Here in late April, it’s about time to water my deciduous fruit trees for the first time since winter. I water most of my fruit trees — both deciduous and citrus and avocado — using micro-sprinklers. Micro-sprinklers are small emitters that work on low water pressure and the same tubes as drip irrigation, but instead of dripping, micro-sprinklers spit, spray, emit fans or jets of water, or spin and sprinkle water in broader patterns.
I’ve had good results watering trees with micro-sprinklers, and in this post I want to share how I’ve found it best to place and configure these micro-sprinklers under fruit trees, including which types of micro-sprinklers I prefer for different situations, as well as modifications I make to them.
Why water fruit trees with micro-sprinklers?
If you’re wondering why one would choose to water fruit trees with micro-sprinklers in the first place, very briefly, the advantages compared to drip include being easier to adjust as trees grow bigger, and that there’s a larger wetting pattern so trees are more resilient in heat or drought. And as with drip, micro-sprinklers are a method of irrigation that applies a small amount of water at a time so they are an excellent choice for trees on slopes because there will be no need for basins and still no runoff — even less than with drip.
Where to place micro-sprinklers
So before needing to irrigate, I’m giving things a run through, starting the sprinklers spinning to make sure they’re working after months of winter idleness.
Spinning just fine. Putting down a band of water under the canopy of this Dapple Dandy pluot tree.
Brightening up the shade under the canopy, you can notice where the micro-sprinkler is located:
Uphill from the tree. The reason for that is there is always a certain amount of water that dribbles down the micro-sprinkler and its stake instead of spraying outward. I want that leaky water to go into the soil uphill from the tree so that it is not running or percolating away from the tree but rather toward the tree (roots).
Second, the micro-sprinkler’s stake is inserted about a foot (a shovel’s length) away from the trunk. Closer to the trunk and the trunk would block much of the spraying water. Farther away and the spray will not be able to cover as much of the ground directly under the tree.
The particular micro-sprinkler used on this tree is made by an Australian company called Antelco and it has a wedge on one side, as seen on the right side of this photo:
You can aim the wedge toward the trunk of the tree, and the wedge splits the sprinkles of water essentially creating a pie-shaped dry area so that the trunk is not wetted. This is good because if you water often and you’re wetting the trunk, then you are creating the conditions that crown-rotting organisms thrive in. Also, trees prefer to drink from small roots growing farther away from their trunk.
When using a micro-sprinkler that doesn’t have a wedge, you can place a stick between the sprinkler and trunk to deflect water and keep the trunk mostly dry.
(For more on the topic of wetting tree trunks, see my post “Keep mulch away from tree trunks?”)
So that’s where I place micro-sprinklers under my fruit trees, but some people prefer to place sprinklers between trees, for example . . .
Look at all that bare ground that has been wetted, that is unlikely to have many roots underneath, and that is surely very prone to evaporation. This can be a less efficient way to irrigate unless trees are large and close together.
But I also don’t place micro-sprinklers between trees because the micro-sprinklers would be in the walking path, plus it inhibits your ability to water each tree individually.
I like to grow many fruit trees but I have a water budget so each of my trees has its own micro-sprinkler that I tune to apply water to that tree as efficiently as I know how.
An indispensible component of watering fruit trees efficiently with micro-sprinklers is having adjustment valves. Some micro-sprinklers have adjustment valves built in. Here’s that Antelco micro-sprinkler with the wedge again:
That dial on the bottom controls a valve that allows more or less water through. But you can also insert adjustment valves into the feeder tubing of any micro-sprinkler. This is what I usually do. Here are the adjustment valves that I buy (available at any irrigation or home improvement store):
And here is one of those adjustment valves inserted into the tubing of a micro-sprinkler:
This allows you to adjust the output of each micro-sprinkler according to each tree’s needs so that you can water trees of different ages and sizes all at the same time while giving each your best guess of how much water they need.
