How I manage watering to maximise what I can eat from my garden
By Koren Helbig
ABC Lifestyle
Topic:Vegetable Gardens
40m ago40 minutes agoThu 3 Apr 2025 at 1:03am
Koren stands in her vegetable garden, using a watering can to water seedlings in a small raised garden.
Extra watering of seedlings is important as they're getting established. (Supplied: Koren Helbig)
Rewind just a few years and I was terrible at remembering to water my veggie patch.
Hand-watering felt tedious and time-consuming, so I'd regularly skip it and then wonder why my plants fried.
But water is very high up in a plant's hierarchy of needs. Knowing when and how much to water plants has been crucial to eating regularly from my garden — and has helped me double my summer harvests.
Here are tips I've gleaned from learning to water effectively in South Australia — the driest state on the driest continent on Earth.
Knowing how much to water
A rough guide used by many gardeners is that most veggie patches need about 25 litres of water per square metre weekly in summer — although dry climates like mine here in Tarntanya (Adelaide) often need more.
Imagine a standard nine-litre watering can. If you're following the 25L guidance, every square metre of your patch would need almost three of those full, every week.
I've installed drip irrigation lines attached to a $25 tap timer to make the whole process easier. About three 1-hour drip irrigation schedules each week is enough for my plants in summer, though I water more on days over 40 degrees.
A small plastic irrigation pipe runs through a patch of Koren's vegetable garden, on top of a layer of compost.
I installed drip-line irrigation which delivers water directly to plant's roots. (Supplied: Koren Helbig)
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I consider the impact of rain, too. One millimetre of rainfall roughly equals one litre on that one square metre of ground — so unless I've had a solid 25mm-plus of rain in a week, I know I'll need to add supplementary water to my edible plants.
It helps to track rainfall, because sometimes what feels like a heavy downpour can be only a millimetre or two. I use a cheap plastic rain gauge and a free charting app.
Learning soil type
Soil type also affects how much and how often you need to water. For example, sandy soil needs shorter and more frequent bursts, as the water tends to run straight through. Clay soil, like mine, holds water and often benefits from longer, less frequent watering.
There are simple tests, that don't require special equipment, that can help determine soil type.
A hand holds some biochar, which looks like coarse black dirt. A vegetable garden is in the background.
I add biochar along with plenty of other organic matter to the soil to help with water retention. (Supplied: Koren Helbig)
Whatever soil type you're working with, adding more organic matter will help. I use a combination of compost, manure, worm castings and activated biochar.
They can act like miracle workers to improve soil structure. In sandy soils, organic matter can act like a sponge, retaining water and nutrients, while in clay soils, it can improve drainage by adding air pockets.
Watering at the right time and place
I water early morning or late evening, when lower temperatures help reduce evaporation. But better to water anytime than not at all.
I find soaking plants at their root zone, where they need it most, works best — another benefit of drip irrigation.
Newly transplanted seedlings benefit from extra watering in their first week — I treat mine to extra TLC with hand-watering to ensure the entire root ball is soaked.
Considering the needs of individual plants has been helpful. I've grouped drought-hardy edibles, such as rosemary, sage and thyme, together in places where I water less. Thirstier plants, such as tomatoes, cucumbers and eggplants, are grouped in beds where I can easily add extra water.
Reading plants' watering cues
Observation tells me if I'm watering enough. Plants often wilt during the hottest summer days — if they stand back up after the sun goes down, they probably have enough moisture. If not, I know to up my watering regime.
The 'finger test' also works well — I poke a finger deep into the soil. It should ideally feel moist and crumbly. If it feels dry, I water more.
Parched soil requires far more water to re-wet, so I avoid letting it dry out completely.
Helping plants conserve water
Water is a precious resource. These are some simple strategies I use to help reduce watering needs for my plants.
Covering soil with mulch in summer to reduce evaporation. I create mine for free by 'chopping and dropping' weeds, prunings and spent veggie plants, leaving them lying across the ground.
Hanging 50 per cent white shade cloth or an old sheet over plants on hot days — plants won't need to push as much moisture through their leaves to keep cool.
Using plants as shade by growing vertically up trellises and garden arches.
Reusing greywater and harvesting rainwater also helps keep the water bill down.
I'm still often surprised by how much water edible plants need to thrive — but meeting their needs adequately has rewarded me with plentiful bowls of delicious food for the kitchen.
Koren Helbig is a sustainable city living educator who practices permaculture and grows organic food in the backyard of her small urban Tarntanya (Adelaide) home.
Posted40m ago40 minutes agoThu 3 Apr 2025 at 1:03am
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