Watering & Mulching Your Garden

Sandy soils generally need more frequent watering than clay soils, but less water should be applied each time. Whatever the soil type, do not let plants reach wilting point before you water again. Plants do not thrive on such ‘on-and-off' treatment. Remember, a good soaking encourages deeper roots and soil stays moist for a longer time. Light sprinkling, no matter how often you do it, encourages roots to stay at the surface and form shallow root systems. The subsoil gets drier and drier and becomes difficult to wet again without a lot of heavy soaking.

The best time to water is early morning or evening - before 10am or after 4pm - because evaporation rates are likely to be lower than in the middle of the day.

In humid areas, however, evening watering over plants that are susceptible to fungal diseases will encourage such diseases to flourish, and therefore should be avoided. In the morning it is usually less windy, too, so the water spray goes where you want it. In very dry weather, morning watering may help pollination and seed-setting in some vegetables, particularly sweet corn and beans.

When watering pots, you need to ensure the whole profile of the potting mix is completely saturated. We recommend watering the pot using approximately as much water as the size of the pot, e.g. if you have a 10 L pot, use 5-10 L of water per watering session. Just be sure that you don't over apply the water or water to regularly for those plants that prefer a drier mix. 

Next time, after you have watered, dig a hole near the plant to a depth of about 20cm, if the soil is moist the entire depth, then water is being properly absorbed and getting to where it's needed most - the roots.

If the soil is still dry underneath, then the soil has become water repellent or hydrophobic. Here's How to Fix Hydrophobic/Water Repellent Soils. 

Saving water in your garden isn't hard, but it does require a few changes. Here's what you can do:

• Ensure your garden hose is fitted with a trigger nozzle and manually water your garden to reduce the risk of over-watering. Watering cans can be used for small areas or potted plants.
• In times of drought or during prolonged hot dry spells, apply Yates Droughtshield to plants in your garden. This specialised product protects plants from damaging environmental conditions including heat, water loss, drying winds, sunburn, droughts, light frosts and transplant shock.

• Plant selection: choose drought-tolerant plants to ensure your garden survives when there are water restrictions. There are plenty of beautiful varieties to choose from, including ornamental shrubs and native plants. Check out our list of Drought Tolerant plants.

• Use a soil wetting agent, like Yates Soil Wetter, to help to break down the waxy, water repellent layer that can develop on soil and potting mix. When soils become water repellent or hydrophobic, they repel water and prevent moisture from being absorbed into the soil and taken up by the roots. 

• Install a rainwater tank to capture water from your own roof that can then be used on the garden. Connect it to drip irrigation or a soaker hose to ensure the water is directed to where it's needed most: the soil and plant roots. 
• Water lawns with an automated irrigation system. Smart WiFi systems can take into account the weather forecast and avoid watering when rain is predicted. Avoid frequent mowing in dry conditions as this can cause further stress on the lawn, causing it to yellow and brown. 
• Collect grey water from the home and use it on garden beds. Grey water is water that comes from household washing machines, hand basins, showers and baths.

Mulching is a good way of conserving soil moisture, especially in summer. A mulch is any soil covering which protects surface roots and reduces evaporation. It also helps maintain an even soil temperature and discourages many weeds from growing. Apply a generous layer of mulch to garden beds, veggie patches and pots.

The best mulches are loose materials that allow most rain or irrigation water to run through to the soil. They must also allow free access of air to soil and roots. The depth of the mulch should vary with its coarseness, from shallow for the finest to thicker for the coarsest (2–6 cm). Garden compost, leaf mould, dry-grass clippings, well-rotted animal manure, straw, wood chips, lucerne hay and sawdust are common mulching materials. Do not dig mulches into the soil (especially bark materials and sawdust). All will eventually decompose naturally and become integrated with the topsoil.

Mineral substances, stones, pebbles, gravel and sand will not decompose and are used as permanent mulches in gardens. They're also called 'inorganic mulches' and effectively suppress weeds while still allowing oxygen and moisture to penetrate the soil. 

Over-watering or excessive watering is wasteful because it washes away valuable nutrients. A common mistake is to over-water in winter when plant growth rate is reduced (in the case of deciduous shrubs and trees, the plants are dormant.) Over-watering in winter often happens with summer-growing lawns like couch grass. If a plant is not growing actively, little or no water is needed.

Wet soil may also favour the spread of some fungal diseases, so it is best to keep mulch a few centimetres away from the stems of plants or the trunks of shrubs and trees. Such a moist area may encourage root rots to attack the plant at or near soil level.

This information is from the Yates Garden Guide: fully revised & updated 45th edition, HarperCollins, $39.99. You can have this information and so much more at your fingertips by purchasing the Yates Garden Guide, available at all leading bookstores and Bunnings stores.