Many of you will now have harvested your onions, shallots and garlic, however the growing season is not yet over. Some varieties are much more tolerant of cold weather and can be planted from August to early September for a crop in June. These autumn planting onions, shallots and garlic are ideal for extending your growing season and are grown in exactly the same way as your spring planting varieties.
How to grow
If you’ve never grown onions, shallots or garlic in the autumn, don’t be put off. The technique is essentially the same except what you’re looking for is late maturing varieties that are more resistant to bolting. Soil preparation, as with any crop, is the key to success. The soil should be free draining, so if you suffer from heavy clay improve it with organic matter or grow in raised beds. Creating ridges in the soil to plant the sets into is also a good way of increasing drainage. They require plenty of sun and a rich fertile soil but do not need nitrogen so applying a fertiliser specifically for onion crops at the time of planting is advised. Each set should be 4 inches apart and each row should be 9 inches apart.
Varieties to Try
Onion Shakespeare is British-bred, brown-skinned variety that produces high yields of good-sized bulbs and shows exceptional bolt resistance when planted in Autumn. The excellent skin formation means it shows good storage potential well into the winter months.
Shallot ‘Yellow Moon’ is round with an attractive yellow colour. Although an early maturing variety it has high resistance to bolting and produces a very healthy, uniform crop with excellent skin quality and storage potential.
Garlic Provence Wight is a vigorous, white softneck garlic that produces really large bulbs. This French variety grows well in the UK and produces fat, juicy cloves that have flavour. Once lifted, they can keep until January. Also try the Marshalls exclusive Garlic Red Duke which is proving very popular due to its great taste.
Harvest and Storage
If all goes to plan, you’ll be harvesting your crop in June. However if we have a winter like we did last year you could expect a harvest even earlier in May. Harvest you crops as soon as their leaves begin to turn yellow and die back. Don’t force this by bending them yourselves, let it happen naturally because onions, shallots and garlic take up all the goodness from their leaves and store it in their bulbs resulting in a tastier crop.
Once harvested dry the bulbs by laying them in a warm, dry spot for a few weeks. If the weather is a bit wet, hang them in the greenhouse to dry out. Wait until the foliage is completely dry before storing in a dark, cool, dry place. Onions nets are perfect for this, but if you don’t have nets you can hang them or layers in boxes. Depending on variety they should store between 3-6 months. Check them regularly for any problems.
- If your soil is heavy and prone to water-logging avoid planting in the ground, instead grow in raised beds or even containers. This will help improve drainage and protect your crop from winter wet.
- It’s beneficial to use a fleece or polythene tunnel to protect you crop from extreme weather. This might not be necessary during the warmer period, however as the weather turns colder and wetter this added protection will be an advantage.
- If you’ve just lifted your last onion crop don’t re-plant with onions, shallots and garlic. Giving the ground a rest will help reduce the risk of diseases such as onion rots. Find another spot in your garden that hasn’t previously had Allium crops growing.
- When you’re ready to lift your crop, do it on dry day so that your bulbs stay dry and allow plenty of airflow around the bulbs to reduce the risk of disease. You can gauge how they are doing by how dry their leaves are.
Question ‘Are Welsh onions and potato onions the same thing?’ Moira Haigh
Answer: Welsh onions are Allium fistulosum but are commonly called spring onions. Although spring onion is a general term it includes many different species of alliums including Allium cepa. There are many varieties of Welsh onion, some look like the common spring onion whereas others look like chives or even leeks.
Potato onions, like regular onions, are Allium cepa but are placed in the aggregatum group, the same group which shallots belong to. Although potato onions are slightly larger than shallots, similarities can be seen between the two. Both shallots and potato onions, as well as other onions in this group, are also called multiplier onions because they form multiple onions from one mother bulb.