Spinach is the “emergency” vegetable of the balcony garden: from seed to first cut in 35–45 days, it tolerates cold, and with autumn sowing it accompanies you until March.
It is not a difficult crop, but it has two known quirks: slow germination in the cold and bolting in the heat. Both are solved with two moves. This guide covers sowing, pot, watering and harvest in an honest format: what really works in pots and what does not.
The full autumn calendar is in What to Sow in October.
Why spinach in pots works
- Short cycle: 35–45 days from seed to cut, even in autumn.
- Cold-tolerant: as a formed plant it holds −3 °C under shelter, and after the frost the leaves stay good (in fact, they sweeten).
- Continuous harvest: you cut and it comes back — one tray sowing lasts 2–3 months of spinach.
- Little space: the taproot is modest (15–20 cm), even a 20 cm tray is fine.
The only real limit in pots: summer heat. Above 25–27 °C bolting (the rush to flower) is a matter of days. That is why the useful sowings are two: spring (March–May) and autumn (August–November).
Varieties to choose
Look on the packet for two characteristics: early and slow to bolt.
- Matador: the most widespread, fast, big and crinkled leaves, good even in moderate heat. The organic 1,000-seed version is one of the best sellers on Amazon: organic Matador spinach seeds.
- Viroflay: similar to Matador, slightly more resistant to heat.
- New Zealand spinach (Tetragonia): attention, it is not Spinacia oleracea — it is a hardy perennial grown like lettuce. Pretty, but it is another plant: you find it as its own profile in New Zealand spinach.
For autumn sowings, always choose a packet that explicitly indicates sowing from August to November.
When to sow
| Period | Harvest | Notes |
|---|---|---|
| March–May | May–July | Classic: rising temperatures, fast germination |
| August–September | October–December | The best: fresh, regular cycle |
| October–early November | January–March | Works while the day has light; below 10 °C by day it slows down |
| Summer (June–July) | — | No: bolting in 2 weeks |
The germination trick: soaking
The spinach seed has a thick coat and germinates badly in the cold. The trick from the serious garden:
- Soak 12–24 hours in water at room temperature.
- Drain, dry on the surface, sow immediately.
Soaking softens the hard seed coat of spinach and speeds up and evens out germination. It is not a ritual: the imbibed seed breaks its coat sooner and starts.
Sowing and thinning of spinach in pots
- Moist substrate (not sodden), in a tray or pot of at least 15–20 cm depth.
- 2–3 seeds every 8–10 cm, at 1–1.5 cm depth.
- When they have 2–3 true leaves, thin to 15 cm: spinach is one of the few garden vegetables that you thin to eat the thinnings.
- In a 50 cm tray: 4 well-spaced plants, or 8 closer with leaf harvest.
Pot and substrate for spinach in pots
- Volume: for 4–6 plants, 10–15 L is enough; for a “garden-style” sowing (12+ plants), 25–30 L.
- Depth: 15–20 cm are enough for the taproot, but more substrate = more autonomy in winter.
- Composition: 60% potting mix, 30% expanded clay, 10% perlite. Spinach loves a fresh but well-drained substrate: crown rot is its enemy in pots.
Watering spinach in pots: the weak point
Spinach warns you with the leaves: if you see them “wilting” at midday, you are already late.
- Autumn–winter: 2–3 times a week, at midday.
- Spring: every 1–2 days, and on sunny days even twice.
- Never on the ground (on the leaves) in autumn: humidity + cold = spinach downy mildew.
The full routine with the finger check is in Watering in containers.
Feeding spinach in pots: nitrogen, but little
Spinach is a leafy: it wants nitrogen, but in pots less than in the ground.
- One dose of slow-release fertiliser at planting (see Feeding plants in pots).
- In autumn: that is enough. In spring: a second dose at mid-cycle.
- Deficiency signal: low leaves yellowing → nitrogen. In that case a liquid dose diluted to half strength, not full.
Frost and protection for spinach in pots
- Formed plant: −3 °C outdoors, without damage.
- Young plant (2–3 weeks): the frost kills it.
- With non-woven fleece on nights below 0 °C, the harvest window extends by 4–6 weeks.
The logic of the fleece (when to open, when to close) is in Protection from weather.
Harvest of spinach in pots: cut and it comes back
- First cut at 15–20 cm from the crown: cut with secateurs 2 cm above the crown, not flush — the growth heart must stay.
- It produces again in 3–4 weeks.
- When the flower shoots appear (bolting): the plant is at the end of its life. Cut everything, the heart is still edible, and sow the next one.
- Leaves after the frost: wash them cold and eat them — the sugar has concentrated, they are the best of the year.
Mistakes to avoid
- Sowing in June: bolting in 2 weeks.
- Sowing at 3 cm: in autumn it never germinates.
- Forgetting the soaking in October: germination at 50% and crooked plants.
- Watering in the evening in autumn: downy mildew on the crown.
Recommended products in this article
| Product | |
|---|---|
| organic Matador spinach seeds | View on Amazon |
| non-woven fleece | View on Amazon |
Sources
- CREA — Spinach (Spinacia oleracea): varieties, sowing and harvest (technical sheets)
- Orto da Coltivare — Spinach: growing guide, soaking and thinning
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