Drip Irrigation Basics
Work and social media have been inundated with folks that have irrigation issues. Most of these problems are coming from drip systems and I think it is high time for me to write about it.
How Much Water Does the Plant Need?Drip can be a great water saver, especially in dry western states. This is because a good drip system puts the water where you need it rather than everywhere. But by the same token you need to make sure you put water in the right place and in the right amount or the plant will die. There is very little mercy or room for error in a drip system, so you need to make sure you do it right. The first thing you should look at is how much water the plant needs when it is planted. If you are planting from pots, find out the size of the pots and if they’re quarts or gallons. You will want to water anywhere from a quarter of that volume to a half of it, as a minimum. So if you have a one gallon pot you need to have at least a quarter gallon of irrigation every time you run it to make sure all of the roots have a chance at getting water. If the plant is ball and burlap you will need to estimate the volume of the root ball and then divide the results by four. This will give you the approximate amount of water needed to give a full water load to the existing roots.
Picking an EmitterAfter you have figured out the volume of water you will need to pick an emitter. Emitters are usually sold by how much water they can deliver in an hour. Keep in mind that the amount of water we have already talked about is only the amount that is needed to keep the current root ball wet, you will also need to take into account that the root ball is going to grow and the soil around it is going to need to be watered so that new roots will move into it. The amount of water you will need for that is going to vary a great deal depending on your soil, so I will not be covering that other than to say you need to be ready to experiment. By now I hope that you have noticed that if you have both large trees and smaller plants, you are going to need vastly different amounts of water for the different sizes of plant. Please take this into account when you chose the emitter size. You may also choose to use more than one emitter per plant, especially for the trees. When you place the emitters, you need to make sure they get water into the root ball. If they are pointed upward the water is more likely to run down the tubing until they hit the soil. If that soil is outside the root ball, your plant is going to get very little water or none at all. Once you have the system operational, test it to make sure that the water is going where it is needed and don’t just assume it.
Set Up the ClockThe last step is to set the time on your irrigation clock. If it does not run long enough all the work you put into design and the money you spent on the system is wasted. If you run it too long you’ll lose out on the water savings. The time you need will be variable and will depend on the gallon per hour rating of your emitters and the number of them you are using, so it will take some math to make sure your plants are getting enough. But just to keep you in the right frame of mind, I have never seen a drip system that can be run effectively for less than an hour. And truth be told, most systems I have seen need to run for multiple hours. If you have an older or cheap irrigation clock it is going to be hard to get the length of watering time needed to handle a tree. You may need to get a new clock, but you will also find that creativity and knowing the features of your system can correct some of the limitations to your clock’s capacity.
As you can tell, there are a lot of factors to consider in order for a drip system to work right. And once you have it set it will take tinkering on a regular basis to make sure it keeps up with growing plants and their growing need for water. Even though this seems like a hassle, it guarantees you will be spending quality time with the plants that you love, so look at it as a blessing!