Grow with H₂O

Gardens – big or small - are the area where huge amounts of water are used, in fact, 25-50 per cent of a household’s water use is outdoors. So, while you’re planning what to plant over the warmer months, it is worth thinking about ways to reduce your water use and make your garden water efficient. Collecting rainwater is a good start, but there are so many more things you can do.

Explore the sections below to find out ways to cut down on your water use and make your garden the best it can possibly be.

With the outdoors accounting for 25-50 per cent of a household’s water use, planting plants that don’t require much watering and weaving in tricks to keep moisture in the soil, could make a mountain of difference when the rain isn’t falling. Follow the link below to the Auckland Botanic Garden's website where you'll find useful ideas on designing a water efficient garden that suits the typically dry soil conditions of Auckland.

Invest in plants that don’t need much watering

Not only do mulches conserve water, but they reduce the need for irrigation. They also moderate soil temperature, inhibit weed growth, and over time, improve the soil structure and health of plants. Mulch is an essential component of maintaining a water efficient garden. The basic rule is any mulch is better than no mulch. Kevin Walsh, author of Waterwise Gardening, describes three kinds of mulch in his book.

Coarse mulch

Coarse mulch, like pine bark, pebbles, recycled concrete and bricks make a long-lasting mulch that is excellent for preventing weeds. It is also very good for keeping the soil cool, particularly if it is lightly coloured. This mulch won’t improve the soil much and in the short term will take nitrogen out of the soil. But, this can be compensated for by spreading some nitrogen rich fertiliser on the soil before spreading the mulch. This sort of mulch can be 50-75mm deep.

Medium mulch

Medium mulch, like pine bark or wood chips, is excellent for reducing weeds. This sort of mulch is usually laid 25-50mm deep. One danger with mulches is watering too often - bringing roots to the surface of the soil under the mulch. If the mulch goes or the surface of the soil dries out, when the roots are too shallow the plants die. The solution is less frequent watering.

Fine mulch

Fine mulch, like sawdust and euca can stop water getting into the soil, so don’t make it too thick – about 25mm deep – and top it up each year when the ground is starting to dry out. Pea straw, cow and horse manure, and compost make excellent mulches because they improve the soil and attract worms.

Compost

Compost increases the organic content of the soil which holds water and provides the material that bacteria and worms need to break down to keep your soil full of nutrients. The perfect growing medium is soil that drains easily, but holds enough water to feed your plants. Compost will do both these things.

Without good soil, it won’t matter how much water you put on the garden, it won’t do well. Compost can easily be made at home or check out local suppliers for recycled green waste mulches and compost.

Watering at dusk after a hot day is OK, but moisture resting on foliage overnight encourages fungal diseases. Frequent light watering encourages shallow roots, so aim for longer, infrequent watering which allows the top layer of soil to start drying out before watering again.

Here are some watering tips for the plants in your garden.

Vegetable gardens

Growing vegetables need between 25-30mm of water per week for good growth. If watering by hand, once a week will often be adequate: that will allow the water to soak to a depth of about 150mm. Repeat again when the top few mm of soil have started to dry out.

Fruit trees

The water and feeding needs of fruit trees are normally greater than ornamental plants of a similar size. Mixing plenty of organic matter into the soil prior to planting will not only help the plants access nutrients, but will also help the soil retain moisture, reducing the need for watering. Keep grass and weeds clear of roots and mulch heavily to conserve water.

Ornamental trees and shrubs

Freshly planted trees and shrubs require additional attention to watering while they become established. As the roots grow deeper into the soil, they become less dependent on water available in the topsoil, and irrigation becomes less critical. Heavy mulching of garden beds around trees and shrubs will minimise the need for irrigation.

And, with Auckland Council scrapping resource consent fees for the installation of rainwater tanks on residential properties, there's really no reason not to get one for your property. Here's some ways that you and your garden will benefit:

• Collecting rainwater allows you to be prepared for times of low rainfall, so you can still maintain your garden, especially if there are water restrictions in place.
• Your garden loves rainwater, and you can use it to top up your pool or wash your car.
• Using rainwater can reduce your water bills as rainwater is free.
• Capturing rainwater reduces the load on stormwater systems because roof runoff is not flushed into the drains.
• If you are in the process of planning a new house, think about ensuring the design includes provision for a rainwater tank.

Check out the video below from our friends at Council for what you need for a rainwater tank.

Keeping a bucket in the shower is a great way to collect water for use on the lawn or garden. Tip soapy or excess water from fish tanks over your plants – but remember, some plants can’t handle softeners and harsh detergents, and please don’t use this water on the vege patch.

If, when preparing dinner each night, you wash your vegetables in a bowl of water, that water can be reused to help grow the vegetables still sprouting in your garden.