Ease of Growing [Scale 1-5] - 2 (Easy/Medium)
How Time Consuming
Once the ground is prepared and the onion sets are planted, a weekly hoe through the crop will be required. Regular watering in dry spells is required to prevent splitting, distorted growth or bolting (which means the crop has run to seed instead of putting growth into the bulb).
From onion sets:
- Stuttgarter Giant : suitable for all areas of the country, good taste, resistant to bolting and will keep well.
- Sturon : Large white onion, does not bolt and will keep for long periods.
- Rijnsburger : A very early round onion with resistance to bolting.
- Red Baron : This is a popular red onion, early to mature, bolt resistant and has a good colour.
Home Grown Vs Supermarket
A half kilo of onions sets will give you a good return. As well as the ability to go out and pull a fresh onion or for storing after harvest for regular use.
Best Sites and Soils
Onions will grow well in an open sunny site in soil that is moisture retentive but has good drainage. They will accept partial shade. Onions have a limited root system therefore improving the soil with well rotted manure or organic garden compost is invaluable. Onions do not thrive on acid soils below pH 6.5 so reduce the acidity by applying lime in autumn and winter. They can be grown on the same site year after year although it is good to practice crop rotation by moving them on yearly to a different bed on a 4 yearly cycle.
When to sow
From seed as soon as the soil is workable, sow in spring for a late summer crop or in late summer for an early summer crop the following year. Birds like to pull freshly planted sets from the soil, so it can be a good idea to cover the crop with fleece until the sets have rooted. Alternatively, sow your sets into seed trays until they have rooted and then plant out into their final growing space.
When to plant
Plant sets from early to mid-spring.
Distance between rows - 25cm (10”)
Distance between plants - 7.5-10cm (3-4”)
When to harvest
During the growing season apply a nitrogen rich organic fertiliser prior to any rainy spell.Close
Guide to sowing and planting - Push the sets into the soil the pointed end up with the tip just below the surface (to avoid the birds pulling them out).
Onions are susceptible to weed competition so ensure regular weeding especially in the early growing stage.
Cover with fleece immediately after planning to prevent the birds stealing the sets.
Problems to look out for - White Rot – leaves will turn yellow and the plant will wilt. White fluffy mould will grow at the base of the plant.
Rust – orange spots appear on the surface of the leaves which turn powdery. Leaves may turn yellow and die.