Guv's Gardens
Photo: Rainer Haessner, CC BY-SA 3.0, via Wikimedia Commons
- Sun
- Full sun
- Soil
- Fertile, well-drained, not freshly manured
- Soil pH
- Around neutral, about pH 6.0-7.0; tolerates slightly alkaline soil
- Water
- Water in dry spells; stop once bulbs swell and ripen
- Hardiness
- Hardy; autumn-planted sets overwinter outdoors
- Height and spread
- 30-45cm tall
Guv's tipWater onions in dry spells, but stop once the bulbs swell and ripen. And don't plant them in freshly manured ground.
Through the year
Timings are for the UK as a whole. Northern and exposed gardens often run a couple of weeks later.
When to plant
Sow indoors from Jan (mid-winter to early spring) or outdoors in early to mid spring. Plant sets mid-Mar to mid-Apr, and overwintering sets Sep/Oct-Nov
Harvest or flowering
Autumn-planted sets Jun-Jul; spring-planted sets and seed onions Jul-Oct
Pruning
Remove any flower stems
Making more plants
Seed or sets
Watch out for
Allium leaf miner
Look for: Lines of white dots on leaves, distorted foliage, pupae in stems/bulbs
What to do: Cover with insect-proof mesh during adult flight periods (spring and autumn)
Onion fly
Look for: Maggots in bulbs, yellowing and wilting plants
What to do: Crop covers, rotate crops, remove affected plants
Leek moth
Look for: Caterpillars mining leaves, white patches and holes
What to do: Insect-proof mesh, remove affected leaves
Onion white rot
Stromatinia cepivoraLook for: Yellowing, wilting; white fluffy growth with black sclerotia on bulb base
What to do: No cure; do not grow alliums on infected ground for many years
Downy mildew
Various oomycetesLook for: Yellow patches above, grey/purple growth below leaves
What to do: Remove affected leaves, improve air flow, avoid wetting foliage
Leek rust
Puccinia alliiLook for: Orange pustules on leaves
What to do: Generous spacing, avoid excess nitrogen; resistant cultivars
Always read and follow the label on any treatment, and check it is approved for use where you live.
Safety and spread
Pets and people: Toxic to dogs, cats and horses: N-propyl disulfide causes haemolytic anaemia
Weed risk: None known
Growing somewhere else? See this plant for the USA.
The Plant Doctor and the Guv's book
Printable pest and disease charts with real photographs, and all 50 UK plants in one book.
