Tired of getting golf ball sized onions from your backyard garden? I’ll walk you through the trick organic farmer’s market growers are using to get big, sweet, softball sized (and larger) onions that are bursting with flavor! Whether starting with purchased onion sets or a packet of seeds, here is how to grow big onions:
How to Grow Big Onions
Onions are heavy feeders. That does not mean you need to spend a fortune buying fertilizers or soil amendments for them. (That would defeat the purpose of saving money by growing them yourself!) Here is what I am doing to get MASSIVE onions from a single strip of a backyard garden bed.
Short Day or Long Day?
Before you grow onions, you need to know whether you need short day, intermediate or long day onions. Where I’m at in Magnolia, Texas we absolutely have to grow short day onions. You won’t get a bulb to form if this is wrong. It is easy to buy the wrong seed online so order carefully. Your local nurseries and feed stores will typically have the correct onion starts for sale but the big box home improvement stores may be selling you the wrong thing! (This happens more often than you think and could be the reason why your onions haven’t worked out.)
Full Sun Required
You can’t skimp on the sunshine. Onions need a minimum of 10 hours (short day) to 14+ hours (long day) of sunlight to bulb. You will need to dedicate a strip of the sunniest spot in your garden to them. Luckily they are great companion plants to tomatoes, peppers, strawberries, carrots and lettuce so they will play nice with other sun-loving veggies. (Don’t plant them near beans, peas or asparagus because onions will stunt their growth.)
28 Degrees and Higher
Onions can handle temps 28 degrees and above. Be sure you are planting them as early as you can. In my area (zone 9a) I sow onion seed in October or plant starts the week before Thanksgiving in November because our winters are mild. If we are expecting a bad freeze, the onions will need a light cover and maybe a string of incandescent Christmas lights to keep them warm. The onions grow slowly all winter then bulb up and become huge shortly before the tops flop over and we begin to harvest in late April through mid-May.
Foliar Feeding for Massive Sized Bulbs
This is the secret to HUGE onions. I grow mine in raised garden beds topped with compost once yearly and NO other special soil amendments. Foliar feeding is all my onions get and it is all I’ve needed for gargantuan results.
my Foliar Feed recipe for absolutely explosive plant growth:
In a 2 to 2.5 gallon watering can (I use Behrens) combine 1 Tablespoon Trident’s Pride Fish Foliar Feed, 1 Tablespoon Organic Liquid Kelp and 1 teaspoon Cal-Mag. Exact measurements are not needed – just eyeball it as your pour it into the bottom of an empty watering can then fill with water to mix the solutions. Use this as a foliar feed by deliberately watering the leaves of your plants in the morning. Plants will absorb the nutrients within 15 minutes and an improvement in growth can be seen in 24-48 hours. It is truly an incredible combination! Works beautifully on all vegetable plants as well as onions, herbs, flowers, flowering shrubs and vines.
If you would like to qualify as 100% certified organic, opt for this organic Cal-Mag product. (Affiliate links.)
How to Foliar Feed Onions
Simply water the onion tops generously with the mixture every 72 hours or twice per week throughout the growing season. This is a quick splash where each plant gets perhaps two to three seconds of a shower from the watering can. The onion will absorb the nutrients through its tubular leaves within about 15 minutes. The foliar feed also nourishes the microbial life in the soil which contributes to strong plant growth in the garden.
That’s It!
Planting the correct onion variety in full sun at the right time of year and foliar feeding twice weekly is all I do to get large, juicy bulbs that look beautiful and store well when cured. I hope this has helped you learn how to grow big onions for yourself this year!
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