What has prompted me to write this is that I actually have a lot of practical experience with drip at my own home and also at the company I sold eight years ago (2007). I have messed around with drip and been forced to do some experimenting over the years.
I will get right to the point. We have lots of large and small pots around the house that have seasonal flowers in them. Pots dry out quickly. When it is 100 degrees or more in the sun, if you don’t water the container at least once a day you will lose the plants. I was at a swimming pool the other day that had 12 large containers that cost over $60.00 each to plant each spring and fall. Because the drip irrigation was not put in properly, the plants were on the verge of dying.
$720.00 is a large cost for a small swim club.
1. Improper installation
One of the issues here was that the tubing size was not correct for the emitters used. The emitters readily slipped out of the spaghetti tubing in fact one had come lose and the spaghetti tubing was lying on the ground behind the pot where no one would see it. The plants were dying from lack of water and water was being wasted. I was told by the landscaper that when they planted the pots and put the spaghetti tubing and emitter in the pots that several of the emitters came off. In my experience, the emitter is difficult to put on the tubing and takes some effort. Once it is on the tubing I have never been able to pull them off, I usually cut them off and then use a sharp knife to get the residual tubing off the emitter.
There are other common problems with installation but I want to get to something very important concerning the present heat wave.
2. Proper scheduling for the drip zone.
Typically a shrub bed will be adjacent to some pots with flower in them, and the installer will hook the drip line up to flower pots. That makes a little sense, but in reality it does not.
Here is why. The amount of water for the shrub is probably going to be much greater than for the pot, and the run time be 30 minutes every other day as an example. The pots could easily die if exposed to sun and wind and yet would be over saturated on the day of watering. Running the drip on the shrubs every day would probably flood them plus waste a lot of water. You could set the drip to come on 3 times during the day and reduce the run time by 1/3. It would be better to force the shrubs to develop deeper roots and run it every other day as an example and let it run longer. Some times in extreme heat like we have just had, you might want to extend the drip just to the pots alone.
3 What worked for me.
Here is how I have done it. For many years I did just like the example I used above. Then when I retired and time to analyze the system, I ran a separate run of Netafim blank ram line. That is 17 mm tubing with no emitters in it all the way to the pots at the back door and then continued to the front yard and did the pots there. This allowed me to have all the pots that had the potential to dry out to be on the same system. We also pulled a little mulch over the line from the back yard which helps keep chipmunks from gnawing through the line. see How to Control Rodents Around Drip Irrigation
I then set the controller to water on Zone B. 3 times a day. I chose 8:00 AM, 11:00 AM and 3:00 PM. for 3 minutes 7 days a week. In the larger pots I have two emitters and in the smaller ones I have one emitter. As it has gotten really hot, I have increased the time to four minutes. I was not seeing any water in the tray under the pot. Not all the pots have a tray under them. By not seeing water, meant that I was not wasting water, but also maybe I was not applying enough. With four minutes run time, I am now seeing water in some of the trays but it is not running all over the porch. Previously, since the porch was not perfectly level excess water flowed back toward the house and actually cause some water damage. To try to cut back on the water, I removed one of the emitters and half the plant died. I finally replaced them both when I set the separate irrigation zone to come on multiple times a day.
Photo shows the one of two plants thriving on the front porch, and now they are too big, and I need to do some serious pruning. No way to get away from some maintenance. The lighting is not good but you can see the emitters under the plant.
The other photo below shows multiple flower pots by the back door. Directly to the right is a thermometer on the wall and in the shade of the house for most of the day that reads 108 degrees F. There is also marginally some water in some of the trays under the pots indicating that there is enough drip irrigation to moisten all the soil but not flood the porch.
There are many ways to set up drip irrigation but this worked for me.