The first things you should do when planning a new garden are,
The result of this is that all trees lean to the East and we had to add a watering system around established trees and shrubs. However, the latter isn't neccessarily a bad thing!
In order to lay piping you would need to have your garden completely planned before you start and, baring those of us who can afford and wish to use the services of a Garden Designer, this is unlikely to be the case.
We started the garden with little idea of what it would eventually look like and suffer from a number of plants which are now in unsuitable places but also others whose serendipitous planting has added, (in our view), to its attraction.
However, to the water!
We have installed Leaky Pipe in the majority of the garden.
If you aren't aware of Leaky Pipe, it consists of old car tyres which are ground up and sintered to produce a porous pipe.
It come in two main sizes; 12mm and 16mm diameter. The 12mm is adequate for domestic gardens and will exude ~ 2l of water per metre length of pipe per hour. There is a range of barbed joints, right-angles and T-pieces so that complex systems can easily be created and, in order to have the most efficient operation, pressure reduction valves are available. We would recommend the use of these as straight domestic water pressure is liable to blow out some joints and any LP taps you have in your systemn.
The pipe should be buried at least 2-3" to ensure against degredation by sunlight and a run of 100m can be taken in one length with a suggested maximum of a 500m total from a domestic water supply, (taken via a doublecheck valve).
The essence of its operation is that water is provided where it is required: in the ground at root level and, because the pipe is buried, there is little loss by evaporation which is not the case for watering by cans.
The map at the left shows the system we have at Redhall.
The earliest areas fitted were the central borders immediately to the west of the house. This area and the bed in front of the house have to be connected up to a hose pipe at the red points shown.
In 2005 it was decided to install a system to water the northern area of the garden.
This was based on a spine of 20mm blue polythene pipe taken off the greenhouse supply and run up to the top of the garden. As this is ~20' higher than the level at the house, I wasn't sure that there would be a sufficient head of water but a test with several linked hosepipes showed that, though weak, there was pressure at the highest point.
From this main spine, various spurs are taken to either feed lengths of leaky pipe, provide take-offs for hose-pipes or both. The points are controlled from plastic valve boxes with removable lids which are buried in the beds.
These are colour coded on the map as shown below.
The polythene pipe is only buried 6 - 9" down so the system has to be drained down for winter as does the greenhouse watering system.