Home > Growing Vegetables > Growing Onions and Shallots in a Greenhouse

Growing Onions and Shallots in a Greenhouse

By: Rachel Newcombe - Updated: 26 Sep 2012 | comments*Discuss
 
Onions Shallot Grow Growing Greenhouse

Onions and shallots are among the most versatile forms of vegetables to grow at home. If you’re thinking of having a go at growing your own produce, then here are some tips and advice on growing onions and shallots in a greenhouse.

How To Grow Onions and Shallots

Both onions and shallots can be grown from either seed or sets. One of the easiest ways, and especially so for new greenhouse growers, is to begin by growing them from sets. Onion sets are beneficial as they do well in all conditions, even cold greenhouses, and are more resilient against pests and diseases.

To the uninitiated, an onion or shallot set is basically a mini bulb – a bit like a small onion or shallot. The fat end is put down into the soil and the tip remains just above the top of the soil. A variety of onions and shallots are available to purchase as sets and, although they’re slightly more expensive to buy than seed, they’re definitely better to start off with.

Onion sets are best planted from mid-March to mid-April and should be planted in rows, with about 8 inches between each row. Shallot sets are best planted from mid-February to mid-March and should be similarly placed.

If you decide to give onion or shallot seed a go, then onion seed should be sown from late February to early April, and shallot seed from March to April. Seeds should be sown in rows in your greenhouse, either in raised beds or in trays, with spaces of approximately 8in between each row. Each seed should produce a single onion or shallot and, as the seedlings grow you can thin them out.

Caring For Onions and Shallots

Once your onions and shallots are planted in your greenhouse, they’ll need to be watered regularly, especially if the weather is dry. If you spot any flower spikes growing, then remove these as soon as possible, as you don’t want flowers growing.

It’s best to stop watering the plants when the onions or shallots have swollen up in size. At this point, it’s also advisable to brush back any soil surrounding the top of the them, so that the bulb can get the benefit of extra sunlight.

If you’re not averse to using fertiliser, a general purpose fertiliser will help ensure that all the essential nutrients are present. Some gardeners suggest that a low potash fertiliser is good if you’d prefer to produce smaller and tastier onions.

When they’re grown outside in the garden, one of the biggest hazards is that birds will grab hold of the tip of the onion or shallot and pull them out of the ground, but thankfully when they are grown inside a greenhouse, you shouldn’t have this problem.

When To Harvest Onions and Shallots

The best way of knowing when the time is right to start harvesting your home grown onions and shallots is when you notice that the outer foliage is beginning to turn yellow or when it begins to droop over. This often happens from about July, especially for shallots.

Once harvested, the produce can be dried, then stored or used. If kept in a cool dark place, they can store well for up to 12 months.

You might also like...
Share Your Story, Join the Discussion or Seek Advice..
Why not be the first to leave a comment for discussion, ask for advice or share your story...

If you'd like to ask a question one of our experts (workload permitting) or a helpful reader hopefully can help you... We also love comments and interesting stories

Title:
(never shown)
Firstname:
(never shown)
Surname:
(never shown)
Email:
(never shown)
Nickname:
(shown)
Comment:
Validate:
Enter word:
Topics
Latest Comments
  • BabyGirl
    Re: Designing a Greenhouse for Disabled Access
    When I was eleven I started experiencing severe pain in my lower back. Doc said it had something to do with my…
    23 November 2018
  • GreenhouseGrowing
    Re: Growing Climbers in Your Greenhouse
    scramble - Your Question:I am seeking the same information as Squirrel: flowering climber for greenhouse that gets v hot…
    4 April 2018
  • scramble
    Re: Growing Climbers in Your Greenhouse
    I am seeking the same information as Squirrel: flowering climber for greenhouse that gets v hot in summer and cold in…
    2 April 2018
  • Squirrel
    Re: Growing Climbers in Your Greenhouse
    Dear ???? I have a sunny greenhouse on the 4 floor and wish to grow flowering creepers and plants.It gets very hot in…
    20 March 2018
  • zizi
    Re: Growing Flowers in Your Greenhouse
    l cant imagine world without flowers and plants.My major is agriculture engineering .I need some informstion about develop…
    11 March 2018
  • GreenhouseGrowing
    Re: Greenhouse Vegetables
    Jim - Your Question:I have tried to grow potatoes in my greenhouse for Christmas which appeared to be doing very well. However al I cropped…
    6 March 2018
  • Jim
    Re: Greenhouse Vegetables
    I have tried to grow potatoes in my greenhouse for Christmas which appeared to be doing very well . However al I cropped was lots of very…
    4 March 2018
  • GreenhouseGrowing
    Re: Starting With Orchids
    Pop - Your Question:It is now October is it too late to grow chrisanthimum's in my greenhouse. If not where can I get some cuttings
    10 October 2017
  • Pop
    Re: Starting With Orchids
    It is now October is it too late to grow chrisanthimum's in my greenhouse. If not where can I get some cuttings
    7 October 2017
  • Jay
    Re: Common Greenhouse Problems
    I've just brought an old house with a greenhouse in the garden. It's not been touched for ages I turned it the other day and was…
    19 July 2017