Growing onions in Southern California

Growing onions in Southern California

Timing is everything . . . when it comes to growing onions, too. If you sow the seed at the right time, you’re almost guaranteed a nice bulb to eat. Conversely, if you sow at the wrong time there’s no hope. So many times I’ve heard people say their onions didn’t grow well, and when I inquired further I always found out that it was a matter of bad timing. It’s not your fault. Look at the seed packet:

“Direct sow in mid-spring . . .”

As a general rule, disregard the directions about timing on seed packets. They’re usually written for the Midwest, the Pacific Northwest, the South, the East Coast, etc. They’re written for almost everyone but us in Southern California. We’re different.

Here in the middle of the fall season is onion-sowing time in Southern California. Checking my notes from some past years, I sowed good onion crops on October 12, on October 17, on October 23, and even as late as November 15 one year. Whenever I had sown earlier or later than that, my onion bulbs didn’t turned out as well. So, I’d estimate that mid-October through mid-November is the sweet spot for sowing onions in Southern California. A mnemonic might be to think of sowing onions near Halloween.

By the way, if you’re buying and transplanting seedlings instead of sowing onion seeds you can just do it a month or two after Halloween. For example, I’ve successfully planted onion seedlings from early December into January.


How onions grow

Why is it that these dates work well? What happens is that onions start growing during the mild fall weather — they look like little blades of grass at first (see the photo at the top) — and then they go through winter slowly getting big, spiky tops which look like punk-rock mohawks.

Come spring, just above the dirt, the bulbs form. They’re basically a bunch of fattened onion leaves that are, instead of green, a white or yellow or red color, depending on the variety.

Soon the green tops start dying off; they dry and become yellowish and kink at the top of the bulb and topple over.

Time for harvest.

That’s how the life of an onion plant is supposed to proceed. But if you sow onions at the wrong time — in the spring as seed packets often suggest, for example — they’ll grow just fine at first, yes, but they won’t make the big bulbs you’re hoping for, if they make bulbs at all. I know this from firsthand experience, unfortunately.



I’ve tried a lot of varieties over the years, but my favorites today are Yellow Granex and Gabriella. My wife and I both love the taste of these sweet, yellow onions, and they reliably grow well for me year after year. I get my seeds of Yellow Granex from Botanical Interests, and my seeds of Gabriella from High Mowing.

When I’ve bought onion seedlings at a nursery I’ve had mixed success, but usually results have been good. The reason I like growing my onions from seed nowadays is that I know exactly which variety I’m growing. Often, seedlings at a nursery are not labelled in detail. They just say something like, “White Onion.”

Can we grow “long-day” onions in Southern California? I’ll answer that with the title of a post I wrote a couple years back: “You sure can grow long-day onions in Southern California.”

When I say “onions” I mean bulb onions, by the way, not green onions, scallions, or chives. Those are related but different. They’ll never form a large bulb, no matter when you plant them or for how long they grow.



Onions can grow surprisingly close to one another. Just picture how big you want the bulbs to get and then space the plants accordingly, if you’re planting in a row.

Last year, however, I arranged some of my onions in clumps of three or four plants instead of in rows (notice that in the photos above?). I got the idea from Charles Dowding, and it worked great. As the bulbs formed, each plant migrated away from the others. The method used my garden bed space very efficiently, and it also meant that I had to spend less time lining up tiny single onion plants in a row during transplanting. I’ll be planting in clumps again this year, exclusively.


Harvesting and storing

I stop watering my onions in mid or late April. They’re not ready to harvest yet, but their bulbs are enlarging and there’s enough residual moisture in the soil for the plants to finish their growth. Come May, at harvest time, they’re easy to twist out of the dirt as the bulb and the dirt are both dry.

We ate our last onion last week (mid-October). Having harvested our first onions in May, that means we had enough from the garden and were able to store them well enough for five months of eating onions every day. Even if I grew more onions, we would still stop eating them around now. The challenge isn’t quantity, it’s storage quality. Without a specific storage facility where temperature and humidity and airflow are kept at ideal levels, as commercial farmers use, onions will only keep for so long.

My storage method is exceptionally simple:

Hang the onions on something in the garage; that’s so they have plenty of air circulating around them. They’ll mold and rot faster if there’s not airflow. I kept them in milk crates one year and they didn’t last long. And make sure they’re in a cool, shady area. Airflow, cool, and dry. Those are the characteristics of the environment you’re trying to create.

One last thing: sometimes, instead of the tops falling over, onion plants shoot up a flower stalk. It’s pretty, but it’s not good for the quality of the bulb. All’s not lost though. The bulb is still perfectly edible, only it will have a woody, hollow core. Eat bulbs that sent up a flower stalk before you eat the perfect bulbs, for the perfect bulbs store longer.

