Growing Onions

Growing onions is an excellent pastime but care needs exercising as many producers sell them around £3.50 per 20Kg bag and if price is your only consideration it may put you off and if you are short of growing space then simply buy them in from a reputable supplier as many grow organically now.
If food security is of more concern and you either have the space to grow them in the ground, if have large containers you can grow them as they grow well in containers and your next choice is to grow by the book or not? Growing by the book yields excellent and consistent results but this involves more work and if you have a full gardening schedule you may not need the additional work so I will give my experiences and ignore the book.

Onions come as seeds or sets and while seeds are self-explanatory the sets are basically small immature bulbs you plant and fatten up just like meat such as cattle, pigs, or sheep and you harvest when they are ripe or their tops begin to drop and die off. Both have benefits and negatives and while sets are only generally available twice a year from garden suppliers or online dealers many growing from seed can grow many more plants for less money and either fill a container with their overspill or use them to barter with.

Prepare your ground by using well rotted compost and a little manure, the soil/growing medium needs to be free draining and I suggest compressed poultry muck such as chicken pellets and don’t overdo the manure at this stage or you will end up with lots of green tops and tiny or no bulbs

Growing from seed – Place your growing medium into seed trays with the individual cells and plant 5/6 seeds in an individual cell and stand the seed tray in water to wet the compost through and place in your greenhouse heated to around 10°-16°C and keep the seeds moist until germination. Plant seeds in late autumn to mid spring and be prepared to thin them out and any bald patches in your bed or containers to maximise your yield.
Growing outside is also from late winter to mid spring and you watch the weather as they are best planted and grown when the soil is not waterlogged and the soil temperature rises slightly, you use plenty of seeds and make a circle around the outside of your container if it is round about 3” (75mm) from the edge and put your seed in this trench which should be around ½” (12mm) deep and cover with compost; make another circle about 3” (75mm) inside your outer circle and repeat and continue until you fill your container right to the middle of the container and it is filled. Why do we fill the containers with seeds? Because you can always thin onions out by removing selected plants and planting them in a pot to keep for filling in bald spots in other containers or the ground.
If you plant seeds directly into the ground they also need rows ½” deep with the rows 8” (200mm) apart.

Growing Sets are especially beneficial for ease of use and while they are more expensive than seeds they are less work as they are generally in paper containers or cells with nutrients built into the container so just the right quantity is available for this stage of growth which is beneficial for beginners.

Make sure you get the right varieties to grow at the right time of year as many people grow the wrong onion types at the wrong time of year and they simply die and people lost the costs and their time for silly mistakes.

Why do you crowd containers and beds? Contrary to popular belief and the books onions hate competition and while they tolerate competition from other onions they hate competition from weeds and crowding leaves little to no room for weeds to grow and no weeds means no competition for the plants as weeds sap the nutrients which kills the plants and no or very few weeds means little to no weeding.

How do you thin them out? Basically you begin by thinning out until you have 2” (50mm) between plants and as they grow you thin out again and go to 4” (100mm) between plants as this gives the bulb the space they need to develop and grow to a reasonable size.
What do you do with the thinning’s? You eat them as they normally develop to about the size of spring onion and you eat spring onions and you can have them raw or cooked and you can cut them up for cooking and they make excellent soup and onion sauces. For your second thinning the bulbs will be bigger and much like the spring onions with the golf ball sized bulbs.

Seed grown onions tend to “bolt” and this means they grow flowers and you need to avoid this as all the plants energy goes into the flowers and not the bulbs and if yours are showing the signs of bolting you immediately nip the flower stem off.
You may want a quantity if onions to bolt as the flowers contain the seeds and a few flowers contain a lot of onion seeds and if you seed your own you will be in the same position you are with tomatoes and peppers in that you may never buy onion seeds again.

Harvest summer to late autumn and if you have mature onions they can be stored somewhere cool such as a shed or garage and the slow growing varieties tend to last longer than the faster growing varieties so be careful if you intend storing a lot of onions. Thee are several ways to store onions and the cardinal rules are that they must never touch each other and they can be placed on upturned trays with holes in the bottom or hung but you need to prepare them first. When you pick your onions place them outside in the sun, or in a warm greenhouse for 2-4 days or until they crisp up and you can put then onto the bottom of your trays; OR

You can hang then on strong gardening twine and once the twine is hung you tie the top of your onion close to the bulb, to your twine and then another below it so it isn’t touching and add more until your string is full, OR

One method is to use ladies used tights and cut the legs off, put your first onion into the bottom and tie a knot above it and add a second onion and tie a knot above this and continue until the leg is full and hang it somewhere cool.

You can grow 2 or more varieties of onions and many people do this as they like a mix of brown and red onions and growing them together is always beneficial.