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Drip Irrigation is the most efficient way of applying water to your plants and borders. You can even use it for your lawn (this will be covered in another blog). It applies water directly to the soil at a low rate thus reducing summer evaporation losses, runoff and general water wastage.

So what is it? Well, we could get all technical (its a very sophisticated product) and discuss things like uniformity coefficients etc. However it is basically a plastic tube (brown or black in colour) with a hole punched at pre selected intervals. The secret is that behind the hole… stuck to the inside wall of the pipe is a dripper.

Rainbird landscape drip pipe from Buy Irrigation

Rainbird landscape drip pipe   

This is a moulded plastic (and sometimes rubber or silicon) component that is designed in such a way that  water passes through it to the outlet hole at a constant rate thus watering your garden.

Behind a drip pipe outlet

Behind a drip pipe outlet

The key to any drip pipe is that this rate of application from each hole is constant along the length of the pipe so that your border gets the same amount of water, and your plants grow at an even rate. Also, that the outlet doesn’t get blocked with scale or debris.

To ensure that the drip rate is constant we would suggest a pressure compensating (PC) drip line. The rubber or silicon membrane within the dripper automatically regulates each of the drip outlets along the length of the pipe irrespective of the inlet pressure ensuring that the drip rate is constant. A pressure compensated drip pipe is also the most suited to sloping ground ensuring accurate outlet rates. There are non pressure compensated drip lines available which are a bit cheaper, but it is worth installing a PC product in order to avoid clogging of the drip line firstly ensure the water is clean enough. If there is any risk of contamination install a filter with a mesh smaller than the drip outlet. Also select a dripper with a high degree of resistant to clogging. The plastic moulding is basically a cleverly designed maze that guides the water to the outlet hole. In simple terms the larger the passages of the maze the better the resistance to clogging.

The anatomy of a pressure compensated drip outlet

The anatomy of a pressure compensated drip outlet

In order to avoid clogging of the drip line firstly ensure the water is clean enough. If there is any risk of contamination install a filter with a mesh smaller than the drip outlet. Also select a dripper with a high degree of resistant to clogging. The plastic moulding is basically a cleverly designed maze that guides the water to the outlet hole. In simple terms the larger the passages of the maze the better the resistance to clogging

That’s about as technical as I am going  to get. There are many products on the market with different and specific features that may be applicable to your application but for most, the above is all you need.

The next bit is how you use it. So, you have a border that you want to water. Its one that is suited to drip irrigation…not all borders are. Borders that you are digging over regularly for instance are not ideally suites as ‘those damn pipes’ are always in the way. Measure the width and length of the area to be covered and determine whether you want to water the whole border or just specific areas or specific trees or shrubs.

If you want the water the whole area think about the soil type you have. Is it sandy and free draining at one end of the scale or heavy clay at the other. Most are likely to be somewhere in-between. Of course if the soil is free draining the water will rapidly head through the soil profile downwards. For heavy clay the water will spread more laterally. This will determine the dripper spacings along the pipe and the row spacing across the beds.

How water behaves for different soil types

How water behaves for different soil types

As a general rule we would use a drip pipe with a outlet spaced at 30 to 33 cm apart for most garden applications. Foe a row spacing you would typically use anything from 0.3m to 0.6m apart depending upon the soil type. Without getting very scientific there are exact no rules, it may be a ‘try it and see’ situation. You will certainly see if your spacings are too wide. If in doubt contact Buy Irrigation and we can advise.

Finally before installation check the manufacturers recommended maximum pipe length for one single line. If you exceed this recommendation the even application may be compromised.

Installation is simple, just lay the pipe along he bed at the correct spacing in a grid formation. You can secure the pipe with some soil stakes that dimly clip over the pipe and push into the ground. At the ends use a header pipe again using drip pipe or more commonly plain pipe with no holes and using push in barbed tees, elbows, joiners and end stops connect all together with a single feed from the bed to your water source.

Drip pipe can be laid directly on the soil surface

Drip pipe can be laid directly on the soil surface

You can hide your drip pipe under mulch or just bury it below the soil surface. Both methods with help in spreading the water due to capillary action and contact with the growing medium.

If you want to water a line of trees or a hedge you could just snake one line of pipe along the length. For wider hedges use one at either side of the hedge base.

For vegetables just lay the pipes along the line of your crop

For vegetable gardens lay your drip pipe between the rows

For vegetable gardens lay your drip pipe between the rows

Once you are at your water source, you may choose to install an automatic timer to control the system during the night when most efficient.

Rain Bird ZA-84 battery powered tap mounter controller

Rain Bird ZA-84 battery powered tap mounter controller

Finally, as a general rule, a domestic tap from the water mains will comfortably run a 100m roll of standard drip pipe at 0.33m outlet spacing and a rate of 2.3 litres per hour per outlet. This would mean that you would water a bed 25m long x 2m wide with pipe installed at 0.5m spacing.

So you have bought your pipe got a water timer assembled your system and waiting for the sunshine. A few watering tips to get you started.

  • Water at night to make the best use of your water… the ground and ambient temperature is at its lowest thus reducing any evaporation losses.
  • Firstly establish a wetted growing medium. This may mean you need your watering system on for longer at first. Once the area is dampened you will only need to maintain the ideal growing conditions.
  • Consider wether your border benefit from a single watering for a long duration or multiple irrigation cycles.. If your soil is more clay it may be preferable to water ‘little and often’ to reduce any puddling or runoff. Set your timer (if you have one) accordingly
Drip pipe watering directly on the soil surface

Drip pipe watering directly on the soil surface

Finally, don’t forget to adjust the watering system as the seasons or weather changes. As with your lawn mower, fork, or pruning shears, your drip irrigation system is a tool that needs to be used only when needed. Don’t expect to switch the system on at the start of the year and off at the end without adjustments. You will waste water and have an inefficient system

Happy Planning

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