Summer is the growing season for houseplants, and the season when they need the most attention. Light is strong, growth is fast, and a plant that was watered once a week in winter may need water twice a week in summer, especially if it has spent the season outdoors. It is also the season when plants moved outside enjoy the fresh air and rain, and when the pests that love warm, dry indoor air — spider mites, mealybugs, fungus gnats — are at their most active. This guide covers watering, feeding, outdoor care and pest watch for houseplants through summer, whether they stay indoors or spend the season outside. For local frost and weather advice, check your local extension service.
Watering houseplants in summer
As light and warmth increase, houseplants use more water, and the winter habit of watering sparingly needs to change. Check the soil with a finger rather than watering on a fixed schedule: water when the top few centimetres feel dry for most plants, and let the mix dry out more for cacti, succulents and snake plants. Water thoroughly until it runs from the drainage holes, then empty the saucer so the plant is never standing in water. Plants outdoors need checking daily in hot weather, because wind and sun dry the mix far faster than indoor conditions do.
Group plants together to raise humidity, stand pots on a tray of damp pebbles, or mist plants that like humidity, such as calatheas and ferns, though misting is no substitute for watering the soil. Tap water left out overnight is gentler on sensitive plants, which can react to chemicals in fresh tap water with brown leaf edges. If a plant has dried out completely and the compost has shrunk away from the sides of the pot, stand it in a bowl of water for half an hour so the mix can rehydrate, rather than watering from the top, where the water will run straight down the gap. The watering schedule generator can help you build a routine.
Feeding in the growing season
Feed houseplants through the summer while they are actively growing, using a balanced liquid fertiliser at half the strength on the label, every two to four weeks. Always water first and feed second, because feeding on dry soil can burn roots, and do not feed a plant that has just been repotted for three or four weeks, because fresh mix already contains nutrients. Plants that are not growing — because they are in too little light, or they are stressed — should not be fed until they are growing again, because fertiliser cannot fix a plant that is too dark or too wet.
Flowering houseplants, such as orchids, African violets and peace lilies, benefit from a feed suited to flowering plants once they are in bloom, while foliage plants do well on a balanced feed. Cacti and succulents need feeding only occasionally in summer, at a weaker strength, because they grow slowly and too much fertiliser makes them soft and prone to rot. If leaves are pale or growth is weak despite feeding, check light and watering first — those are the usual causes. The fertiliser calculator can help with quantities.
Houseplants outdoors in summer
Many houseplants enjoy a summer outdoors, and they often grow far better outside than in, thanks to the fresh air, the rain and the stronger light. Keep them in a sheltered spot, out of strong wind and out of direct midday sun at first, and bring tropical plants in if a cold night is forecast — one cold night can damage a plant that has spent the summer outdoors. Check pots daily for water, because outdoor pots dry fast, and check for slugs and other pests that can reach plants standing on the ground; standing pots on a bench or a table keeps them safer.
Bring plants back indoors before the first cold nights of autumn, and do it gradually, in the reverse of hardening off: a few hours indoors at first, building up, and a thorough inspection for pests before they come in, because a pest brought indoors in autumn will spread to the whole collection over winter. Wash leaves, check the undersides and the soil surface, and repot or treat anything that needs it before the plant joins the indoor collection. Our spring houseplant care guide covers the move outdoors and the spring routine.
Summer pests indoors
Spider mites are the classic summer houseplant pest, thriving in hot, dry indoor air and leaving fine webbing and speckled, bronzed leaves. Raise humidity, shower the plant regularly, and remove the worst-affected leaves; a plant kept humid and well watered is far less attractive to mites than a dry, stressed one. Mealybugs hide in leaf joints as white cottony clumps, and they should be removed with a cotton bud dipped in diluted alcohol, checking the plant weekly until no more appear.
Fungus gnats hover over damp soil and breed in it, and the best control is to let the top of the mix dry out between waterings and to remove dead leaves from the soil surface. Scale insects appear as small brown bumps on stems and leaves, and they should be scraped off gently and the plant wiped down. In every case, isolate an affected plant from the rest of the collection until the problem is dealt with, because pests spread quickly in summer. The pest identifier helper can help you identify what you are seeing.
Light, pruning and summer care
Summer light is strong, and a plant that spent winter in a dim corner may need to be moved, but not into harsh direct sun all at once. A south-facing windowsill in summer can scorch leaves that were happy there in winter, so move sensitive plants back a little, or filter the light with a sheer curtain. Turn pots a quarter-turn each week so growth stays even, and wipe dust off leaves with a damp cloth so the plant can use the light it gets. The sunlight calculator can help you check whether a spot gets the light a particular plant needs.
Prune straggly growth in summer, cutting back leggy stems to just above a leaf node, and take cuttings from healthy prunings if you want to propagate — summer is the best season for it, because cuttings root quickly in warm conditions. Remove yellowed or damaged leaves promptly, so you can see whether new growth is healthy, and repot any plant that has become pot-bound during its summer growth, using a pot only one size larger and fresh mix suited to the plant.
A summer houseplant checklist
Water when the top few centimetres of mix feel dry, water thoroughly, and empty saucers so plants never stand in water. Feed every two to four weeks at half strength while plants are growing, and do not feed a plant that has just been repotted or is not growing. Check plants outdoors daily for water and pests, bring tropical plants in if a cold night is forecast, and inspect every plant for pests before bringing it indoors in autumn.
Summer houseplant care is mostly about paying attention: a plant that is checked regularly, watered when it needs it and fed while it is growing will thrive, while a plant left to itself in a hot room will struggle. The reward is a collection that grows strongly all summer and comes back indoors in autumn in better shape than it left. Browse the guides hub for the seasonal guides, and use the watering schedule generator to build a routine that fits your collection.
Frequently asked questions
How often should I water houseplants in summer?
When the top few centimetres of mix feel dry — usually more often than in winter, and daily for plants outdoors in hot weather. Water thoroughly until it runs from the drainage holes, then empty the saucer so the plant never stands in water.
Should I feed houseplants in summer?
Yes, while they are actively growing — a balanced liquid fertiliser at half strength every two to four weeks, always on moist soil. Do not feed a plant that has just been repotted for three or four weeks, or one that is not growing.
Can houseplants stay outside all summer?
Many can, in a sheltered spot out of strong wind and direct midday sun at first. Check pots daily for water, keep them off the ground where slugs can reach them, and bring tropical plants in if a cold night is forecast.
What are the tiny webs on my houseplant?
Spider mites, which thrive in hot, dry indoor air. Raise humidity, shower the plant regularly, and remove the worst-affected leaves. A plant kept humid and well watered is far less attractive to mites.
When should I bring houseplants back indoors?
Before the first cold nights of autumn, gradually, and after a thorough inspection for pests. A pest brought indoors in autumn will spread to the whole collection over winter, so check the undersides of leaves and the soil surface first.