hot, dry conditions can also trigger bolting. Avoid sowing into extremes, and wait until late-summer heat eases before starting an autumn row. For overwintering, choose a hardy variety and sow early enough for plants to establish before winter. Lengthening days can also prompt bolting, so a spring crop may finish sooner as the season advances.
The French SNHF spinach page gives March–April and August–September as French reference windows. The RHS spring and late-summer guidance above is for the UK. Let soil and temperature conditions guide the date rather than copying a month from another region.
Prepare and sow a direct row
Choose an open site in sun or partial shade and prepare the bed ahead of sowing. Weed the row, loosen the soil and remove clods that would obstruct the seedlings. The RHS method is to sow 2.5 cm deep in drills 20 cm apart. Leave enough room to reach the crop and keep the bed clear.
Water the row after sowing if the soil is dry, then keep it evenly moist while seedlings emerge. Avoid waterlogging, especially in cool weather. Direct sowing is the usual method: the RHS notes that transplant disturbance can make spinach more prone to bolting. If you need an earlier start, sow individually in modules in early spring to minimise root disturbance before planting out.
Thin plants before they crowd each other
When seedlings are large enough to handle, thin them to 7.5 cm apart and remove smaller, weaker plants. A few weeks later, the RHS suggests harvesting every alternate plant for salads, leaving the rest with more room. If you want baby leaves rather than mature plants, thinning may not be needed.
This gives you two useful choices. For mature plants, thin early and leave the crop to fill out; for small leaves, sow a short row and pick young. Do not pull at the roots of neighbouring plants while thinning. Water lightly after working if the surface has dried.
Make repeat sowings for a longer season
For a steady supply, the RHS recommends sowing small batches every few weeks in spring and again in late summer or autumn, as conditions allow. It notes that flat-leaved varieties tend to cope better with warm weather than Savoy types. A partly shaded spot among taller crops can also offer cooler conditions during warmer weather. Keep each sowing labelled: when one batch bolts or finishes, you can see which timing worked better.
Pick outer leaves while leaving the centre intact, or harvest alternate plants whole to create room for those left behind. The SNHF gives about two months from sowing as a French harvest reference; actual timing depends on variety and growing conditions. Avoid treating that duration as a UK date forecast.
Use the vegetable sowing and planting calendar to place successive rows through the year. What to plant in September and what to plant in October offer seasonal context for autumn sowings.
References: RHS, Spinach; SNHF, Épinard (in French).