Water Smart Garden Tips

1. Water Pots in the Afternoon and your Garden in the Morning. The timing of when you water potted plants during the day can have a significant effect on plant growth. Pine bark based potting mixes however have low moisture retention properties, meaning pot plants dry out more quickly.

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.

The optimal watering time for the rest of the garden, is early morning before the temperatures 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.

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 roof top rain water collection tank rather than wasting rainwater, to maximize roof runoff and redirect it for use on your garden. Check with your local municipality for rain water collection incentives, it can save you a lot of money!

Save Cooking Water – If you steam or boil vegetables, save the water 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 changed water that is nitrogen and phosphorous-rich 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. There are many easy do it yourself tips on building or making composters on the internet. Most people have what it takes to make one already in their yard.

Bokashi – (fermented grain) bins are another efficient way to compost food scraps and add moisture to the soil. They are available commercially but if you’re a thrifty gardener you can easily make your own. All you need are a couple of buckets the same size – one fitted inside the other with holes drilled in the base of the top one to allow the liquid (fermented juice) from the scraps to drip into the base of the lower bucket. Finally, fit the lid to the top bucket. You then just dig the scraps into your garden or add to the compost and dilute the juice to use as a fertilizer.

There are also many DIY worm farm options providing you with valuable worm castings that are pure humus and hold maximum moisture in your soil or invest in a commercial one

3. Mulch, Mulch, Mulch! 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.

4. 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. 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.

5. Reduce the Impact of Water Guzzling Plants – Species with low water needs will save you time and money in the garden. These include: established or slow growing plants, small plants, varieties with small or narrow leaves, grey or silver foliage such or plants with leathery, hairy, curled or fuzzy leaves that typically require less moisture

Large leafed plants require and transpire more water over a larger surface area than slender leafed varieties. Leaves that reflect more of the sun’s radiation (e.g. gray or silver) usually lose water through transpiration at a lower rate than green leaves. Plants that can tolerate higher leaf temperatures also evaporate water at a lower rate. For example, herbs like small fine-leafed rosemary and thyme have minimal water needs compared to larger leafed basil and sage. Natives and succulents may make better choices than some of the more common landscape plants, so do a garden ‘audit’ and make water-wise choices.

6. Check Weather and Soils – It might seem obvious but how many times have you watered your garden, only to have it rain soon after? Turning off automatic sprinkler systems if rain is forecast is one sensible step to save money and water. Also, consider your climate, location and the season. Weather factors that impact watering include: cool temperatures, high humidity, the winter season, shade and no wind which all reduce the need for irrigation whereas hot, windy summers with low humidity will increase the need for watering. Include some tall species or garden structures that will provide more shade in your garden where possible.

7. Use a Moisture Meter – This inexpensive tool will help you get a feel for what each of your plants need in terms of moisture. It is easy to use and provides you with an accurate reading of the moisture content in your soil in a few seconds. 10-30% moisture indicates the soil is too DRY and you need to water; 40-70% moisture means the soil is MOIST or ‘just right’ so no action is required; and a reading of 80-100% moisture means your soil is too WET so avoid watering. Alternatively, use a screwdriver or chopstick as a soil probe to test soil moisture. If it goes in easily, don’t water; if it won’t budge then grab a watering can! A watering can is also a good way to make sure you only water as much as you need to.

8. 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.

9. Increase Organic Matter – While 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.

When adding ‘raw mulches’ to the garden which is called lasagna mulching or to the compost remember to keep the ration 70% carbon such as dried leaves or shredded newspaper to 30% nitrogen, vegetable scraps and grass clippings. This prevents the compost from becoming slimy and stinky which means it’s anaerobic and is not supporting the microbes which help to break down the mulch into humus.

10. 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 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.

Information Resource Credit: Anne Gibson

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