Plant onion seedlings or sets

When to do it

The calendar’s Onion window is for sowing seed. Transplant seedlings once ready in suitable local conditions; use local variety advice for sets, whose separate timing is not recorded in this calendar.

What you need

• Healthy seedlings or locally suitable sets
• Dibber and water
• Label

How to do it

1. Confirm the variety suits your location. A set is a small immature bulb, not the same as a seedling.
2. For seedlings, make a hole that holds the roots without bending them upwards. Plant at the previous soil level and firm gently.
3. For sets, place base down with the tip just showing, rather than burying deeply. Use approximately 10 cm spacing for ordinary bulb onions unless the variety specifies otherwise.
4. Water to settle and remove small weeds carefully; onion roots are shallow.
5. Check for disturbed sets, maintain suitable moisture and leave bulb shoulders exposed as they develop. Harvest when mature rather than forcing tops over.

What success looks like

• Plants root firmly and later form bulbs suited to the variety.

Watch out for

• Using any overseas onion variety regardless of day length.
• Planting bulb onions as deeply as leeks.

Plant guides using this technique

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