Water when the compost is dry — not when the calendar says so

Because the compost has dried past the point where it takes water back. It beads on the surface like rain on a waxed jacket, or runs out of the pot holes in a couple of seconds while the pot stays light. Either way, the middle of the rootball is still dry. If the pot gets heavier and the water appears slowly, that is not the problem — it went in.

When the compost is dry 2–3 cm down — not because it is a certain weekday. In a UK heatwave that can mean twice a day for a hanging basket, and every few days for a raised bed. An established border usually wants leaving alone except in a real drought. I cannot give you a universal timetable that survives a grey week.

Finger first, then look at the leaves. Wilt plus wet compost: stop — roots cannot breathe in soggy mix. Wilt plus dry, light compost: soak. Yellowing from the bottom on wet compost is the other overwatering tell. Midday flop that recovers by evening, with damp compost, is heat rather than thirst. Leaves alone will not tell you the difference.

Enough to wet all the roots and the compost around them. Fill to the rim, let it soak, repeat until the first drops appear slowly at the drainage holes, then stop. A torrent in two seconds with a light pot is run-through — the middle is still dry. A working starting volume is about a tenth of the pot: 1 litre for a 10-litre pot. Then empty the saucer within a few hours.

Morning. Plants use the water through the day, less of it evaporates, and foliage can dry before night. Evening is acceptable if you keep water off the leaves. Midday is wasteful because more evaporates — droplets do not act as burning lenses on ordinary leaves Egri 2010 — but a plant in genuine wilt should still be watered, even at noon.

Dry compost can shrink from the pot wall or shed water. Peat and bark-rich peat-free both do it; coir usually takes water back more easily. Water follows the channel down the side; the middle stays dust-dry. Water in stages, stand the pot in a tray, and firm the compost back. A wetting agent at 2.5–5 ml per litre only if it still runs straight through — Natural Wetting Agent if you need one, or the wetting agent FAQ.

Usually not. Water the stressed plant, not the whole border, and only in hard drought. New plantings are different: veg and new perennials want moisture to about 15 cm; trees and shrubs in their first years want moisture to 20–30 cm when the top few centimetres dry.

No. Aim at the compost or soil above the roots. Wet foliage overnight, especially under glass, invites fungal disease. The exception is a deliberate foliar feed, or a rinse of dusty leaves on a morning that will dry them quickly.

Rainwater in a butt is what I reach for first: softer than most UK mains, which peat-free compost and lime-hating plants prefer, and still there during a hosepipe ban. Do not use stored butt water on seedlings — damping-off (a fungal collapse of soft stems at compost level) is the risk. Grey water — washing-up or bath water without bleach or strong degreaser — can go on ornamentals the same day, not after it has sat overnight, and never on salads or anything you eat raw. During a Temporary Use Ban (TUB / hosepipe ban) a can from a butt is usually still allowed; hosepipes and sprinklers are not. Check your water company. Mains is fine; it is just the expensive option. RHS on stored water Ofwat restrictions

An overwatered plant often wilts with wet compost, yellows from the bottom, and may sit in a sour-smelling pot with a full saucer. Soft stems at compost level in seedlings is damping-off. The leaves look thirsty because roots starved of air cannot drink. Yellow leaves from overwatering are not a nitrogen shortage — do not feed until the compost has dried. If it has gone on long enough you get root rot: brown, mushy roots. Stop, drain, and only then decide whether it can recover — see how to save an overwatered plant.

An underwatered plant sits in a light pot. The finger comes out dusty. Leaves go dull, then limp, then crispy brown at the tips and margins. Flowers and fruit abort in a hot week. Compost pulled away from the pot wall is the same drought. Soak slowly until the pot is heavy. That is how to save an underwatered plant — one proper soak, then back to the finger test.

That is overwatering, not thirst. Saturated compost has no air, so roots cannot take up water even though it is sitting there. Stop. Empty the saucer, clear the drainage holes, and wait until the top 2–3 cm is dry. More water makes it worse. Midday flop that recovers by evening, with damp compost, is heat — not the same problem.

Only if the finger test says the compost is dry. Hanging baskets in a UK heatwave can want twice a day. A 10-litre pot is more often every day or two. An established border almost never wants a daily can. Watering once a week because it is Monday is how pots drown in a grey week and bake in a hot one.

No. A watering schedule is the calendar pretending to know the compost. If it is dry 2–3 cm down, water. If it is damp, wait. If it is wet, stop. That is when to water — by the compost, not by the day of the week.

Finger first. If the compost is dry, fill to the rim, let it soak, repeat until the first drops appear slowly at the holes, then stop. Empty the saucer within a few hours. Lift the pot: if it is no heavier, the water ran round the roots. Water in stages or stand it in a tray. That is how to water potted plants; a daily sip is not.

Tip it out of the pot. Healthy roots are firm and pale. Brown, mushy roots that smell of drains are rot. Cut the dead stuff back to firm tissue, knock off the sodden compost, and pot into something that drains. Do not water until the top 2–3 cm is dry, and do not feed it. A plant with no remaining white roots rarely comes back — take a cutting if there is still a living stem.

A cachepot (decorative outer pot with no holes) is a vase. Water the plant in its nursery pot, drain it properly, then drop it back in. Gravel in the bottom does not make drainage — it makes a perched water table (water sitting on the gravel above dry compost). Drill holes, or tip out standing water every time.

Most of the North West, including Stockport, is moderately to very hard. White crust on the compost is lime from the tap, not mould. Rainwater is kinder to peat-free mixes and to lime-hating plants. Mains is still fine for tomatoes, veg and most ornamentals. Prefer the butt where you can; do not try to acidify the tap.

The same tests apply to watering houseplants: finger, pot weight, and whether last time’s water actually stayed in the pot. Indoor plants dry more slowly than a hanging basket on a Stockport patio, and overwatering is the usual UK windowsill mistake. This guide is written for outdoor pots, beds and baskets. Do not follow a succulent or snake-plant timetable here.