What to do in a Southern California garden in May

What to do in a Southern California garden in May

May can be spring, or May can be summer. Last year (2016) it was spring, with cloudy and showery weather, but this year so far it feels more like summer with dry breezes and lots of sun and not much May Gray yet — yet! The forecast is for it to turn back to spring for the upcoming second week of this month, with showers and cooler weather.

Cool weather is great planting weather. Take advantage, if you can.

Regardless, it’s already been plenty warm for subtropical plants to set fruit. Maybe your citrus and avocado trees are like mine: still blooming but also with pea-sized fruitlets. And maybe you planted some tomatoes in March that are already setting fruit. If May ends up being more warm like summer, we’ll even get to eat some by the end of the month.

But I chose the photo above to represent May because it’s the prettiest subtropical flower forming fruit this month in my yard. Passion fruit vines have everything beyond beauty going for them too: vibrant, evergreen foliage; vigorous growth to cover a fence or pergola; not messy when their fruit drops; tangy and tasty fruit; plus a fascinating etymology. Maybe you have a place to plant one — maybe next week?

Sometimes it feels like we live in paradise, friends. If you want to keep it going, here are some May opportunities in the yard:

Sow and plant

– Sow or plant these vegetables: tomatoes, peppers, beets, eggplant, beans, cucumber, corn, squash, melon, chard, basil

– Plant peppers and eggplant later in May if you want to be really smart about it; late May into early June is an ideal time to plant these heat lovers because if you plant earlier they’ll grow slowly and bugs can decimate them; however, if you plant later than mid-June you’re not going to get as much fruit as possible before it cools in the fall

vegetables seeds and seedlings in May

My diversified portfolio of seeds and seedlings on deck, to be planted in the ground from tomorrow through the end of May.

Harvest and eat

– Harvest wisely by doing it early in the morning for leaves of lettuce, chard, and kale; they are turgid at this hour — full of water and crunchy — and will taste best and keep fresh longest

– Stop watering onions and garlic that you planted last fall once their outer leaves start to yellow; they’ll continue to enlarge their bulbs on residual soil moisture; pick them to eat anytime, but wait until their tops are totally dead if you want to store them

– Eat these goodies (had you planted them): blueberries, strawberries, raspberries, blackberries, tomatoes (especially smaller-fruited types), potatoes, onion, garlic, broccoli (still a few final florets!), peas, lettuce, beets, carrots, peppers (if you overwintered a plant)


– Go hunting at night with a flashlight to see which bugs are eating your plants; in May, you might find earwigs on peppers, pill bugs on strawberries, june bugs on avocado leaves, slugs and snails on lettuce; pick them up and drown them in soapy water, collect them and feed them to chickens, throw them into your neighbor’s yard (unless you live next door to me), or squish them on sight

– Weed spotted spurge and purslane before they set seed; uproot and lay them on the ground upside down so they dessicate and decompose (but beware of purslane’s ability to root and regrow if it’s laid on moist soil)

– Note sun and shade patterns throughout the day; May through August patterns are about the same, in other words, you can grow a warm-season vegetable or a deciduous fruit tree in a spot that is sunny now but may be shady at other times of the year (north of a building, for example, like these pomegranates)

pomegranate north of building


You might also like to read:

You sure can grow long-day onions in Southern California

‘San Diego’ tomatoes, and supporting tomatoes

Chickens eat bugs in the garden

You sure can grow long-day onions in Southern California

You sure can grow long-day onions in Southern California

October begins onion planting time, and I just put in some Walla Walla seedlings. Next week I’m going to sow Ringmaster seeds. These are “long-day” varieties, meaning they are said to be best adapted to northern latitudes, places that have long summer days, places like Walla Walla, Washington. In other words, I’m planting the wrong types of onions, on purpose, for the second time.

Last year, in a moment of rebellion or in the spirit of scientific inquiry (I don’t remember which), I decided to deliberately flout expert advice and attempt to grow the long-day variety Ringmaster, and just the other day we cooked up our last giant Ringmaster bulb. They grew very well — perfectly, I’d even say. So this year I’m trying another round to see if it was a fluke.

I will also plant Texas Grano onions, which is a short-day variety and is the recommended type for Southern California. It has produced well for me too, for many years in a row now. Texas Grano is a sure bet; Ringmaster and Walla Walla are somewhat experimental.


UPDATE, July 2016:

Looks like it wasn’t a fluke. Both of the long-day varieties, Ringmaster and Walla Walla, produced excellent bulbs, once again. Their production was just as good as the short-day Texas Granos. The only difference between the long-day varieties and the Texas Granos was that the Texas Granos were ready for harvest earlier, in June, but the long-day varieties weren’t ready until July.

I’m now of the opinion that every variety of onion is worth trying here in Southern California, regardless of whether a seed company, nursery label, or book calls it short, medium, or long day.