Green onion.

Conditions at a glance

• Light Full sun
• Warmth Cool-season · hardy varieties overwinter outdoors
• Humidity Not fussy
• Water About 2.5 cm of water a week — steady, not soaking
• Pot size A pot at least 30 cm wide; depth is not the issue
• First harvest About 2 months from sowing

Grow it in your space

1. Pick a sunny spot with light, free-draining soil or peat-free compost. Onions of every kind want sun.
2. Make a shallow drill about 1 cm deep, water along the base, then sow the seed thinly and cover.
3. Space rows about 20 cm apart. In a pot, a few short rows or a scattered band works just as well.
4. Thin the seedlings to roughly 2.5 cm apart as they grow — the thinnings go straight into a salad, so nothing is wasted.
5. Water steadily, around 2.5 cm a week. Pots dry out faster, so check them rather than following the calendar.
6. Sow a small batch every couple of weeks. One long row all at once gives you a glut and then nothing.

How to tell it's ready

• About 15 cm tall with a bulb no wider than 1–2.5 cm — that is the sweet spot. Once the base starts swelling much beyond that, texture and flavour both go the wrong way.
• Loosen the soil before pulling — a trowel under the row first — pulled dry and hard, the stalk snaps off and leaves the base behind.
• Take alternate plants first — harvesting every other one gives the rest room to size up, so a single sowing gives you two pickings instead of one.

Watch-outs

• Sown once, all at once — the single most common mistake with this crop. They mature together, so a big sowing means a fortnight of plenty and then an empty bed. Small, frequent batches are the whole technique.
• Left too long — they get tougher and stronger-flavoured with size. This is not a crop that rewards patience — pick while young.
• Crowding — unthinned seedlings compete and stay thin and weak. Thinning feels brutal on such small plants; do it anyway.
• Shade — all onions want full sun. In a shaded spot you get pale, floppy growth and a long wait.