Grow at Home: Spring Onions or Scallions•
Posted on 5 October 2020
The world wide popularity of Spring onions is obvious from the number of names they go by including: Scallions, green onions, spring onions, salad onions, shallots (Australia), eschallots, Japanese or Welsh bunching onions (these grow in clumps rather than singly), green onions (China) and Egyptian or tree onions. green shallots, onion sticks, syboes or jibbons (the one I grew up with) They have to be one of the most versatile members of the onion family. Use them in your salads, as a garnish to soups and sandwiches or sizzle them in stir-fries.
Spring onions do not have very deep roots so can be sown either in the ground or in a Raised Bed or Shallow Vegetable Planter. So they might be a nice thing to have growing in a sheltered spot just outside your back door.
Spring/ Summer sowing
Sow thinly 1cm (½in) deep from March to September in rows 10cm (4in) apart. It is best to sow a few seeds every 2 weeks to give you a regular summer harvest. Thin until they are about 2.5cm (1in) apart and use thinnings to add flavour to your meals. Water if the soil or weather is dry. Also, mulch to maintain soil moisture and keep the soil weed free so your seedlings don't have to compete. They will take around 8 weeks to grow to maturity.
Winter hardy varieties are available. You can sow these from August to October. Ones planted later in the season may take longer than 8 weeks to mature depending on the temperature. If you are impatient to eat them then keep them warmer by using a greenhouse, Bell Cloche, Easy-Tunnel or a Grower Frame. Wherever you grow them, you can enjoy some young shoots during winter and leave the remainder to mature. The main crop will overwinter nicely and be ready in Spring.
Pests & Diseases
Onion white rot:
This is a soil-borne fungus that rots the roots and bulb under the soil. The first you will know of it is yellowing leaves and wilting of the foliage above ground. A white fluffy fungus appears on the bulb and it later becomes covered in small, round black structures. There is no chemical cure for onion white rot once it is in the soil. It lasts for years and can't be eradicated. However it will remain dormant in the soil unless a member of the onion family is planted there so the only solution is not to grow onions there again. Clear all the plants as soon as you spot the disease. Dispose of them by burning or putting in your household waste. Do not compost! Also clean all tools used as it is transported in contaminated soil. Be careful to clean footwear too so you don't contaminate other areas of the garden or worse still a neighbours plot.
Onion downy mildew:
This is a fungal disease that damages foliage and bulbs, resulting in poor yields. It is a particular associated with damp conditions. If you spot it, remove any infected leaves. Thin and weed regularly to space plants correctly so that air can circulate around them and they have plenty of light. Also, avoid overhead watering if possible.
Harvesting Spring Onions
Pull the spring onions when the plants are, around 15cm (6in) tall and the bulb is no more than 1-2.5cm (½-1in) across. You might want to leave a few to go to seed as a treat for the bees and to get free seeds for next year. Collect the seeds by snipping off the flower head and storing in a paper bag for a couple of weeks until dried. Then shake the seed head into the bag and store in a cool dark place until you are ready to sow again.
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