Why You Should Plant Your Windowsill Spring Onions Instead of Leaving Them in Water

Last summer, many of us learned to save our green onion stems, pop them in a glass of water, and watch as bright green shoots appeared before our eyes. This summer, we should definitely do it again — but this time, actually plant the sprouts in soil.

Windowsill spring onions are a beautiful thing, but they have a significant downside: They don’t always taste that great, especially after a couple of sprout cycles. Plain water is all they need to start sprouting, but it doesn’t offer our allium buddies any of the nutrients they need to grow properly. This comes through in the regrown scallions. Personally, I’ve noticed that scallions grown in just water always turn out weirdly watery and slimy on the inside, with noticeably less flavour than I’d get from a store-bought bunch.

The solution is to plant them in potting soil like the plants they are, and pretty much any store-bought soil will work great. As for pots, a long, narrow, windowsill-type planter is the most natural choice, but you can use anything with drainage holes. Once your scallions have sprouted, plant them 1/2 to one-inch deep in the potting soil and put the pot somewhere that gets plenty of bright, direct light. (A windowsill or patio is perfect.) Spring onions thrive in moist, slightly acidic soil — think a pH of six or slightly below — so frequent waterings and the occasional splash of flat LaCroix or diluted black coffee will keep them happy.

Don’t worry if you can’t nail every condition, though. Spring onions aren’t picky; even if your apartment doesn’t get the best light, you’ll still reap the rewards all summer long. Last summer, we planted ours on a small shared patio that gets a ton of direct afternoon sun and, if I’m being honest, mostly ignored them. They still went absolutely bonkers — some grew to almost two feet long in just a month or two, and I had to start giving them away. Most importantly, my homegrown spring onions tasted incredible and had a perfectly crisp texture. I can’t wait to plant more and eat them all summer long.