It depends. Most tropical houseplants will grow well outside in a UK summer, but only once nights are reliably above 15℃ and only if you acclimatise them slowly. The gain is real for some plants and minimal for others. The risks (sunburn, wind damage, pests, sudden cold snaps) are easy to avoid if you plan it.
We suggest waiting until late May or early June, choosing a sheltered shaded spot, and bring everything back indoors before night temperatures drop below 13℃, usually mid-September in southern England.
When It's Safe to Move Houseplants Outside
UK timing matters more than calendar dates. The trigger is night temperature, not day temperature. Most tropical houseplants will not tolerate temperatures below 13℃ for long, and below 10℃ is dangerous for many.
By region, our rough timing:
- South of England: late May to mid September.
- Midlands and Wales: first week of June to early September.
- Scotland and the north: mid June to late August. Some years you'll get less than that.
Check the 10-day forecast before you commit. A late cold snap, even one cold night below 8℃, can kill or set back a Monstera or Anthurium for the rest of the year.
Harden the Plants Off Slowly
This is the step most people skip, and it is the one that causes most of the damage. Indoor light is far weaker than outdoor light, even on a cloudy day in the UK. Suddenly putting a houseplant outside in any sun gives you sunburn within hours, white or yellow scorched patches that never recover.
Below is our hardening-off routine:
- Day 1 to 3: place outdoors in full shade for 1 to 2 hours, then bring back inside.
- Day 4 to 7: increase to 4 to 6 hours, still in full shade.
- Day 8 to 10: leave out overnight in shade, weather permitting.
- Day 11 to 14: introduce gentle morning sun (an hour or two), particularly for sun-tolerant plants. Avoid afternoon sun.
If you skip straight to step 4, expect scorched leaves on almost every plant.
Where is best to put houseplants outdoors?
The best spot for most tropical houseplants outside is the same as indoors: bright, indirect light, sheltered from wind.
- Under the canopy of a tree.
- On a north or east-facing patio.
- Against a wall that gets morning sun and afternoon shade.
- Inside an unheated greenhouse or a covered porch.
Avoid south-facing patios in full afternoon sun, exposed windy corners, and anywhere directly under a leaky downpipe. Wind is more damaging to houseplants than people expect. Large leaves of plants like Strelitzia nicolai and Ficus lyrata tear in 30 mph gusts; once torn, they stay torn.
Do I need to change my care when growing houseplants outdoors?
Outdoor light, wind and warmth all increase water demand. Most plants will need watering twice as often outside as in. Check daily during a heatwave; a small Monstera in a plastic nursery pot can drink itself dry in 24 hours.
Feed lightly: outdoor conditions push faster growth, which the plant can convert into stronger root and stem if fed regularly. A balanced houseplant fertiliser like Hesi Houseplant Elixir at half strength every two waterings works well. Hold off feeding for 7 to 10 days after moving outdoors so the plant settles first.
Rain is generally a positive: rainwater is softer than tap water and washes dust off the foliage. The exception is plants that hate water sitting on the leaves; African Violets, Episcia and some Begonias are better kept under cover.
Which houseplants thrive outdoors during UK Summer?
Some species visibly accelerate growth and flowering outdoors. Worth considering:
- Bird of Paradise (Strelitzia reginae): more likely to flower after a summer outdoors with regular feeding.
- Monstera deliciosa: often pushes its biggest, most fenestrated leaves of the year in a sheltered shaded summer spot.
- Cacti and succulents: develop better colour and more compact growth outdoors. Echeveria, Crassula, Sansevieria and Aloe all do well in a sheltered sunny spot, but still need hardening off.
- Citrus and olive: if you keep these indoors, summer outdoors is non-negotiable. They want it.
- Hoya: often sets flower buds after a stint outdoors. The temperature swing between day and night is part of the trigger.
- Carnivorous plants (Drosera, Sarracenia, Venus Flytraps): UK summer outdoors with rainwater is ideal for most species. See the carnivorous plants collection for the ones we recommend.
Which Houseplants Are Better Off Staying Inside
Some plants gain little and risk a lot:
- Calathea, Maranta, Ctenanthe and Stromanthe: prayer plants are fussy about humidity, draughts and temperature swings. They look worse after a UK summer outside, not better.
- Episcia, African Violet (Saintpaulia) and most gesneriads: their fine foliage marks easily and rainwater on the leaves causes spotting.
- Anthurium (foliage types): Anthurium clarinervium, crystallinum, warocqueanum and similar. They want still, humid, warm air; the UK garden is the opposite of that.
- Begonia rex and most foliage Begonias: rain and wind shred the leaves.
- Most Alocasia and rare aroid foliage plants: the leaf quality you grew indoors is hard to keep outside.
Watch for Pests
The single biggest risk of summer outside is bringing pests indoors with the plant in September. Aphids, scale, mealybug and slugs all set up shop on outdoor houseplants and travel home with them.
One to two weeks before you bring plants back in:
- Inspect the underside of every leaf and the stems.
- Spray the plant with neem oil as a precautionary treatment, both sides of the leaves.
- Check the underside of the pot for slugs and woodlice.
- Drench the compost (tip the pot on its side in a bath) to flush out any soil-dwelling pests.
- Quarantine the returning plants in one room for a fortnight before mixing them back with the rest of the collection.