How does your Garden Grow?

Louise Grabell

Most people in our neighborhood are confused about irrigation. Or, they just don’t know much about this process. For now, the soil is very moist so no worries there. However, we will shortly be experiencing some very hot weather. I for one can’t wait! And now is the time to get some education about your irrigation system and practice adjusting your timer, you know, that little white box on the side of your house that says “KEEP AWAY.” LOL.

Before we talk about irrigation, it is most important for you to understand the nature of our soil. Knowing this will help you to irrigate properly and save money [and our precious water]. For the most part, our soil is very clayey. This is the result of erosion and weathering, but that’s another story! In all my house visits to other gardens, I have only come across clayey soil. With this in mind, you need to know that clayey soil takes a long time to absorb moisture and stay wet. Once wet, it stays wet in cool weather. The other side of the story is that once clayey soil is dried out, it is very difficult to get it wet again. This has to do with the poor permeability of clay soils which has to do with the tiny size of its pore spaces, and the lack of interconnections between the pore spaces. It is fair to say that clay soils are porous but not permeable.

OK, so on to how to irrigate properly. Except for xeriscape landscapes and native trees, you will need to properly irrigate so that the soil around your trees and shrubs remains moist. This means slow and prolonged watering once the hot weather arrives. It is best to set your timer to water late at night when it’s cool and there is less evaporation. And you will need your system to run at least two hours, maybe three. The only way to know for sure is to use a soil probe and make sure it penetrates to a depth of three feet. This will satisfy the needs of all your trees and shrubs. Personally, I have never been able to dig a three-foot hole anywhere around my yard, so I just keep an eye on my trees and shrubs and make sure there is no wilting or drooping of the leaves. I try to increase the number of days between watering sessions to six or seven during the months of May and June. If we have good, steady monsoon rain and the soil is wet, then I can set back the timer to once every fourteen days. Citrus, especially, like to dry out between watering sessions. Flower gardens and containers need daily watering when the hot weather returns.

Master Gardeners invite you to visit their website: for all up-to-date information and events for your community. Garden questions? You can reach our very own Garden Helpline by calling Pat at 407-6459.

Remember, nothing brings more tranquility to the heart than a beautiful garden.