How to Grow Green Onions from Kitchen Scraps

Grab a bunch of store-bought green onions and cut the stems off with a clean knife or scissors. Leave at least an inch of the wide white base, the part that still has those little root tips on it. That base is the piece that regrows.

The more of the white end you leave on, the faster and more reliably it comes back. The catch is that the crunchy white part is the tastiest bit to eat, so it's a bit of a trade-off. If you want a head start, err on the side of leaving a little extra.

Fill a container with regular tap water and stand the cut root ends upright inside. The one rule that matters here is keeping the green tops above the water. If the tops sit submerged for any length of time they'll rot, since green onions are still land plants at heart.

A skinny jar or glass makes this easy. Add only about half an inch of water, just enough to cover the roots, and let the tips lean against the rim to stay upright. Set the jar somewhere with light and leave it be.

Within a day you'll see the inner rings of the onion start to elongate and push up out of the cut top. That's the plant waking up and it's exactly what you want to see. It happens fast at room temperature.

Over the next few days those inner shoots turn into new green leaves growing right out of the middle. Change the water every couple of days to keep it fresh, because onions sitting in still water can get a little funky. Clean water keeps the whole thing healthy while it roots.

Within about a week you'll spot fresh white roots forming at the base. New white roots are the sign of success with any cutting, and green onions are no different. Some bunches keep the little root nubs from the store and get a head start, but even if yours don't, new roots form on their own.

Once those roots appear the shoots really take off, growing as much as a third to half an inch a day. You can even snip the greens now and they'll keep regrowing right in the water for a couple more harvests. They're that eager.

Water alone will only take you so far. To keep the onions going long term they need soil, so grab a pot and any decent commercial potting mix. You want it light and airy, high in organic matter, and able to hold moisture while still draining freely.

Fill the pot all the way to the top and pack it in snug. Almost any size works, since spacing isn't fussy with green onions, but pick something at least four inches deep with drainage holes. Poke shallow holes for the shoots once it's filled.

Set each rooted shoot into a hole in the soil, then pack the mix around it so it stands on its own. Keep it shallow. The spot where the roots meet the stem, the root collar, is quite low on a green onion, and that's roughly where your soil line should sit.

Don't bury the shoots deep to hold them up. Instead plant them at the natural depth and firm the soil around the base for support. It's straightforward planting, and the roots you grew in the water will do the rest of the anchoring.

Right after planting, don't pour water on top or you'll wash the loose soil and the new shoots around. Water from below instead. Set the pot in a couple inches of water and let it soak overnight. The soil wicks up exactly what it needs and nothing more.

After that first soak they're easy. Water the soil about once a week, give them full sun, and harvest the greens whenever you want. Planted in soil this way, your regrown onions keep producing for months, so you may never buy a bunch again.