The Background:rainmachine

This is what I have been using to keep my plants alive and watered consistently. It is the HD-12 from RainMachine and retails for around $239. RainMachine also makes a 16-channel irrigation controller.

This controller is a “smart” controller that downloads weather reports from NOAA to update the amount of irrigation your plants receive.

The Setup:

I am going to skip the mundane here, connect to the wall, connect power, blah, blah, blah. You can consult the instructions for all of that information.

After connecting the individual irrigation valves to the controller, you will name them so you can keep track.

    • Setting the max watering duration: This is can be difficult, but again you just have to pick a number and then adjust based on how your plants respond. If you live in Southern California you can try this Watering Calculator to help you with your estimate.
      • The HD-12 has the option for Cycle & Soak, which is great for my clay soils to limit the runoff and wasted water. This is the recommended way to water plants any way, to give time for the soil to capture and store the water.
      • I also like that the controller can schedule the watering every X days, rather than scheduling for days of the week. That way the watering happens on a more consistent schedule, rather than setting a Monday & Friday watering schedule where the plant sometimes waits 4 days between watering, and other times it just waits 3 days.
    • Program your zip code, and the RainMachine takes care of the rest. Your programs run independently and the HD-12 will scale back the watering based on the weather, humidity, and expected transpiration.
    • Make sure to select the options for extra watering on hot days, and that the irrigation turns off if it goes below a certain temperature.

The Results:

I am comforted that the HD-12 takes care of the detailed watering decisions on a day-to-day basis. I just setup the high-level plan and the controller takes care of the rest. My only interaction now is fine tuning the system or adjusting for seasonal requirements of my plants. I rarely change the program running, and my plants are happy about that. I find that I more often make changes to the irrigation lines instead, such as adding or removing lines, or opening / shutting valves. You can’t expect that the controller will know that the banana plant is fruiting and its time to increase the watering, or that I put down seeds and I need the micro-sprayers to keep the top surface moist, but it does automate the everyday decision making and keeps my plants happy and, more importantly, healthy. The HD-12 has the added benefit of reducing the amount of water we use each year, saving us a small amount of money.