Garden Irrigation – A Complete Guide

How to Irrigate Your Garden

A garden can often be seen as the definitive feature. It can be used as a place to relax, socialise and enjoy with family and friends, while it can also be used to grow plants and vegetables. However, getting the best out of your garden can be time-consuming and laborious as it will need to be properly looked after and maintained regularly. One of the key aspects needed to achieve this goal is to ensure that all the plants and vegetation are well watered. This can either be done manually by watering cans, or it can be carried out by installing an effective garden irrigation system. This article will discuss the latter, and briefly outline how a decent garden irrigation system can be fitted.

Before outlining these steps, it is worthwhile noting that installing a well-designed irrigation system can be expensive and quite physically demanding, but the results gained will easily justify the work that needs to be put in.

Water Pressure

Before any type of garden irrigation system can be installed, your water pressure will need to be checked. This is to ensure that the right components are chosen for your garden as this will affect both the planning and the result. To measure your water pressure, purchase a pressure gauge and follow the instructions outlined. This will usually involve attaching it to your gardens outside tap in order to gain a reading.

  • An ideal water pressure will be between 3 and 8 bar
  • If your water pressure levels are below 3 bars, then you may have issues operating standard sprinklers or other components. If this is the case, a booster pump will be required
  • If your water pressure is too high (above 8), this could damage your gardens irrigation equipment. A pressure regulating valve can be installed to solve this problem
Garden sprinklers are a great and cheap method of garden irrigation.

Garden sprinklers are a great and cheap method of garden irrigation.

System Design

A well-thought out system design is arguably the most important factor when it comes to garden irrigation. This design template can be applied to any garden, but generally, it will be better suited to smaller one.

  • Draw a scale plan of your garden and make sure that you accurately note the positioning of the lawn, flowerbeds, trees, and any other important features. To do this you will need to measure your garden
  • You will then need to purchase sprinklers and decide where they’re going to be located. The water that a sprinkler produces will need to overlap the next one and so on so that no spots are missed. This idea needs to be applied to all pieces of irrigation equipment
  • Sprinklers are best for lawns, but other types of equipment are better for getting water directly to the plants. Micro tubing will be able to supply water to the roots of all plants
  • Consider where you are going to connect your system. If there is a tap in reach, then the bottom of the riser that holds the tap up will usually provide adequate connection. However, directly attaching your irrigation system to the outlet of the tap must be avoided because this will significantly restrict the flow of water
  • Consider where the trenches are to be installed. These trenches will use pipes to move water away from the connection point towards the irrigation equipment
  • Micro misters provide a lighter and more delicate spray for younger, smaller plants. These are best fitted in the greenhouse if you have one
  • Micro jets are typically fitted onto stakes that measure up to 35 cm. These are great for flowerbeds and borders
  • For larger vegetation such as hedges and whole vegetable patches, the use of a soaker hose needs to be employed. These will be able to provide heavy duty irrigation, while a smaller version is recommended for hanging baskets and grow bags.
This is a full blown garden irrigation system!

This is a full blown garden irrigation system!

For a properly irrigated garden, all the above items will need to be purchased. Each one of these will cover different areas and distances, and so it is vital to work out what these are before buying them. Typically, the radius that sprinklers and other equipment will cover will be measured in meters, but remember to provide some leeway to account for overlapping. This overlapping is referred to as a “head-to-head” layout, which is essential if you want to provide sufficient irrigation and avoid neglecting patches.

Installation

Now that you have done a significant amount of planning and have purchased equipment that suits your gardens requirements you will need to install it. This will involve digging trenches that allows piping to be laid, which will in turn supply water to the irrigation equipment. Of course, this can be done alone as a DIY job. However, there are specialists who will be able to offer home maintenance advice and even install your system for you if required.

  • Locate the water connection point which was identified in the planning stage (probably near or part of your outside tap). Start digging the trenches from this point
  • Dig the trenches so that they correspond with the planning stage. They will need to be 400mm deep and roughly the width of a spade
  • Connect the piping as necessary, and make sure that a tight seal is formed at all connection points
  • Test the water irrigation system before covering the earth back over the trenches. Ideally, all the equipment should cover the radiuses highlighted in the specifications
  • Backfill the trenches being especially careful around the connection points

There is of course a lot more work that needs to be done than the steps highlighted above, but they will vary depending on each gardens requirements. However, here are some general pointers:

Gardening is an important part of irrigation.

Gardening is an important part of irrigation.

General

  • Make a note of where the trenches run. This way you can avoid damaging the pipes that lie in them
  • The levels at which your run your irrigation system will depend on a number of factors, including the soil and the plants that you are trying to grow. Generally, 12 minutes, 3 times a week will be sufficient for most gardens in the UK. Reduce this by 50% in the winter and 75% in the autumn due to chances in precipitation levels
  • Installing a weather monitor that automatically adjusts running times based on the weather is a useful tool. These monitors account for seasons and microclimates, ensuring that your plants get the proper levels of hydration
  • Should you require an unlimited supply of free water (domestic users only) you may want to consider installing a borehole irrigation system. This simply means drilling down to the water table and installing a pump to draw water to the surface. The diameter of this hole would be approximately 100mm
  • First, you will need to establish how deep you will need to drill to locate a good supply of water. Go to the British Geological survey website and search to see if any borehole records exist for your location
  • Drilling the borehole is the expensive part. You should allow £100.00 + per metre. Boreholes are drilled using a static or mobile rig, which is a bit like a small oil rig so you will need good access to the site. Many specialist companies have the equipment to complete this type of work
  • Once drilled the borehole needs to be fully or partially lined depending on ground conditions
  • Finally, a borehole pump connected to a PVC pipe is lowered into the hole. The pipe diameter is dependent on the type of pump required, and the type of pump will vary based on the distance the water needs to lifted (this is called the dead) and the amount of water required (volume per hour, expressed in either litres or gallons.)
  • The other end of the PVC pipe is usually connected to a storage tank. The size of the tank depends on the amount of water you require to be available at any specific time
  • The garden irrigation system is then connected to the storage tank

Borehole

An irrigation system can help keep your garden healthy

An irrigation system can help keep your garden healthy

Summary

  • Find the water
  • See how much capacity you can draw from the borehole. This is something that the drilling company will be able to provide you once it is drilled.
  • Work out how much water you need over what period of time. This will be determined by the irrigation system you are installing.
  • Determine what sized storage vessel is required.
    • Then use the correct capacity pump to match the demand.

Overall

Installing a proper irrigation system, either on a DIY project or through a professional, is different from simply dotting a few sprinklers around the garden. They can be quite expensive, and they require a lot of planning and hard work, but when fitted, they will create results that surpass any other watering system. This guide has briefly looked at a few of the factors that you will need to consider, but as each garden has individual circumstances, a basic guide can only be provided. For a more thorough and in-depth analysis that guarantees results, it is advisable to contact an experienced building contractor or landscape gardener in your local area.