Alrighty, everyone, it's finally time to talk about my most favorite crop! Onions are classified primarily by daylight hours: long, intermediate, or short day. Here in Central Texas, we should exclusively use short-day onions, but you can still have some success with intermediate-day varieties.
This means that it is vital that you choose the suitable variety for the right climate. While most onions are biennial, there are also perennial onions. Both can be found in nurseries starting late October to plant out immediately.
Be aware that white onions are milder than yellow onions, which are milder than red onions. Also the name ‘sweet onions’ was not chosen for their raw, sweet edge, but because they have more latent sugars that come out during slow cooking preparations and caramelization, making them more of a specialty use onion.
Now before getting into the growing process, what kind of onion will we need to use: transplants (from seeds), or sets?
Onion seeds should not be directly sowed into your garden, but instead started comfortably indoors to be transplanted after separating clumps. I start seeds in August for November planting.
This is almost always done on the home scale and it would be rare to see onion transplants at the nurseries. Instead you will find onion sets.
Onion sets are onions grown very small and stored for selling the following year. The biggest trade off is that the onion set’s priority is now seed production as opposed to a fresh transplant which is focused on bulb production.
Success between transplants over sets will be fairly negligible though with the right applied knowledge.
Focus on planting the smaller sets over larger sets. This may seem counter-intuitive, but the larger sets will go to flower sooner than smaller ones. Each set will try to bulb itself out to a satisfactory size then go straight to flower when given the first chance.
This diverts energy away from bulb growth and if that onion does set a flower then its shelf life will be dramatically reduced (lasting less than three months before spoiling).
This serves as a great reminder that a plant only has so much energy to assign to various processes and with physical intervention we can guide and focus the plants towards our goals.
_____________________________________________
Onion cultivation guide
1. Start by loosening your soil and removing any weeds. Onions need high organic matter, so apply fresh (preferably manure-based) compost with a slow-release fertilizer like my personal favorite, Microlife 8-4-6.
2. Plant three inches off center. Each onion needs to have three inches of room to grow on every side, for a total diameter of six inches per onion, not overcrowding or wasting space. Do not plant too deeply… just the root and any white stock is fine.
3. Water frequently at the beginning. As roots develop, start to space out the waterings while still watering deeply. This will encourage roots to travel into the subsoil to access water stores. I always check my soil with the finger test before ever turning on the hose. Simply poke your finger in the soil to the second knuckle. If the soil is bone dry, water; if not, come back later.
4. Prune! Onions have a neck, and if it breaks, the growth will immediately end regardless of size. Give your onions occasional little haircuts, making them bushier and less top-heavy. This assures a heavy wind won't cut their growth short, and you get the bonus of a few rounds of scallions before bulb harvest.
5. Harvesting and curing come as we see the neck of the onion bent over. This will happen about 125 days after planting in late spring. Leave the onions to dry in the ground for two weeks, then either braid them or lay them on a table without touching one another for 3 - 4 weeks in a shady, cool outdoor space that won't get rained on.
6. After all that, they are ready to come inside and enrich your meals for the next 6-12 months (if they last that long, I know mine don’t!).
(Barton Springs Nursery expects onion sets to arrive in early November. At the Natural Gardener, it'll be January.)
_______________________________________________
Some relatives of onions:
Shallots are perfect for those with more limited space; you can pack many more shallots into the same space as you would onions, and they will be ready 50 days earlier on average compared to onions.
Leeks will want even more fertilizer and organic matter in your soil than most other types of onions. Make sure to plant deeply (over eight inches) because the best part of the leek needs to grow devoid of light. They will also want liquid fertilizer, ideally every 2-3 weeks.
Perennial onions are likely to be smaller and more tedious to use in the kitchen, but the flip side is having year-round access to fresh onion bulbs, bulbets, or scallions/chives. Look out for transplants for walking onions, welsh onions, or potato onions to always have a year-round source of deliciousness. Happy growing everyone! ❦
