Indoor basil dies for three predictable reasons: it was overcrowded from the store, it isn't getting anywhere near enough light, and it gets flower buds nobody pinches. Fix those and basil is a months-long crop, not a two-week garnish.
Nora Finch
A supermarket basil 'plant' is actually twenty or more seedlings crammed into one small pot - grown dense for shelf appeal and destined to strangle itself within weeks. The roots compete, the inner stems get no air, and the whole clump collapses on schedule no matter how well you treat it.
The rescue takes ten minutes: tip the clump out, gently tease the rootball apart into three or four smaller clumps (tearing some roots is fine; basil forgives), and pot each into its own container with fresh potting mix. Water well and expect a few days of drooping while they settle. Those divisions will each outgrow the original pot within a month.
Basil is a Mediterranean sun plant that wants six or more hours of direct light a day - the sunniest windowsill you own, ideally south-facing. The leggy, pale, stretched-out basil with huge gaps between leaves is light-starved basil; it is reaching, and it will never thicken in a dim kitchen corner.
If your best window genuinely cannot deliver, a small full-spectrum grow light solves it completely: positioned 15-30 centimeters above the plant for 12-14 hours a day (a cheap timer plug automates it), it grows better basil than a mediocre window. In summer, a pot outdoors or on a balcony beats everything indoors.
Basil likes consistently lightly-moist soil and hates both extremes: it wilts theatrically when dry (and usually recovers after a soak) but rots quietly when soggy. Check daily by finger - water when the top couple of centimeters dry out, thoroughly, in a pot that drains. In a warm sunny spot that can mean every day or two; that's normal, not a problem.
Water at the base rather than over the leaves - wet foliage in still indoor air invites fungal spots - and never leave the pot standing in a full saucer. Morning watering beats evening: the plant heads into its bright hours stocked, and any splashed moisture dries during the day.
The single biggest difference between a scraggly basil stick and a bush is pinching. Once a stem has three or four pairs of leaves, pinch or snip the top just above a leaf pair - the stem branches into two at that point. Do this to every growing tip every week or two and the plant compounds: one stem becomes two, two become four.
Harvest the same way - take whole stem tops above a leaf pair, not individual leaves plucked from the bottom (that route produces the bare stalk with a tuft). Take up to a third of the plant at once; it regrows within a couple of weeks. And pinch off any flower bud the moment you see it: flowering switches the plant from leaf production to seed production and turns the remaining leaves bitter.
Potted basil exhausts its soil within weeks of active growth: feed every two to four weeks with a half-strength balanced liquid fertilizer. Go easy - overfed basil grows lush but bland, since the aromatic oils concentrate in moderately-fed leaves. Keep it warm too: basil sulks below about 10°C and hates cold drafts, so pull pots back from freezing windowpanes in winter.
Even perfectly kept basil ages out after several months - it's naturally short-lived. The pros just never let that matter: snip 10cm cuttings from the best stems, root them in a glass of water on the sill (roots in about a week), and pot the next generation before the old plant declines. One supermarket pot, split and looped this way, is a permanent basil supply.
If the soil is dry, it's simple thirst - sunny-windowsill basil can need daily water. If the soil is moist and it still wilts in strong sun, it's transpiring faster than the roots can keep up; it should recover by evening. Wilting with soggy soil is the bad sign - that's root trouble.
You delay it rather than stop it: pinch every flower bud as soon as it appears and keep harvesting the tops regularly. Heavy, frequent pinching keeps the plant in leaf-production mode for months longer.
Yes, easily - seeds germinate in about a week in warm soil on a bright sill, and a pinch of seeds sown every month gives a continuous supply. Seed-grown plants are sturdier than rescued supermarket clumps; they just cost you a six-week head start.
Indoors it's usually fungus gnat larvae (soil stays too wet) or spider mites in dry air - check leaf undersides for specks and webbing. Rinse the foliage, let the soil surface dry out properly between waterings, and use sticky traps for the gnats.
