The Tricks To Growing Onions Successfully
Growing onions for cooking or fresh use are best started early indoors
to get a good jump on the season.
They can be sown directly into the garden but the crop will simply be a
There is a myth in the gardening world that home gardeners need to
purchase "sets" to get a good crop. Professional market gardeners
simply sow seed for their main crops.
A nice row of onions (and carrots)
The trick to sowing direct into the ground is to sow early. Seed that
is not in the ground by the first week of May will not normally mature
before frost. So, look for a late April sowing to get those onions up
and growing well from seed.
Sowing indoors is easily done. Take a flower pot, sprinkle onion seed
on it so the seed is approximately 1 quarter inch from each other,
cover very lightly with soil, water with warm water and give full
The seeds will sprout very quickly if they are not too warm
(this is a seed that I wouldn't put on a heating mat but just leave at
room temperature). Grow them on with half strength plant food and full
light until early May when the rapidly growing onions can be carefully
transplanted into the garden.
For Large Roots
If you want your roots to be really large or really early, (such as
specialty Spanish onions), then I'd buy sets and plant these in late
April as well. But for general use such as cooking, go with seeding or
Outdoor sowing usually puts the seeds one half to one inch apart (it
isn't rocket science so you don't have to measure – just be close) and
one quarter inch deep. Note that deep sowing will simply kill the seed.
Rows for growing onions should be approximately 12 to 18 inches apart
if you are using a thick seeding rate. You want to encourage air
circulation in the garden to reduce or eliminate fungal problems.
When the growing onions start to touch at this close spacing, thin out
and use the smaller tender onions in cooking or pickling. This leaves
the remaining onions adequate space to reach two to three inches in
Feeding For Success
This is a shallow rooted vegetable so feeding
early in the spring combined with a mid summer feeding of liquid fish emulsion or other liquid organic fertilizer will give you excellent results.
This is over
and above the normal application of compost in the spring. This shallow
root system also means that you have to be careful with irrigation; you
should not allow the growing onions to get too dry during the heat of
the summer or you'll set them back. Again, drip irrigation is ideal but
overhead will work fine.
Harvest your onions as you need them through the season. Harvest by
thinning the plants as they mature and grow into huge specimens. You'll
be able to store them much more efficiently if you "cure" them in the
garden before you bring them indoors.
About The Tops
There's a lot of advice about knocking over the tops of bulbs to make
the bulb grow larger. Generally I understand the reason you knock the
tops over is to prevent heart rot if there is heavy rain just before
you cure the bulbs. If there are no heavy rains forecast (and the bulb
will not be absorbing excessive amounts of water) there is little
reason to knock over the tops.
Curing Onions Before Storing
To cure the bulbs for storage, pull the bulbs out of the ground and
allow them to sit on top of the soil for 7 to 10 days to "cure". Avoid
leaving them to be exposed to frost. Leave the soil on the roots to dry
The neck will dry out during this time and you can
remove it just before storing the bulbs. You can also clean the soil
from the roots at the same time as the dried out necks are removed.
(necks are the long leaves that will wither down when pulled from the
soil -you'll understand when you see them) Do not cut into the green
growth of the bulb before storage.
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