Green onions, or scallions, are about the most forgiving thing you can grow: cool-tolerant, low-light, quick, and so undemanding you can regrow them from the root ends of a store-bought bunch. A fine place to start.
What it wants
Green onions ask for very little:
- Temperature, 55 to 75°F, and they shrug off cooler. Heat eventually pushes them to bolt, but they are patient.
- Light, a modest DLI of 12 to 17 mol/m²/day; they are not a high-light crop.
- Feeding, pH 6.0 to 6.5 (alliums like it a touch higher than the leafy crops) and EC 1.0 to 1.8 mS/cm.
- Humidity and air, ordinary airflow; they are not fussy, but soggy, still conditions invite rot.
- Roots, cool and oxygenated, and not waterlogged.
The arc
From seed, green onions are ready to pull in about six to eight weeks, and they are happy to be cut-and-come-again: snip the green tops and leave the white base, and they push new growth. Easier still, the root end of a store bunch will regrow in water or media, which makes them the classic first crop. A small succession keeps a steady supply.
What it fears
There is not much to fear, which is the point. The common stumbles are overwatering (alliums rot in soggy media) and, eventually, bolting to a flower stalk in heat or with age, after which the stem toughens. Thrips can find them, but green onions are among the most trouble-free crops on this site.
Getting it right
Sow them densely, keep them cool and modestly lit, and cut the tops as you need them. Try regrowing a grocery bunch alongside seed to see the difference. A small staggered sowing keeps the supply continuous, and because they ask so little, they are an ideal crop to learn your system on before moving to something fussier.
Tools for this crop
Frequently asked questions.
Can you regrow green onions?
Yes, and it is the easiest trick in indoor growing. Keep the white root ends of a store-bought bunch, stand them in water or pot them in media, and the green tops regrow within a couple of weeks. You can harvest the regrowth several times before the plants tire, which makes scallions a perfect first crop.
How long do green onions take to grow?
From seed, about six to eight weeks to a usable size, after which they are cut-and-come-again: snip the tops and leave the base and they keep producing. Regrowing from a store bunch is faster still, giving new green tops in a couple of weeks.
Are green onions easy to grow indoors?
They are among the easiest crops there is: cool-tolerant, low-light, quick, and forgiving of beginner mistakes. The main thing to avoid is overwatering, since alliums rot in soggy media. Their low demands make them an ideal crop to learn a new system on.