How to Plant Autumn Onions

October  is the perfect time to plant Autumn onion sets and garlic. In this post I will share how to plant autumn onions.

We have two  varieties of onion in stock for you:
Autumn Champion – a brown onion which is one of the best autumn and winter varieties, producing high yields which store well. A good all purpose cooking variety.

Red Winter – a red tinged skin with good flavour and excellent keeping qualities. Crisp and sweet and perfect for stir fries and salads.

We also have Elephant Garlic ready and these can also be planted now. The Garlic variety Kingsland Wight is due in soon. This always sells out very quickly so if you’d like us to reserve any for you please contact the shop on 01835 830315.

If you need advice on how to grow garlic please check out our “How To Grow Garlic Guide” here.

If you’ve never tried growing autumn onions before – just read on….

How to Grow Autumn Onions

Onion sets are small immature onions, which have been grown from seed in the previous year, and then harvested early so that they can be planted out a later date. Autumn planted sets will provide the grower with a distinct advantage of an early harvest in the following year.

Growing in containers

Onions can be grown in beds or containers. Growing onions from sets in containers is ideal for those who want a small, steady supply of bulbs as and when needed, with any surplus being dried and stored for later use. Make sure that the posts selected have good drainage holes, and raise them up on pot feet to prevent waterlogging. Fill large pots or containers with good quality compost such as Growmoor Vegetable Compost. Firm the soil surface and apply water with a watering can and rose attachment. Use a dibber or gently push the sets into the soil, at 10cm spacing, so that only the tips are visible. Place the container in a sunny position.

Growing in beds

Prepare planting beds, usually after other main crop vegetables have been harvested, and incorporate plenty of organic matter. Onions will grow best in well-drained soil in a sunny position. Rake the surface soil to a fine tilth and firm with the back of a rake. Push the sets into the soil so only the tips are showing. Space each set at 10cm apart in the rows and 30cm between the rows. If the birds pull them out, just keep pushing them back in until the roots are sufficiently formed to anchor them on place.

General aftercare

If the autumn is mild then the sets will begin to show signs of growth with green shoots appearing. Onions are very hardy but if early hard frosts are forecast then ensure these young shoots are protected with frost fleece. Water sparingly and only if the soil dries out, otherwise they should over winter without any problems. Water as normal when temperatures rise during late spring.

Pests and diseases

Over winter, the onions will be dormant and pests and diseases will be less troublesome. Come the spring, look out for signs of yellowing leaves, rust, mildew and mould.  Avoid feeding young plants with nitrogen-rich fertilisers. Onion fly is a known pest but rarely affects plants grown from sets.

Harvesting and storage

Autumn planted onion sets should be ready for harvesting from early June in the following year, which is 2-3 months ahead of spring planted sets. Store in a cool dry place.