I had an email ranting at me for the sin of using a sprinkler. Fair question although rudely put. Now I don’t accept that watering vegetables is a waste of water so it comes down to the most efficient way of watering. This can be the trusty watering can, a soaker hose, drip systems and so forth. But for a large area a sprinkler is efficient.
Sprinklers deliver the water in droplets which will sink into the soil rather than run off. They can be more efficient than just pouring on water from a can.
Operated with a little care and thought, in the right place, a sprinkler is not wasteful. But all watering should be done thoughtfully, especially in times of scarcity.
When to Water
I like to water late evening so the sunshine doesn’t evaporate water that can sink into ground. Early morning watering is nearly as effective but avoid the hottest parts of the day.
Types of Sprinklers
There are many different types of sprinkler available but I find metal impulse sprinklers to be most effective and durable. They are also called impact sprinkler by the way. There are very cheap plastic versions but they are not as durable.
You can get them on a spike that you push into the ground or on a tripod which improves throw distance and is better when running over raised beds.
Set the sprinkler so that it only waters the area you want to water. The impulse type of sprinkler can be set to cover a defined arc or go in a complete circle by adjusting the friction collars.
Spray Type and Throw Distance
By adjusting the diffuser screw at the water outlet on the sprinkler you can adjust the spray type making it long and narrow or more misty and wide. Some enable you to adjust the throw distance with an adjuster screw on the top of the sprinkler head but it is as easy to do that by controlling the pressure from the tap.
It’s well worth spending half and hour getting to know how to get the best out of your sprinkler.
Amount of Water / Timing
Just as some crops are ‘hungry’ requiring more nutrients than others, some are thirstier. Potatoes, for example, need a lot of water to produce tubers and dry runner beans are not going to produce for you. You need to judge how dry the soil is and how the crop is doing before watering. With potatoes I would be generous but with established carrots or parsnips not so much.
It’s simple to work out how long to leave the sprinkler running for. Using a rain gauge or just a straight sided bucket, even a saucepan or jam jar will do, you can measure how much water is delivered over a period of time.
Each inch of water is equivalent to about 4½ gallons per square yard or each centimetre is equivalent to 10 litres per square metre.
I tend to start with 1 inch (2.5 cm) of water initially and then increase the amount if necessary.