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Plant · Grow it at home

Spinach.

Spinacia oleracea · cool-season leaf that answers to the calendar

Spinach bolts on the calendar as much as the thermometer: as the days lengthen it runs to flower and the leaves turn bitter. Heat and dry soil bring that forward, so watering helps — but it only buys weeks. The reliable sowing is the late-summer one, into shortening days.

What spinach needs

Needs radar

Light Warmth Water Humidity Space

How demanding spinach is on each axis — the shape you learn to read across every plant.

Conditions at a glance

  • Light Sun early in the year · light shade once it warms
  • Warmth Cool-season · flowers as the days get longer
  • Humidity Not fussy
  • Water Keep it moist — dry soil brings the bolting forward
  • Pot size A container at least 30 cm wide and deep
  • First harvest Baby leaves ~1 month · mature leaves ~2 months

Grow it in your space

  1. Sow 2.5 cm deep along a shallow drill, with rows 20 cm apart, and thin the seedlings to about 7.5 cm once they are big enough to handle.
  2. Sow again in late summer or early autumn. That is the sowing that actually works: those plants grow into shortening days, so the signal that makes spinach flower never arrives.
  3. In a container, use one at least 30 cm across and deep. A shallow pot dries out between waterings, and dry soil is one of the things that sends spinach to seed early.
  4. From late spring, keep it out of the hot midday sun. Light shade does not stop bolting, but it buys real weeks.
  5. Sow a little and often — every week or two — rather than one long row, and stop once the weather is properly warm. Above about 27 °C there is no point starting more until autumn.
  6. For winter and very early spring picking, sow a hardy variety in early autumn and cover it with a cloche or fleece from October.

How to tell it's ready

  • Baby leaves about a month after sowing — the fastest return on the whole bed. Sown thickly and cut young, spinach is a salad crop long before it is a cooking one.
  • A few leaves from each plant, not the whole plant — work along the row taking the outer leaves and the centre keeps producing — the same habit that makes chard and lettuce last.
  • Usable size, not a date — pick a leaf as soon as it is worth picking. Spinach cooks down to almost nothing, so harvest more than looks sensible.
  • When it bolts, take everything at once — the leaves will not improve from here, so cut the lot, use what is good, and start the next sowing. This is the plant finishing, not you failing it.

Watch-outs

  • Bolting — a flower stem shoots up and the leaves turn bitter for good. Lengthening days are the trigger; heat and dry soil pull it forward. Bolt-resistant varieties help in spring but do not make it a summer crop.
  • Leaf miners — pale winding tunnels or dry patches inside the leaf. Pick off the affected leaves — the plant carries on and the rest is perfectly good.
  • Downy mildew — yellow patches with a greyish bloom underneath, in crowded damp plantings. Thinning to the proper spacing is most of the cure.
  • Slugs, snails and pigeons — seedlings disappear overnight and pigeons strip larger plants. Netting or mesh for the first few weeks handles both.

Varieties & a little history

Bolt-resistant summer types — worth it for a spring sowing, though they only delay itHardy overwintering types — sown in early autumn for winter and the earliest spring pickingBaby-leaf types — sown thickly and cut young for saladPerpetual spinach — not a spinach at all: it is chard, and it keeps going when real spinach has bolted

There are two spinach seasons, and only one of them is easy — which is why the crop has a reputation it does not quite deserve. Spring spinach is a race against daylight. It is sown into lengthening days, and lengthening days are the signal that tells the plant to flower; warm weather makes it respond faster still. In a northern summer there comes a point — around midsummer — where it will bolt whatever variety you chose. Autumn spinach has the opposite experience: sown in late summer, it grows into days that are getting shorter, so that signal never arrives, and under a cloche it will hold through the winter and give you the first real picking of the following spring. Most people meet spinach in the hard season first, decide they cannot grow it, and are wrong by one sowing date.

Will spinach grow where you are — and when to sow? →

New to this? Start with your first balcony season, check your growing zone, then let the planner turn it into a dated plan for your spot.

Data honesty: the care ranges here (sun hours, temperature, pot size, radar shape) are drawn from reputable horticulture sources and are checked before publish — the radar is only as trustworthy as its underlying numbers. Growing is a conversation with your own space, not a formula.

Sources

Educational guidance, not a guarantee — your own microclimate, soil, light and water have the final say. Last reviewed 2026-08-13. Growmanac makes no edibility or health claims.