Small new trees
This is another pluot tree, a Flavor Grenade variety, planted in January as a bare root. So it’s been in the ground for only about four months, and I’ve yet to install irrigation to it.
I now need to set up a micro-sprinkler under this tree. Unfortunately, I can’t use one of the Antelco micro-sprinklers shown above. Here is what happens if you try to water a small tree with a spinning micro-sprinkler:
Spinning micro-sprinklers need a certain amount of pressure in order to revolve properly. If the pressure is too low, they don’t spin and just shoot a single stream of water as in the photo above. But if you open the adjustment valve to increase the pressure and get them spinning, they shoot water too far away, beyond the root zone of such a small tree.
So spinners are best used on bigger trees where you want the micro-sprinkler to cover a larger area of ground, at least five feet in diameter, as wide as your wingspan, is my rule of thumb.
For small trees, such as the Flavor Grenade pluot, I use micro-sprinklers that spit.
Makes and models of micro-sprinklers
Luckily, there are a few manufacturers of micro-sprinklers that make products with interchangeable spitting and spinning fixtures. The one I installed on the Flavor Grenade is made by DIG, a company based in San Diego County. This micro-sprinkler comes with three spitting fixtures in addition to a spinning fixture. Here is a pack of the DIG multi-head micro-sprinklers:
And here it is running under the Flavor Grenade pluot tree:
You’ll notice that the wetting pattern is not exactly a circle but a more of a clamshell shape. This is done with the 180-degree fixture (red), which I use on most small trees.
After a couple years, once the tree’s canopy is about five feet in diameter, all I do is switch out the 180-degree fixture for the spinning fixture. It’s a five-second job, and it doesn’t require purchasing anything new. Now I’ve got a micro-sprinkler that spins and applies water in a circle under the tree, just as with the Antelco micro-sprinkler used on that Dapple Dandy pluot tree shown earlier.
This DIG model of micro-sprinkler has become my favorite to start trees on in part because of this versatility. I can buy one micro-sprinkler and use it to irrigate a tree from the first irrigation through the time the tree reaches maturity. I also tend to use these DIG micro-sprinklers for new trees because they are so widely available for purchase. My local Home Depot carries them and I can buy them online. (They’re here on Amazon, for example.)
I keep most of my fruit trees small though. I’ve found that the DIG multi-head micro-sprinkler works well up to a diameter of about 15 feet. Beyond that, it gets susceptible to wind.
Why? It’s all about droplet size. The DIG multi-head micro-sprinkler has a relatively small orifice that pushes out small droplets. The farther you ask small droplets to travel, the more they become wafted into the atmosphere.
For fruit trees that are larger than 15 feet, micro-sprinklers with larger orifices and bigger droplets work better at getting water onto the soil and down to the roots.
DIG makes micro-sprinklers with larger orifices, and I’m sure they work well, but I’ve always used micro-sprinklers made by Antelco and Philmac for larger trees.
If you are watering a tree with a diameter greater than 15 feet or if you live in a windy place, go with a micro-sprinkler with an orifice close to a tenth of an inch in size. For example, the red Philmac has an orifice of 0.094 inches and its droplets are big and very stable in a breeze.
Where to buy micro-sprinklers?
I’ve also bought Antelco micro-sprinklers at Grangetto’s. But you can find Antelco micro-sprinklers for sale from Antelco through Amazon here.
Note: Both Philmac and Antelco also make micro-sprinklers that have interchangeable spitting and spinning fixtures, and they work great. Antelco’s model is called Rotor Rain, as seen here on Amazon.
There are other manufacturers of micro-sprinklers out there, but I’ve only used these three many times and over the course of a number of years. I can comfortably recommend them.
Video showing micro-sprinklers under avocado trees
This shows how I use micro-sprinklers under my avocado trees specifically, but even under my apricots or oranges or apples I configure and run micro-sprinklers almost the same.
Happy Irrigation Season, 2019! I wish you a good watering year, and if micro-sprinklers are involved, then may yours spin to satisfaction.
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