Choose a sunny, sheltered spot that doesn’t get too waterlogged. Fertile soil helps, so add plenty of compost before planting.
You can grow onions really well in a raised bed or traditional veg plot, and also in pots – choose pots that are oblong in shape as this works well.
Plant 15cm apart.
To plant onions from set: Plant in Feb/Mar. Push each bulb into the soil, with the hairy root side pointing down, until they are deep enough that their tip is just below the surface of the soil.
To plant onions from plants: If there are multiple seedlings per plug, you can carefully tease these apart before planting as normal.
Growing Tips:
During dry spells, water well to prevent the soil from drying out and to keep the soil a little cooler.
Keep onions weed-free as much as possible. Using an onion hoe for regular weeding is best as this allows you to get in amongst the plants without disturbing their roots.
Problems & Pests:
Brown/orange spots on leaves – this is likely to be rust, a fungal disease that affects plants like leek, onion and garlic. If you do see it on onions, then it is best to harvest your crop before it worsens and cut off affected foliage before drying them out.
Harvesting/Storing:
You can expect to harvest your onions any time between late June and mid August.
Wait until you see the leaves turn yellow, then harvest on a dry sunny day. Lay them out in a greenhouse (or sunny windowsill, or out in the sunshine if it is dry in the forecast for a few days) to let the skins harden. This will take up to 14 days normally. After that you can store them in a cool dry place for several weeks/months.
