Although onions can be planted in either the spring or fall, fall planted onions are a great way to enjoy an earlier and larger bulbed harvest from next year’s garden.
Fall onions grow in much the same fashion as a fall crop of garlic does.
The onions seed (or sets) are planted in the warm autumn soil, and quickly establish a strong root system before winter sets in.
As the cold chill of winter arrives, the crop goes dormant. Then, as the temperatures and soil warm again in early spring, the onions come back to life.
And because they have already established strong roots the previous fall, the onions are able to grow quickly.
We have always planted both spring and fall onion crops. And without a doubt, our fall crop always seem to bring a much larger and better tasting onion than our same-year planted onions.
Fall planted onions also mature earlier. In fact, some of our fall planted onions can usually be harvested at near full-size as early as the following June.
Here is a look at how to plant for success when it comes to fall onions.
How To Plant Fall Onions
Growing great onions, whether in the spring or fall, all starts with great soil.
Onions, grow best in loose, fertile, and well-drained soil.
And that means adding compost before planting is a BIG plus! Especially if your soil is hard or clay-like. See: How To Make Great Compost For A Great Garden
We like to add about an inch of compost to the bottom of each row before planting.
And if you live in an area with heavy clay or hard soil, add in a bit of sand as well to help loosen the soil for better growth.
When To Plant Fall Onions
A fall-planted crop of onions needs at least 4 to 6 weeks of warm temperatures to become established in the ground.
Here in the Ohio, we usually plant our fall onion sets during the middle portion of September. That gives plenty of time for growth before winter.
We prefer planting onion sets over seed, simply because they establish quickly, and are easier to plant.
If you are planting seed, they will need to go in the ground 3 to 4 weeks earlier than onion sets.
We usually plant a mix of white, yellow and red onions each fall to have a good variety the following year. Product Link : Red/Yellow/White Onion Sets
How To Plant
For our onion bulbs, we dig a trench in the soil two inches deep and a few inches wide. For this task, a mattock (or garden pick as it is sometimes called) is the perfect tool.
It breaks up the soil and makes a perfect 2″ wide trench every time! Product Link : Fiskars Garden Pick/ Mattock
We actually use it for nearly all of our trench planted crops like corn, beans, garlic and of course, onions.
Before planting, we fill the trench back in with about an inch to and an inch and a half of compost.
Next, we plant the bulbs with the point end up, setting them into the compost a bit. We finish by covering with soil.
We like to space our crop bulbs about every 4″ to 6″ to allow plenty of room for growth.
Once covered, we then mulch with a 1/2″ layer of straw (shredded leaves work well in the fall too) to keep out weeds and keep in moisture.
Long Term Care
Much like a crop of fall planted garlic, it is important to give your newly planted onions a thick layer of mulch before winter.
Once the onions have grown through the surface, add a few more inches of straw or shredded leaves on top. This helps blanket the crop from the deep freezing and thawing cycles winter brings.
Autumn usually provides adequate rain for an onion crop, but if you experience long dry periods, water to help the roots become established.
Here’s to planting a great fall crop of onions this year, and being rewarded with an earlier and tastier harvest next year. Happy Gardening! Jim & Mary
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