Sow spinach now for fresh greens well into winter
Mid-August opens the best sowing window for autumn spinach. Sow now and you'll be harvesting from October – and with one simple trick, well into winter.
Many beds start to empty out in August: early potatoes, onions and peas have been harvested, and the gaps are waiting for a sensible follow-up crop. This is exactly where spinach shines. It loves the shortening days, grows quickly and gives you a second harvest season when other crops have long called it a day.
Why August belongs to spinach
Spinach is a long-day plant with a clear preference for cool conditions: long summer days and heat make it bolt quickly, but from mid-August onwards the weather works in its favour. Days get shorter, nights get cooler – exactly the climate in which spinach produces tender, generous leaves instead of flower stalks.
On top of that, spinach is remarkably fast. Depending on variety and weather, the first leaves are ready to pick just six to eight weeks after sowing. Sow around mid-August and you’ll have fresh greens from October.
How to sow successfully even in summer heat
Sow spinach directly into the bed, about 2 to 3 centimetres deep, in rows spaced 20 to 25 centimetres apart. Within the row it can be fairly dense – thinning to 3 to 5 centimetres is enough.
One thing really matters in August: spinach seeds prefer to germinate in cool soil. If a heatwave is sitting over your garden, it helps to sow in the evening, water the drill thoroughly beforehand and keep the seeds evenly moist until they emerge. A shade net or a thin layer of mulch over the seed row keeps the soil cooler still. Once the seedlings are up, remove the cover.
The best spot: gaps left by early harvests
Spinach is the perfect gap-filler for beds where early potatoes, onions, garlic or peas have just been cleared. A moderate feeder with modest demands, it copes well with what’s still left in the soil – it doesn’t need fresh fertiliser.
It also plays nicely in companion planting: spinach is happy next to strawberries, cabbages or bush beans. Just keep it away from chard and beetroot – all three are close relatives from the same plant family and compete for the same nutrients. That’s also a crop-rotation argument: if chard or beetroot grew in the bed earlier this year, pick a different corner for your spinach.
Care: keep it moist, go easy on feeding
Until harvest, spinach needs one thing above all: even moisture. If the soil keeps drying out, the leaves turn tough and the plants may still bolt. So water regularly in smaller amounts rather than rarely and heavily.
When it comes to feeding, less is more. With a generous nitrogen supply, spinach stores more nitrate in its leaves. So skip fresh compost or manure right before sowing – a bed that just finished a summer crop has plenty to offer as it is.
Harvesting into winter
From about six weeks after sowing you can pick the outer leaves continuously – leave the heart standing and the plant will keep producing. Spinach tastes best freshly cut; it only keeps for a few days in the fridge.
And the winter trick? Spinach is surprisingly frost-hardy. A second sowing in early to mid-September with an overwintering variety establishes in autumn, pauses through the coldest weeks and delivers the very first harvest of the new year in early spring. A fleece cover helps the plants through hard frosts.
In Rootivo, the plant encyclopedia shows you at a glance how spinach’s sowing window shifts with your climate zone – so you hit the right moment even in harsher spots.
Im Lexikon: Spinat