If you have read my previous articles on soil, compost, plant nutrients and mulching, then you will realise that you are now beginning to understand how to garden successfully. I would now like to talk about watering your garden effectively. A lot of people think they are watering their garden properly, when actually they aren't and their plants are stressed. Watering is not difficult, but there are a few issues to be aware of. Often after we have watered, we notice the water is running down the drive and that it has not soaked into the soil. This also happens with pot plants, that we think we have watered them properly when in reality the watering is running freely out of the bottom of the pot and the root ball is still dry. We also need to be aware that after it has rained, that the water may only have penetrated the top few centimetres of the topsoil and it is still bone dry underneath.
Watering is one of the most important jobs you can do in the garden and it can be very relaxing. Just zoning out, not thinking too much and interacting with nature while you are hand watering can be fantastic. But it isn't as easy as you think. Most people over water their gardens and often plants can survive with less water. In Melbourne (Australia), everyone thought camellias couldn't withstand dry soil, but with our 11 year drought they proved us gardeners wrong and showed they are very tough plants. Plants can become addicted to water, but you can wean them off it, by slowly reducing the amount you give them. For example if you water every day, trying watering every second day, then every third day, then once a week, then once every two weeks. Of course it does depend on the species of plants you have. Azaleas in hot climates will suffer if they are only watered once every two weeks.
Plant Choice
When choosing plants it is important to understand their requirements and these are some questions you should ask yourself:
Do they need sun or shade?
Are they a drought tolerant or swamp plant?
Do they like sandy or clay soil?
Do they come from a hot climate (desert) or a cold climate (mountains)?
Are they a surface rooted plant?
Will they rot if they receive too much water?
Will they die if they receive too little water?
There is an old gardening adage that is it is better to water deeply for 20 minutes three times a week, than sprinkle water over the garden every day for a few minutes. Longer, deeper watering forces the roots to go down after it. Thus the added benefit of this is that soil is cooler in hot weather, giving plants the ability to withstand extremely high summer temperatures. Plants such as azaleas and silver birches are more likely to suffer because they are naturally surfaced rooted. The best way to help these plants is to mulch around the drip line (edge of the canopy).
That is why it is so important to continually improve your soil structure. If you constantly incorporate animal manure or compost you will find that your soils water holding capacity increases dramatically. For established garden beds, the best way to incorporate the organic matter is to put it on top of the soil and let the worms work it down for you, as digging deeply could damage the roots. With new garden beds, the best method is to dig it in to a spades depth.
Watering Systems
I am not a big fan of watering systems, mainly because they don't water evenly and effectively. I understand people who have a big garden haven't got the time to hand water the whole garden, but there are many pitfalls with them. They miss plants, break, get blocked and once repaired are never as efficient as when they were new.
Many people, think that just because they have installed the latest and greatest watering system, that they never have to bother watering again. Well, that is not true. Watering systems need to be checked at least twice a year that they are working properly and you need to check the water is going where you want it too. Pipes have a habit of moving and breaking. Another problem with sprinkler systems is that they just don't have the pressure to pump out enough water for it to soak in more than a few centimetres. If you dig down, you find the soil is bone dry. Sprinklers also miss parts of the garden creating dry spots. It is a good idea to run the watering system and observe what is happening, to see where the water is actually going. Every spring, you need to take the end stopper out of the pipe and run the system to try and flush out dirt, spiders and any other blockages.
In countries where water is precious, drippers are often the preferred watering system. The idea behind drippers is they deliver the water straight to the roots and none is wasted by evaporation. This is true, but often the plants roots congregated around the drippers hole. This often makes plants especially trees unstable in windy conditions because all the roots are in one place (or one side of the trunk). One way to overcome this uneven distrubition of plants roots is to make sure that the drippers holes are regularly and evenly placed. If you have dripper heads on lines, then you can move them around the base of the plant and this prevents a build up of roots in one place. Watering systems are there to supplement the natural rain fall and not to be relied upon to always provide moisture to your garden.
Natural Rainfall
There is nothing that excites a gardener more (especially if you are living with drought) than rain. Everything perks up again and the world seem fresh and clean. We gardeners all tend to think that the rain has given the ground a good soaking and we won't have to water for a while. Well I hate to disappoint you, but often the rain hasn't actually penetrated into the soil and it is still dry. After rain, I recommend you go out into the garden and scratch around under the mulch and plants and observe how damp your soil is. You may get a nasty surprise, that it isn't as wet as you hoped. Also be aware of dry places such as under house eaves, under shrubs and large trees. They may need to be watered.
Too Little or Too Much Water
Insufficient water or too much water can cause plants to become stressed and attractive to insects such as aphids, scale, mealy bug, thrip, mites and white fly. Controlling these pests is going to hit your hip pocket because you may need to buy chemical sprays. If however, you observe that the soil is too dry and ameliorate the problem by increasing the amount of water, then you won't need to buy expensive chemicals. Another problem of insufficient water is that fruit trees often drop their flowers or their maturing fruit. This is a survivable mechanism and it is important at flowering and fruit set to make sure the plant is getting enough moisture. Too much water can also be a problem as it takes up the pore space that is normally fill with oxygen. All plant roots need oxygen and if it is not there, then they will die. In flood, the water takes the space of the oxygen and thus the plant drowns. So drainage is very important.
Pot Plants
And lastly, watering pots can also be tricky as the potting mixes wears out and the pots become root bound. Often you will see water running straight out the bottom of the pot and the potting mix is still bone dry. This is a sign it is time to repot your plant into either the same size pot (with some root removal) or into the next size. Good quality potting mix contains water holding granules, but you can also add your own. I suggest that you hydrate them first, as if you put them in dry, it is very easy to put too much and your plant will suffer and not establish a good root system. It is very easy, just get an old cup, put in 1/2 a teaspoon, add water and leave them for about 10 minutes. When you come back, you will notice they have swelled up and then you can accurately measure the amount you want. If it is a really big pot and impossible to move, one trick is to block the drainage holes with bluetak or something that can be removed later, flood the pot with water and leave it for about 24 hours or until the air bubbles have stopped. This will re-wet the root ball. Then remove the bluetak and allow the excess water to drain away.
Now don't despair and decide gardening and watering is too difficult, as all you can do is your best. But it is handy to be aware of the problems, so when they pop up you can work out a solution or visit your local nursery and get some advice. If you follow the simple rules of adding compost, animal manures and mulching, then you are a long way there to making sure you water and conserve water properly.
http://gardenpatch.com.au/
