Houseplants live in a small volume of potting mix with no soil life to fall back on, so they depend on you for food — but they need far less than most owners give them. A monstera deliciosa fed at full strength every week will develop brown, burnt leaf edges and scorched roots, while the same plant fed at half strength once a month will grow steadily and well. The most common fertilizing mistake indoors is overfeeding, not underfeeding, and it is made with the best intentions: the owner sees a plant that is not growing and assumes it is hungry, when the real problem is usually light or water.
This guide explains when houseplants need feeding, how much to give, which type of fertilizer to use, and how to recognise and recover from overfeeding. The fertiliser calculator can help you work out the amount, and your local extension service can advise on products available in your area.
Do houseplants need fertilizer at all?
Yes, but less than you think. A houseplant in fresh potting mix has enough nutrients for the first few months, and a plant that is repotted every year or two into fresh mix may need very little additional feeding. The plants that need feeding most are the fast growers in small pots — a monstera deliciosa or a golden pothos growing vigorously in summer will use up the nutrients in its mix within a few months. The plants that need feeding least are the slow growers — a snake plant Laurentii or a ZZ raven in a dim room grows so slowly that it needs almost no fertilizer, and feeding it will do more harm than good. A plant that is not growing because it has too little light will not grow faster if you feed it; it will grow faster if you give it more light. Feed only a plant that is actively growing, in good light, with healthy roots — and if a plant is struggling, fix the light and the water first, and feed it only when it is growing again.
When to feed: the growing season only
Feed houseplants only while they are actively growing, which for most plants means spring and summer. Start in early spring, when the days lengthen and new growth appears, and stop in autumn, when growth slows. Do not feed in winter, when most houseplants are semi-dormant and cannot use the fertilizer — it will accumulate in the mix as salts and burn the roots. Do not feed a plant that has just been repotted, since fresh mix already contains nutrients; wait four to six weeks. Do not feed a plant that is stressed, wilted, or diseased, and do not feed a plant that has just been moved to a new home until it has settled and is producing new growth. A good rhythm is a half-strength liquid feed once a month from spring to early autumn, and nothing from late autumn to early spring. If you forget a month, the plant will not suffer — a missed feed is harmless, while an extra feed at full strength can burn the roots.
Liquid, slow-release and organic feeds
Liquid fertilizer is the most controllable option for houseplants: dilute it to half the strength on the label, water the plant first so the mix is damp, and then apply the feed. A balanced liquid fertilizer, such as a 10-10-10 or a 20-20-20 diluted to half strength, suits most foliage plants. Slow-release granular fertilizer, mixed into the top of the mix in spring, feeds for several months and is convenient, but it is harder to control — you cannot stop it if the plant becomes stressed, and it can release too fast in a warm room. Organic options such as seaweed extract and worm castings are gentle and hard to overdo, and they suit beginners well. Avoid fertilizer spikes, which concentrate the fertilizer in one spot and can burn the roots nearby. Whatever you use, the rule is the same: half strength, once a month, in the growing season, on a plant that is already growing well.
Feeding different plants differently
Different houseplants have different appetites. The monstera deliciosa, the golden pothos, and the philodendron Brasil are moderate feeders and do well on a monthly half-strength feed in summer. The fiddle-leaf fig and the rubber plant are also moderate feeders, but they are sensitive to overfeeding and will drop leaves if fed too strongly. The African violet and the anthurium are flowering plants and benefit from a fertilizer with a higher phosphorus content while they are in bloom, but they are easily burnt, so feed them at quarter strength. The snake plant Laurentii, the ZZ raven, and the aloe vera are light feeders that need feeding only two or three times a year at most — and in a dim room, they may need none at all. The calathea medallion is sensitive to fertilizer salts and should be fed at half strength or less, with the mix flushed regularly. When in doubt, feed less: a slightly hungry plant will grow slowly, while an overfed plant may be damaged permanently.
Signs of overfeeding — and how to recover
Overfeeding shows as brown, burnt leaf tips and edges, a white crust of salts on the surface of the mix, wilting despite wet soil, and a plant that stops growing. The salts accumulate in the mix and damage the roots, so the plant cannot take up water even though the soil is wet. If you suspect overfeeding, stop feeding at once and flush the mix: water the plant thoroughly, letting water run out of the drainage hole for a minute or two, and repeat a few days later. Remove the white crust from the surface. Do not feed again for at least two months, and then only at half strength. If the damage is severe, repot the plant in fresh mix, trimming away any black, damaged roots. Prevention is simple: measure the fertilizer, dilute it to half strength, feed only in the growing season, and flush the mix every few months. If you are unsure about a diagnosis, a product, or a local rule, check your local extension service — its advice is tailored to your soil, climate, and the pests and diseases active in your area.
Frequently asked questions
How often should I fertilize my houseplants?
Once a month at half strength, in spring and summer only. Do not feed in winter, and do not feed a stressed or newly repotted plant.
Can I use regular garden fertilizer on houseplants?
Use a houseplant or balanced liquid fertilizer diluted to half strength. Garden fertilizers are often too strong for the small volume of a pot.
Why do my houseplant leaves have brown burnt tips?
Often fertilizer salts accumulating in the mix. Flush the mix by watering thoroughly until water runs through the pot, and feed at half strength or less.
Should I feed my snake plant?
Rarely. Snake plants and ZZ plants are light feeders that need feeding only two or three times a year at most, and in a dim room they may need none.
When should I stop fertilizing houseplants?
In autumn, when growth slows. Feeding in winter, when the plant is dormant, lets salts accumulate and burn the roots.