or Plant Start: Decisions, decisions
The gardener has the choice of three “beginnings” for their onion patch. Onions can be grown from seed, like so many other annuals. They can also be planted from sets, which look like tiny cured onion bulbs. They can also be grown from baby onion plants, which look just like small, stocky green onions.
Onions From Seed
- Advantages: cheap and lots of variety.
- Disadvantages: a little fussy and time consuming
Onion seed ages like Mickey Rourke. Which is to say, not very well. Start with current-year, fresh seed. For the most uniform crop of onions, you might want hybrid seed which will help ensure your onion plants bulb at the same time, and reach harvestable size in a fairly narrow window. This makes harvesting and curing more convenient. If you prefer to avoid hybrid seed, make the effort to buy from a seed house that’s doing active work in keeping their open-pollinated lines reliable and consistent.
When we start onion from seed, really we’re growing our own baby onion plants to transplant later.
Start onion seeds very early in the year – in the Maritime Northwest, January isn’t too early. Sow them lightly in a tray filled with potting mix. Something like a take-out food tray that’s about 3-inches deep is absolutely perfect, just poke some drainage holes in there. Make shallow, 1/2-inch deep furrows across your tray, spacing the furrows about 3-inches apart. Aim to sprinkle about 6 onion seeds per inch along the furrows your tray (you know, 6-ish…you’re not transplanting kidneys here), then cover with soil.
Water in your onion seeds gently, and nurture your seedlings under lights or in a greenhouse or protected area until the chive-like sprouts are large enough to transplant out to the garden. If you can get them to the thickness of a straw or pencil, that’s ideal. If the onion plants get too floppy and unmanageable, give the plants a haircut, cutting an inch or so off the leaves. (You can use these trimmings like chives.)
As soon as the weather has warmed enough that you start to see real growth from your spring bulbs – narcissus, tulips, etc. – you can transplant your baby onions out to the garden (see section on onion plant starts for transplant details).
Onions From Sets
- Advantages: easy
- Disadvantages: extremely limited variety, occasionally unreliable bulbing or storage qualities
Sets are a common sight in the nursery every spring. They look like tiny, cured onion bulbs, with the papery brown skin and everything. Typically you’ll see them corralled small, plastic mesh bags that allow for good airflow. They might be labelled, “red,” “yellow,” or “white” with no additional varietal information given.
Planting onion sets is as easy as it gets. Wait until your local nursery is selling them, take them home, and shove them root-side down and pointy-side up into damp earth until the pointy bit is just a bit below the soil level. Wait.
For best results, sort through your sets a bit as you plant. Try to plant mostly uniform, regular-size elongated sets. These are most likely to successfully form a nice, globe-shaped onion. Sometimes you’ll get big, oversize jumbo sets. Bigger isn’t always better – and this is one of those cases. Dramatically larger-than-average sets are more likely to bolt instead of sizing up.
Spacing your sets 4-inches apart or a bit more will allow them to grow into nice size bulbs. Plant 2-inches apart or even closer if you want to yank every-other-plant as they grow to use as green or spring onions.
Onions From Plant Starts
- Advantages: easy, reliable
- Disadvantages: expensive, somewhat limited variety
My favorite easy option for a bountiful onion patch is starting with onion plants. Onion plants look like trimmed up, thin green onions. They are the freshly dug onion plants, just like what you would grow from same-year seed, if you had the time and inclination to do so.
Dried slightly to send the plants into dormancy but still very much alive, typically they are sold in bundles of 50 or so onion plants, all of the same variety. Prices generally range from ar