“Set”ting Up For Success: Planting Onion Sets

“Set”ting Up For Success: Planting Onion Sets By Marissa

Growing onions in Florida is actually pretty easy. You don’t even have to do much to have a successful crop! In my opinion, growing onions so far down South is all about the preparation and planting. Once that’s all done, you should be all “set!” The growing part is pretty easy. Of course, there’s a little maintenance, but it’s simple. Since onions scare away most pests, your maintenance mostly comes in the form of a little bit of weeding and fertilizing.

Let’s Get Set!

An onion used for planting is called a “set.” It looks like a tiny onion, and it may have a little sprout growing out of the top when you get it. The sprout lets me know the set is in good condition, like a little green flag. Shell’s Feed & Garden Supply carries onion sets for White, Yellow, and Purple onions, and Fall is an excellent time to get some into our gardens. Here’s a picture of Mr. Shell, owner of our store, showing off our onion set cart – with multiple onion types to choose from. You pick!

Quick Note: Which End Is Up?

This is an onion set. The sprout will come from the pointy end at the top, and the roots are at the bottom of the round bulb. You can see a touch of sprout poking out at the top and little roots that almost look like hairs already established at the bottom. They might look all dried out but they still function perfectly. The whole set is really hardy, actually. Onions are able to be stored as a dormant bulb for quite a long time, which is how onion sets survive to produce onions for the next season.

One Set, Two Results

You can grow onions for their greens, also known as onion tops or green onions, which are used in cooking and as garnish in many dishes. The greens usually have a peppery/garlicky flavor on top of the onion flavor, which makes them excellent seasoning when they’re fresh (it cuts down on the need for salt and pepper on your food – great if you have to decrease your salt intake or if pepper doesn’t agree with you, or even if you just like their taste!). You can also, of course, grow them as bulbs, to make nice round, firm, fresh, hefty onions at harvest time. There’s something so satisfying about seeing a patch of bulb onions growing in a raised bed or in a long row, they really are magnificent produce! If you’re looking to be using bulbs, you’ll want to leave the greens alone. So if you want to take advantage of the greens and bulbs, I would recommend that you plant two batches. How do you make identical sets grow into two different things, you ask? It’s all in the planting. I’ll show you how below as I go through the proper soil prep for successful sets. Just a little finesse will get you there!

Best Onion Garden Location

Onions like Full Sun. In the Fall, as the days grow shorter and the sun shifts away from being directly overhead, you’ll need a place that dodges shadows and maximizes the light during the day. Don’t forget that some of your neighboring garden plants might grow to shade your onions, so make sure when you make your garden plan that you consider the height and direction of the neighboring crops once they’re grown!

Soil Prep for Onions

To grow good onions, you’ll also need loamy, well-draining soil as well with a neutral pH and a relatively high nitrogen content. I like to grow onions in the same spot where I grew beans and peas in the Spring because beans and peas are nitrogen-fixers – they naturally add nitrogen to the soil all season, making it ready for other hungry crops. If you don’t have a garden bed that just had all the spent bean plants pulled, that’s ok. You can work in some aged manure from cows, horses, rabbits, or poultry (or compost from your compost bin… don’t let those vegetable nutrients go to waste!) into the soil to give your onions a good nutritious base to begin growing. Side note: If you aren’t currently composting your vegetable and paper waste, maybe consider using compost worms! Here’s an article about building a vermicomposting bin.

If you don’t have that, well, Shell’s Organic 3-3-3 fertilizer is absolutely amazing for planting time, as well as for growing. Mix into the soil at planting, then as the onions get established, side dress as directed. If you want a fertilizer that is a little bit stronger, Shell’s also makes a 6-6-6 that is great! Compacted soil (like sand) will yield stunted plants and you won’t get the nice bulbing effect we look for in a good onion. You will need to loosen the soil enough that the roots will be able to penetrate it, and if it is a really sandy soil, you’ll need to mix in garden soil with organic material in it (again, compost is good for this). Use a tiller, hoe or hand “claw” tool to mix in anything applied to your garden bed to ensure it’s mixed properly and fully, then rake it level.

