Q. How often should I water my California pepper tree, Mediteranean fan palm and my Canary Island date palm These are the only trees I have on my property. I hand water them. How often should I be watering them with the extreme temps we are having?
A. We have to take into consideration both how often and how much to water. The “how often” will be the same. Or in other words all the trees you mentioned will all be watered with about the same frequency.
How much is also going to be about the same except for their size. The larger the canopy, or size of the tree, the more water it uses. This time of year, with temperatures in the triple digits, I would be watering two to three times a week depending on your soil and if you have mulch on the soil surface. Generally speaking, a layer of mulch will save you about one extra day that you do not have to water.
Make sure, though, that you are leaving at least one day dry between irrigations. Watering too often and keeping the soil sopping wet will lead to roots rotting. If soil is piled against the trunk and kept wet, the trunk will rot.
I would suggest that you put a “moat”, depression or basin around the trees to contain the irrigation water from your hose. This depression, if it is maintained so that it stays at the same capacity around the tree, will guarantee that the trees get the right amount of water each time.
|Irrigation basin for watering with surface mulch applied|
The depression can be a moat that is a wide donut or trench around the plants. This can be a small one when first planted but must be increased in capacity as the plant gets bigger. The depression or donut should be 3 to 4 inches deep and wide enough to contain 5 to 10 gallons of water when young and expanded to contain up to 40 gallons when thre tree is larger in a few years.
The only exception to this is the palm. Many palms have the same size canopy when they are five feet tall as when they are 20 feet tall. With the same sized canopy later in life, they will use the same or similar amount of water. So for these types of palms, one sized depression should be fine during its lifetime.
There have been criticisms with this type of watering that letting water surround the trunk might cause the trunk to “rot” or become diseased. Watering with a moat or donut around the tree is far more likely to cause problems if wet soil is left in contact with the trunk.
|Water against the trunks of trees when irrigating does not kill the tree UNLESS you do it too|
frequently and keep the trunk wet. In many cases it is worse to have wet soil against the trunk.
For this reason I prefer a depression around the tree rather than a “moat” or “donut” around it. As long as the trunk dries for 24 hourse after an irrigation, trunk or collar rot will not be a problem. It WILL be a problem, however, if wet soil is left in contact with the trunk. So don’t pile soil against the trunk that will get and stay wet between irrigations.
These depressions should be gentle, sloping depressions and not deep trenches from World War I!. When constructing these depressions, I like to start on the “high side” of the tree and use a common hoe to construct it. Pull soil to the low side when you create the depression so you can “berm” up on the low side and contain the water. The bottom of the depression should be as flat as possible.
Start creating your depression and run your hose with a gentle amount of water coming out. Craft your depression or moat so that the water begins to fill this moat as you are constructing it. Running the water will help you get the bottom of the moat level and fill the basin around the tree without moving the hose.
Buy one of those inexpensive hose water timers that you turn on like a kitchen timer. It will turn off the water depending on the number of minutes you dial in. It will save you water in the long run because, if you are like me, we tend to forget what’s cooking if we don’t use a timer.
Don’t just dig a trench and fill it with water when you are done. It will never be level unless you dig it at the same time you are running the water. This type of irrigation is called “basin irrigation”, a type of flood irrigation but you are using a hose. Fill this basin twice when you water. The basin can also be used for applying fertilizer.