Saving Water in a Vegetable Garden

, written by Benedict Vanheems gb flag

Mulched raised vegetable bed

With the significant majority of vegetables and fruit consisting of water (somewhere between 74 per cent for sweetcorn/corn and, in the case of cucumbers, 96 per cent) the ability of our crops to access the wet stuff is pretty important in determining the final weight of harvests. It doesn't take the brightest brain to work out that if your plants have access to as much soil moisture as they require, they will grow faster, bigger and better.

Alas, hot, dry summers will either thwart your chances of decent results or necessitate considerable effort applying prodigious quantities of water. Tap water takes a lot of energy to treat and distribute while metred water can prove expensive. With droughts an increasing phenomenon in many parts of the world (even where I am in often-drizzly Britain) the more we can do to reduce our reliance on the tap the better.

Water effectively

In most growing seasons some watering will be needed, but it's not how much you apply that counts, it's when and where. Watering efficiently at the correct time can save many, many gallons of water over the course of the average summer.

Watering plants

Young seedlings and fleshy leaved salads need consistently moist soil if they are to thrive. Other plants are more tolerant of soil that dries out from time to time. As a general rule it is better to water really thoroughly once a week or even every two weeks than to dribble it on little and often. Token watering that merely wets the surface will encourage roots to sit at the surface rather than grow down to seek deeper soil moisture. It will create plants that are completely dependent on frequent watering for their survival.

While soil may look dry on the surface, it may be adequately moist below ground which, after all, is where your vegetables' roots are. Not sure? Just dig out a spade's depth of soil and check the moisture of the soil profile. If it's dry, water well. The object is always to persuade roots downwards to encourage self-reliance.

Watering seedlings

Sowing and planting

Perhaps the biggest influence on how a plant establishes is how it's watered at sowing or planting time. When sowing seeds begin by watering once or twice along your marked out seed drill before spacing your seeds and filling the back with soil. This creates a lovely moist area around the seeds and, in hot weather, will help to cool the ground slightly, ensuring cool-loving veggies such as lettuce germinate without fuss.

Similarly, when planting out young seedlings or plants raised in modules start by filling the planting hole you've made for each plug with water. Allow the water to drain, fill with water again, then allow to drain once more before planting as normal. The advantage of this simple technique is that roots will be encouraged into the soil to ‘chase' the moisture as it filters down.

The same method of filling, draining, filling, draining can and should be applied to the planting of larger fruits trees, shrubs and any container-grown plant. Known as ‘puddling', charging the soil with moisture like this makes a dramatic difference in how quickly a plant gets off the ground. As an added bonus the soil surface is kept dryer, which reduces the inevitable flush of weeds seen when watering from above.

Using mulch to maintain moisture around kohlrabi

Organic matter

No matter what type of soil you have it can always be improved with the addition of organic matter – be it compost, matured manure or anything else that's well-rotted and ready for action. Sandy soils that drain freely will be the first to dry out but the regular incorporation of organic matter will bind the grains of sand together to create more of a crumb structure that will hold onto soil moisture for longer. The mirror image is true for sticky clay-based soils where organic matter will help to form a crumb structure that ensures better drainage while reducing that hard-baked and cracked effect you get during a dry spell.

During the active growing season, with crops in full growth, the same organic matter can be applied as mulch. This slows evaporation from the soil by acting as a physical barrier between soil surface and the drying actions of sun and wind. It will also hamper weeds while providing additional nutrition and steady improvement of soil conditions as resident worms work to ‘dig in' all this goodness. As well as well-rotted organic matter you could also use grass clippings, straw, disease-free veg trimmings or, around fruit trees and bushes, chipped bark.

Collecting rainwater

Of course, as well as conserving water it's good news if what you do apply is rainwater you've diligently harvested. It's free, resource-savvy and better for your plants. Take a look back at my earlier advice on rainwater harvesting.

Filling a watering can

There are other ingenious ways to naturally maximize what rain does fall – useful techniques developed in dryer climates where every drop isn't just valued, it's truly precious. Lots can be taken from our advice in dryland gardening and applied to even temperate regions of the world where dry summers may still be a potential stumbling block.

Lots to do with saving water in the vegetable garden is common sense and can be summed up through these five golden rules:

  1. Feed your soil with organic matter to create a buffer against extreme wet and dry.
  2. The most important watering opportunity is on planting or sowing.
  3. When watering, apply plenty of volume, less often to encourage deeper rooting.
  4. Mulch to conserve soil moisture and improve soil structure. It really works!
  5. Collect as much rainwater as you're able to save using treated tap water.

By Benedict Vanheems.

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Show Comments


"You neglected to talk about drip irrigation. That is a huge oversight."
Leon Springer on Friday 6 September 2013
"Hi Leon. Yes, drip irrigation is of course another big area in which you can save on traditional watering. Delivering water right at the roots, ideally under an evaporation-saving mulch, will ensure far more effective distribution of what water you do apply."
Benedict Vanheems on Monday 9 September 2013
"What do you think of clay pots buried in the ground with a mouth that can be filled. I thought about trying one next year. I have read that you can put a pot in the center of a planing of 4 tomato plants. As you stated it keeps the top layer of soil dryer so weeds may not sprout as easily. I'd love your opinion. "
Vicki on Monday 9 September 2013
"I bury a plastic bottle with the bottom cut off beside my plants like tomatoes, cucumbers, peppers, chilli, courgettes etc and only water through this. It keeps the topsoil dry so less slugs and the water goes straight to the roots. It saves a lot of water in my polytunnel."
Janet on Wednesday 11 September 2013
"Hi Vicki. This sounds like a very good idea as the water would be released gradually at the roots, where it's needed."
Benedict Vanheems on Wednesday 11 September 2013
"Thank you all for your quick responses. I am going to try the clay pot next season and will let you know how it works. they are a bit pricey, but they should last a good while if taken care of and if it helps with the task of watering, it should be worth the effort. "
Vicki on Wednesday 11 September 2013
"I was just at the National Heirloom Expo in Santa Rosa California with my company Dripworks and there were a number of clay pot displays for irrigation. Pretty low tech but they would only serve an individual plant and you would still ahve to carry a watering can or hose. Drip irrigation can take care of an entire garden without having to fill a clay pot on a regular basis. I really have to point out that drip irrigation is the most efficient way to irrigate for flowers or vegetables as well as fruit trees or ornamentals. And its easy and can cover an entire garden off of one faucet too."
Leon Springer on Thursday 12 September 2013
"Can you please tell me more about the red watering can? I'm interested in knowing the brand name and where I can purchase one. "
Pam on Monday 21 July 2014
"Hi Pam. I'm not sure of the exact brand of this watering can. However, I can tell you that here in the UK at least this type of watering can is very common in most garden centres. It is a simple plastic watering can so I'm sure you'd be able to pick one up local to you."
Ben Vanheems on Monday 21 July 2014

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