The short version: Pots dry out fast in an Australian summer because the soil volume is small, the sides bake in the sun, and wind pulls moisture out all day. Water deeply in the morning until it runs from the base, then check the top few centimetres with a finger before watering again. Mulch, a saucer, grouping pots or a self-watering pot all slow the drying. Water and greywater rules differ by state, so check your local authority.
A balcony of pots can carry you through summer with herbs and tomatoes off the vine, until the first real run of hot days. Then the courtyard turns into a furnace, the basil flops by lunchtime, and a weekend away comes home to crisp brown sticks. None of that is bad luck, just what pots do in the heat, and once you see why, you can stay ahead of it.
Why pots dry out so much faster than beds
A pot holds only a small pocket of soil, far less in reserve than a garden bed, and it can go bone dry while a bed stays damp below. The smaller the pot, the faster it happens.
It is not just volume. The sides are exposed to the sun and air, so the mix dries from the edges in as well as the top, and dark plastic and metal heat up most. Add a hot northerly wind, which pulls moisture from leaves and soil at once, and a container loses far more on a windy day.
Water deeply, in the morning
Give pots a proper drink, not a daily splash. Water slowly until it runs from the holes, then come back and do it again, so the whole root ball wets through.
Morning is best. The pot goes into the heat already charged, the leaves dry before evening, and less is lost to evaporation than at midday. A light afternoon top-up is fair in a heatwave, especially for thirsty croppers like tomatoes and cucumbers, but it is a top-up, not the main event.
Your own hand beats any calendar. Push a finger into the top few centimetres of mix: cool and damp, leave it; dry and crumbly, give it a drink. Lift a small pot too, since one that has gone dry feels suspiciously light.
When the mix turns water-repellent
If water sits on top and races straight out the bottom, the mix has gone hydrophobic, or water-repellent. This is common once a mix dries out hard, and it is the classic trap in Perth, southern WA and the dry inland, where mixes and sandy soils repel water worst. The water runs down the gap between mix and pot wall and out the base, the saucer fills, and the middle of the root ball stays dry, so the plant wilts an hour after a good soak.
The fix is to break that waxy surface. A soil wetter, or wetting agent, watered in as directed lowers the surface tension so moisture spreads through the mix rather than channelling around it. For a pot that has dried right out, stand it in a bucket of water until the bubbling stops.
A quick note on your climate zone
Summer is not the same everywhere, so find your zone.
- Tropical (Darwin, Cairns): summer is the wet season, so the risk flips to waterlogging. Use a free-draining mix, lift pots off the ground, and tip out saucers, since standing water breeds mosquitoes.
- Subtropical (Brisbane, Gold Coast): humid summers dry pots slowly but build fungal problems, so airflow matters most.
- Arid (Alice Springs, Mildura): the hardest swings between wet and dry, so wind shelter and a wetting agent earn their keep.
- Temperate (Sydney, Melbourne): shorter heat runs, but a hot, windy day still empties a pot fast.
- Mediterranean (Perth, southern WA, Adelaide): a long dry summer rewards a deep morning water and afternoon shade.
- Cool and alpine (Ballarat, Canberra, Orange, the southern tablelands): the shortest heat windows, so most pots cope; check them on hot days.
Slow the drying: mulch, saucers, size and grouping
Watering well is only half the job. Keeping that moisture around long enough for the roots to use it is the other half, and a few small habits add up.
- Mulch with a thin layer of sugar cane, lucerne or bark, kept back from the stems, to slow evaporation.
- Use saucers in heat to hold a small reserve, but tip out the leftover after a day or two so roots are not sitting wet.
- Go bigger, and choose pale or glazed pots where you can. A larger pot holds more moisture and swings less, and a glazed or light pot stays cooler, while unglazed terracotta breathes and dries faster, so it suits herbs more than thirsty greens.
- Group pots so they shade each other and dry more slowly, and in a heatwave move the vulnerable ones into shade or under shade cloth.
Self-watering and wicking pots
A self-watering or wicking pot keeps a reservoir below the soil, and the mix draws it up by capillary action as it dries, so the plant sips from below. For a hot balcony, or anyone out all day, it is among the most useful tools going for steady drinkers like tomatoes, cucumbers and greens. Browse our vegetable seeds.
They are not set-and-forget: the reservoir still empties in extreme heat, and herbs that hate wet feet can sulk in them. But through a hot spell they smooth out the swings that stress container crops.
Water rules, greywater and going away
Water restrictions and greywater laws differ by state and council, and shift with the seasons, so check your local water authority. In many areas hand watering is allowed even under restrictions, but this varies by stage and location, and a hose often needs a trigger nozzle.
Tipping the shower bucket on the pots is tempting in a dry summer, but mind the food crops. Health authorities advise that you do not use untreated greywater on vegetables, fruit, herbs or anything you plan to eat, so keep it for ornamentals and check the Better Health Channel guidance or your own state. For edibles, fresh water is safest.
Going away is when many potted crops run into trouble. Group them in shade, water well, mulch, and let a self-watering pot, a timer or a neighbour cover the rest. See our guide to the best vegetables and herbs for containers and the pot sizes they need. Get the watering right and a few pots can keep feeding you through the hottest weeks, herbs and tomatoes off the balcony while the rest of the garden is flagging.
Frequently asked questions
How often should I water potted plants in summer?
There is no fixed number; it depends on the pot, the plant and the weather. In hot weather many need a deep water once a day, with an afternoon top-up for small ones. Check with a finger and water when the top feels dry.
Why does water run straight through my pot without wetting the soil?
The mix has most likely turned water-repellent after drying out hard, so water channels down the side and out the base while the centre stays dry. Water in a soil wetter, or stand the pot in a tub of water until the bubbling stops, soaking it from below.
Do self-watering pots work in an Australian summer?
Yes, they are one of the easiest ways to keep up, since the reservoir feeds the plant from below. They suit steady drinkers like tomatoes and greens better than herbs that dislike wet feet.
Can I use greywater on my potted vegetables?
No, not untreated. Health authorities advise against untreated greywater on vegetables, fruit, herbs or anything you plan to eat, and the rules differ by state and council. Keep it for ornamental pots and use fresh water on edibles.
How do I keep pots alive while I am away on holiday?
Move them into a shaded, wind-sheltered spot, water well, and mulch. For a short break, stand free-draining pots in saucers with a small reserve; for longer, use a self-watering pot, a timer or a neighbour. Pots left in full afternoon sun are often the ones that do not make it.
Related growing guides
Ready to plant? Browse our Vegetable Seeds.