Water is a precious resource and the cost is rising all the time. We can all tread a little lighter on the planet by taking a few moments to re-evaluate our garden design and watering habits to eliminate inefficient practices that waste water … and reap the benefits at the same time!
1. Water Pots in the Afternoon and your Garden in the Morning –
Research shows that the timing of when you water pot plants during the day can have a significant effect on plant growth. For watering the garden early morning before the temperature begin to rise, winds are lower and there is less evaporation. Morning watering gives the plants a good supply of water to face the heat of the day.
Fig.1 Water Supply
The research found that plants watered after 12.00 pm and during the afternoon, “significantly outperformed plants grown with early morning irrigation.” So, watering container plants in the afternoon may lead to healthier, stronger growing plants compared to container plants watered early in the morning.
Avoid evening watering especially on the foliage as night-time temperatures are often inadequate to dry the moisture on the leaves which can encourage some fungal pathogens to establish. However, any time plants start to show symptoms of drought stress is the time to water them – even if this means the middle of the day. Waiting too long may be too late.
2. Harvest Water – Save and reuse water wherever you can:
Install a water tank rather than wasting rainwater, to maximize roof runoff and redirect it for use on your garden. Slim line tank and water harvesting systems are available for even the tiniest of spaces.
Fig.2 Harvesting of Water
Save your Cooking Water – If you steam or boil vegetables, save the water rather than tipping it down the sink! It is full of nutrients and when cooled, makes a free fertilizer for watering your plants.
Reuse Fish Tank Water – When you clean your fish tank, use the ‘old’ nitrogen and phosphorous-rich water on your plants.
Use a Compost System – Even micro gardeners can make compost no matter how small a space you might have. Whether you make or buy a worm farm or mini compost system, you will add a valuable water saving resource in your garden. Worm castings and compost hold moisture in your soil and help retain nutrients where they’re needed. Frugal gardeners needn’t buy a compost bin – there are many micro systems you can make yourself. I’ve made several low-cost systems that work well including converting a 60 liter black garbage bin by drilling 1cm holes on the sides and base and covering with the lid. It can be turned regularly by simply rolling it on its side!
3. Choose Your Plant Container Carefully –
Different materials heat up quickly or lose moisture due to porosity so think about your pot location before making a final decision. For example, metal heats up quickly so raised galvanized garden beds and metal containers will draw moisture out of the soil and these gardens will need more watering. If you live in a hot climate, this may be a major consideration. Clay pots such as unglazed terracotta also lose moisture through their porous surface and the soil will dry out faster than glazed pots. If you just have to have that metal or terracotta container, then consider using them as a cache pot (an outer decorative pot) and put a smaller less porous pot inside to retain vital moisture. Use coco peat for increasing water retention quality.
Fig.3 Plant Container
4. Mulch in Garden-
Up to 70% of water can evaporate from the soil on a hot day if you don’t have mulch as a protective layer on top. Mulch is one of the best moisture holding strategies you can employ. It prevents evaporation from the soil surface, helps suppress water-thieving weeds from growing and many mulches add vital nutrients to the soil at the same time. Avoid fine mulches that tend to clump and become water-repellent. Instead, use a coarser mulch which allows water/rain to move down through to the soil. A depth of 3-5cm in a pot (depending on the size) and even deeper (8-10cm) in a garden bed is ideal. Apply mulch onto moist soil and water in well.
Fig.4 Mulch in Pot
Remember, any newly installed plants (even natives and drought-tolerant species) need adequate water until they become established when water requirements will reduce.”
5. Capture Water with Good Design –
Using a variety of design principles in your garden will help you retain moisture where you need it by storing moisture in the soil and can assist run-off in areas that get too wet. Some simple principles to apply are: use plant water-loving species that suck up moisture in boggy areas or use diversion drains, swales and terraces to help intercept water flow and spread it out, so it seeps slowly into the ground where you want it rather than being lost into drains and causing erosion. Build mounds around trees and shrubs to reduce runoff and allow moisture to soak slowly into the soil around the canopy drip line and roots. Good design also applies to pruning: remove unnecessary lower branches and leaves from trees. Not only does this create a more structurally appealing tree by ‘lifting’ the eye up to the canopy, but with fewer leaves there is less moisture loss and this lowers the tree’s water requirements.
6. Increase Organic Matter –
Whilst this comes naturally to most organic gardeners, many don’t realize the benefits of building humus in the soil. Organic matter absorbs many times its own weight in water, which is then available for plant growth. It provides many benefits: clay soils with added organic matter will accept water more quickly and organically amended sandy soils hold water longer, and don’t need to be watered as frequently. One of the easiest ways to build organic matter is to add compost that breaks down to humus. This has an amazing potential to hold moisture, nutrients and build soil health. It has a buffering effect against drought and plant stresses too. You can also add organic matter with worm castings; vegetable scraps; mulches like nutrient rich Lucerne (also known as alfalfa) and pea straw; lawn clippings and leaves.
7. Avoid Overwatering –
This bad habit increases your water bill; leaches valuable nutrients from the soil (costing you money to replace them); causes loss of oxygen in the soil pore spaces increasing the chance of root rot and other diseases from suffocation; and wastes a precious resource. Even worse, it breeds dependent plants with shallow root systems so you’ll never be able to take a holiday without returning home to a garden filled with dried arrangements!
Other Factors That Affect Plant Water Use:
Applying Organic fertilizer stimulates growth and increases plant water use in turf, ornamental shrubs and trees, fruits and vegetables.
Pruning of landscape plants promotes new growth that results in higher water use.
When plants are flowering and fruiting they have greater water needs.
High, frequent mowing of turf increases water use by providing more leaf surface for transpiration however, this type of mowing also increases rooting depth, making the grass more drought tolerant.
Increase mowing height of lawns to allow grass to develop deeper root systems.
Keep the lawn mower blade sharp to make cleaner cuts that cause less water loss than cuts from dull mower blades.
Control all weeds that steal water that would otherwise be available for desirable plants.
Be tough! Don’t waste water on unhealthy or undesirable plants – instead remove or replace them.