Planting Strategies – 3 for 1

As mentioned briefly above, there’s two ways to use your onions, and there’s 3 ways to plant them. Choose what works best for your space! To get green onions from your sets – plant the set about a ½” inch in the ground, making sure the top half to two-thirds is above the dirt. Sets are pretty small, so this might be a little tricky. Plant them relatively close together to help keep them from bulbing. If you’re planting in rows, keep them 2-3” apart in the row, and the rows 10-12” apart. Side note: Green onions and scallions are slightly different. Many people call them the same thing. They are in the same family, but scallions don’t really bulb at the bottom, and are a different species. It doesn’t matter much in my opinion, they taste relatively the same!!! To get bulbing onions from your sets – to make the sets turn into bulbs, plant them about ¼” deep (really shallow!), 4” apart. Allow them a few weeks to sprout and really get settled in. You want them to take root securely before you take the next step. After they are rooted and greens are sprouting and looking healthy, which is usually 3 weeks or so, use your fingers to gently move some of the dirt away from the base of the bulb, being careful not to uproot your onion. This triggers the plant to begin building the bulb, and usually works just fine. Some of them just may never bulb, and that’s ok, just use them for chopped green onions like you would use scallions or even chives. It’s the luck of the draw, so to speak. To get a mix of green onions and bulbs from your single planting – Another tactic is to plant sets close together, which is about 2” apart. As they begin to grow and mature, harvest scallion plants for eating by pulling them strategically to give the remaining onions space to grow bulbs in a process called “thinning”. Explained another way, if you have onions in rows 2 inches apart, pull every other onion to use as a scallion, then your remaining onions will be 4” apart and have room to bulb. This will ensure that you get green onions throughout the growing cycle of the bulbing onions.

Yes, you can grow onions in containers. I really like this third planting option if you are growing in containers, on a patio or balcony. It’s the perfect way to make the most of only a little space! This harvest pictured here is white onions grown on a patio – aren’t they lovely? The mixed-use planting of putting the sets close and then strategic harvesting of green onions to give space to the bulbs allows you to maximize your space and still have fresh onion ingredients to cook with for the longest time possible. Just be careful that you don’t plant so many that you couldn’t possibly eat them all! Or, I suppose you could just become that really generous, popular neighbor or coworker who gives away lots of yummy green onions and bulb onions (not a bad thing, really). So that’s what I have for planting and growing onion sets. Later in the season we’ll talk about harvest time and what to do! Thanks for reading. Marissa
Marissa – Writer for Shell’s Feed & Garden Supply

I’m an over-educated, passionate, gardening and pet enthusiast, and I have found the perfect job! My writing is based on my studies in Biology and Health, and my experiences from gardening with my family as a child. 

The great thing about gardening is that it is a life-long learning process. The many blunders and successes of my own gardening projects over the years have been invaluable to me.  The late, great, J.C. Raulston once said, “If you’re not killing plants, you’re not stretching yourself as a gardener.” Learn by doing, gain knowledge from the failures, but more importantly, relish the successes, (because they’re delicious!)  Thanks for reading!

Special thank you to Abby’s Farms, where the photo on the left was taken. Shell’s Feed & Garden Supply sponsors the chickens and chicken coops there. Visit their website here.  

3 responses to ““Set”ting Up For Success: Planting Onion Sets”

  1. Cam Karosis says:

    Marissa, this is such a great blog! I’ve always wondered how to properly plant onion and as I finish mapping out my new garden next year I’m going to use this for reference. Thanks so much! I’m looking forward to reading the other articles. 🙂

    • Marissa Byrum says:

      Hi Cam! Thanks so much for your comment, I really appreciate it! I try to provide helpful and useful content for Florida gardens, so I’m glad I succeeded on this one! I really enjoy writing these entries, thanks for reading! If you know of something you’re looking for information on, send me a note – I’d be happy to add topics to my lineup by request. Have a great day, and enjoy your garden planning!

  2. Cameron Karosis says:

    Marissa, this is awesome! I always wondered how to properly plant onions. Great blog you have here!

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