Stop watering a little every day.
A light sprinkle keeps roots shallow. Water deeply and less often, the finger test, and why morning matters.
A quick sprinkle every day wets only the top few centimetres, so roots stay up where the soil heats and dries first. Water deeply and less often instead, a proper soak two or three times a week for established seedlings, and let a finger pushed in to the second knuckle tell you when. Water in the morning, at the base of the plant, and mulch once the seedlings are up. Seed and just-emerged seedlings are the one exception: they want the surface kept constantly moist.
The hose comes out every evening. Thirty seconds on each bed, the surface goes dark, the job feels done. Then a hot Saturday arrives and the lettuce collapses by lunchtime, and the verdict is that the garden needs more water.
It usually needs the same water in fewer, bigger doses.
Why little and often makes shallow roots
A light daily sprinkle only wets the top few centimetres, and roots grow where the water is. Gardening Australia puts it plainly: frequent, shallow watering can encourage roots to stay close to the surface, where the soil is hotter and drier. That top layer is the first part of the bed to heat up and the first to dry out, so a plant with all its roots there is the first to suffer when the weather turns.
Deep watering does the opposite. Water that soaks down draws the roots down after it, into soil that stays cool and damp for days.
How much, and how often
Enough to wet the soil at least 30 centimetres down, then nothing until the soil asks. For established seedlings in spring that usually means a proper soak two or three times a week, more often in sand or heat, less after rain. Perth's Water Corporation works on about 10 millimetres of water twice a week in summer for a Perth garden, which is a useful floor to think in.
The test is the soil, not the calendar.
- Push a finger into the bed to the second knuckle, about 5 centimetres.
- Dry at the fingertip, water, and water properly.
- Damp at the fingertip, wait a day and check again.
When and where to water
In the morning, at the base of the plant. Watering in the cool of the morning loses less to evaporation, and the leaves dry before nightfall, which matters for the fungal problems that visit zucchini, cucumber and tomato leaves in humid weather. Aim the water at the soil, not the foliage, and let it run slowly so it soaks rather than runs off.
Local rules differ by state and season. Perth has rostered sprinkler days and a winter sprinkler switch-off, and Sydney allows garden watering only before 10 am and after 4 pm unless you are on drip or a smart system. Your water utility's page has the current rules; Perth readers can start with the Water Corporation's guide to how much water a garden needs.
Mulch, and how much of it
About 3 to 5 centimetres of loose organic mulch once it settles, pea straw, lucerne or sugar cane. Err thinner with the fine, fluffy mulches, because a thick fine layer can stop light rain reaching the soil at all. Mulch holds the moisture you have just put in, keeps the soil temperature even and shades out weeds. Water first, then mulch. Keep it a few centimetres clear of seedling stems, and wait until direct-sown carrots and lettuce are up before mulching over them.
The exception: seed, new seedlings and pots
Seed and just-emerged seedlings have almost no roots, and they are the one case where little and often is right. Keep the surface constantly moist with a gentle spray until the seedlings are up and growing; a row that dries out even once can be lost. Once they are established, a few weeks in, ease off to the deeper, less frequent soaks.
Pots are the other special case: a pot that drains freely can need a drink every day in warm, windy weather, and shallow raised beds sit somewhere in between, so finger-test both more often than the ground.
A note for every zone
The routine is the same in every capital. What changes is how fast the soil dries. Perth sits on sand, which drains fast and holds little; organic matter dug through the top 30 centimetres and a wetting agent make more difference there than anywhere else, and the soaks come closer together.
Brisbane's humid mornings are the reason to water early and keep leaves dry. In Sydney, Newcastle, Wollongong, Adelaide and Perth the routine starts now; in Melbourne, Geelong, Canberra and Hobart it usually matters from November, when the beds finally warm and dry.
Grow it: seeds in stock
Three spring crops that show the lesson from both sides.
Bean Bush Jadea bush bean whose shallow roots make the lesson obvious: soak it in, mulch it, and it usually copes far better with a hot week.See the seeds
Tomato Heirloom Mixthe crop that punishes uneven watering with split fruit, and rewards a steady deep routine.See the seeds
Lettuce Salad Bowl Greenthe shallow-rooted one that wants the mulch and the finger test most of all.See the seeds
Uneven watering shows up in the fruit later: tomatoes split when a dry spell is followed by a soaking, and blossom end rot, a calcium disorder, is brought on or worsened by irregular water. A deep, regular routine is the cheapest fix for both, and our kitchen thermometer test tells you when the beds are warm enough to plant.
Frequently asked questions
How do I know if the water is getting deep enough?
Dig a small hole with a trowel an hour after watering and look. If the soil is dark and damp 20 to 30 centimetres down you are in the right range; if it is dry a few centimetres under the surface, water longer and slower next time.
Is evening watering wrong?
For saving water, morning or evening both work. The reason to prefer morning is disease: leaves and soil that stay wet all night in humid weather give fungal problems a head start.
My soil is sand and the water runs straight through. What now?
Add compost or aged manure through the top 30 centimetres and water a wetting agent in until it foams, which is the Water Corporation's own advice for Perth. Then mulch. The soaks will still be closer together than on clay, but the water will start to stay.
