(This post was written by Dave Feinglass, who grows dozens of fruit trees on his property in Fallbrook, San Diego County. Thank you, Dave!)

There is just something relaxing about watering the plants in your garden or your backyard fruit tree with a trusty old watering can or your garden hose. But when you get up to a certain size, watering by hand becomes impractical, so we turn to automatic sprinkler timers to make sure everything we grow gets watered on a schedule. Sprinkler timers have been around for many decades, the original ones were mechanical and they lasted 30 or more years. Interestingly, Rainbird asked people to find the oldest one in operation and in 1997, a “RainClox” timer from 1964 that had survived a tornado that destroyed the house it was in, made its way into the Rainbird Museum.


Eventually more functional electronic timers were developed with more features, and today automatic irrigation is part of every new home and certainly every large garden and bigger farm operations. As technology advances and the internet connects everything we own together, Smart Sprinkler Timers are now becoming the standard, offering functionality that finally does what technology should do, make our lives easier…. Usually.

So what makes a Sprinkler Timer “Smart”?

The word ‘smart’ is slapped on just about anything that is connected to the internet these days, whether it should be or not. Refrigerators, coffee makers, garage door openers, thermostats and all sort of lights, outlets and switches can all be turned on or off using an app on a “smart phone” or a PC.

Sprinkler Timers are no different, so you may find a “Smart Irrigation Timer” that is really just controlled by an app, using your home Wi-Fi, to provide the same basic functions that sprinkler timers have been doing for decades – turning valves on and off via a schedule.

While this provides some convenience, such as not having to run to the garage to turn on a sprinkler zone to test it, if you have half an acre or more, you may not have Wi-Fi coverage out in your grove , so it’s not always that convenient.

In my humble opinion, what actually makes a device smart is if the designers anticipate ways to make it read your mind and do what you want done without having to constantly manage it.

A truly ‘Smart’ sprinkler timer would do for us those things we would do ourselves, such as check the weather today (or this week) and adjust the watering accordingly, skip watering if its too windy, or if rain is forecasted or recently occurred, and it would adjust the whole schedule automatically as the seasons change. Fortunately there are now several models from trusty reliable old vendors like Rainbird, Hunter and Orbit, and several newcomers like Rachio, Netro, Rain Machine have models that do most all of these smart features, each with their own approaches. More on the smart sprinkler choices a little later.

How does a Smart Sprinkler Timer adjust for weather?

Apart from programming them with an app on your iPad or phone vs a dial and keypad on the old school timers, probably the biggest benefit to a smart sprinkler is automatic weather adjustments. Each vendor has their own set of specific ways that they implement weather adjustments, but they generally all revolve around the concept of EvapoTranspiration, or ET. Simplified, I like to call ET the measure of how much a plant “sweats” due to heat. Just like people sweat, plants lose more internal moisture when its hotter, so they need more moisture added to avoid drying out. ET aims to measure that amount in terms of “inches of water per day” that a plant loses based on a baseline and then the variance in temperature. 

Most smart sprinklers let you set some parameters about your plant’s environment such as soil type, slope, sun/shade, root depth and type of plant. It then estimates how much water your plant needs based on the weather. It may adjust the frequency of watering, or the duration, or both, depending on how you set it up and which brand/make/model you own.

But here’s the rub… we’ve all heard the expression “if you want something done right, do it yourself”. Be prepared that your “Smart” sprinkler timer may require an awful lot of setup, tinkering, monitoring and adjustments, before it can truly take over the decision making for your garden. In many cases, setting up a fixed schedule, just like your 25 year old “dumb” timer did, and then letting the smart timer only make season adjustments and rain skips, works most reliably. In any case, don’t expect to just plug and play a smart sprinkler timer and have it water the way you wanted, this technology has not quite found the sweet spot between simple and powerful, so there is a learning curve.

Smart Sprinkler Timer choices

When I decided to look at a smart sprinkler timer, the first thing I did was look for reviews online. Virtually all the reviews I found placed one brand at the top – Rachio. Their newest “Rachio 3” model comes in 8, 12 and 16 zone options, and has all the features I described above, plus some other valuable goodies, and some quirks that may send you in another direction. 


First, it uses what it calls “Hyper Local Weather” which means, if you have a weather station nearby (hint, check out Weather Underground, you probably do), you can select it for your weather source. Even better, if you buy a weather station and share it with Weather Underground, you can use your own backyard station for weather info to adjust your watering. We know that even in our own yards the micro climate can vary a lot, so getting weather info from 10 feet away from your trees is better than getting it from across town. My station is by Ambient Weather, about $170.

Rachio 3 has very powerful options for creating flexible schedules that let the algorithms do their thing, but again, be prepared to tinker a lot. I mean, a lot! When I first entered in my parameters for my 8 avocado trees – soil type, slope, sun, root depth, sprinkler inches per hour and efficiency, zone size, crop coefficient and allowed depletion – the Rachio set up a schedule that would have left my trees dry and thirsty. After playing and watching and adjusting, I got it to water the avocados the way I had been watering, but let it make adjustments for heat automatically. Specifically, to avoid tip burn that comes from brief watering durations with our salty water, I always want my watering duration to be consistent and a little longer than needed for the trees actual ET. I didn’t want the Rachio to adjust the duration, only the frequency as it gets hotter in the summer. This is how Greg has shown us in this wonderful blog.

As I mentioned, this technology is cool but not perfect. It didn’t know that avocados need more water than some other “trees” which is the generic option it gives you (other options are grass, shrubs, garden, etc). I had to adjust numerous settings and tinker to get it just right. If you are a tinkerer, it can be fun. If you want to set it and forget it, just make a fixed schedule and let it make “seasonal adjustments” for you.

One other downside is that the units cannot be combined to make more than 16 zones, so if you need more than 16, you will have independent timers that don’t share a common schedule, so you will have to manage that on your own, maybe with a spreadsheet. Other models from brands like Hunter and Open Sprinkler allow you to connect multiple controllers into one, giving you one schedule across up to 70 plus zones. If 16 or less zones is all you need, most all the smart sprinklers below will work well.

Other brands

I have not played with too many other brands, below are some neat features of other models that may be interesting:

RainMachine Touch HD-12, Cloud Independent Smart Wi-Fi Irrigation Controller, Compatible with Alexa, 12 Zones

RainMachine is expensive compared to its peers, but it offers a “local data only” option, which means it doesn’t store any of your data in a “cloud”, it keeps it all local. It has a cool color touch screen and lots of local weather options.



Netro and Yardian make less expensive smart timers that have all the cool weather adjustment features. The Netro has an optional soil moisture meter which can inform the timer that the soil is dry and needs water – kinda like how Greg tells us to get our hands dirty and see what the soil actually feels like.


If you are considering one of these smart timers, carefully consider where it will be located in your yard – most of these are NOT weatherproof, which means they will need to either be mounted indoors or placed in a weather proof enclosure outside.

Automation, now for the cool stuff

All of these smart timers work with other services like Alexa, Google Home, etc, so you can set them up to be able to say “Alexa, tell Rachio to water the Avocados” and it will do it. I find that a bit gimmicky and less useful than using my smart phone to tell it exactly what I want to do. And that voice activated stuff can’t let you create or modify a schedule, which is where most of your time is spent anyway.

Where these integrations really start to shine is the ability to connect the smart timer with other things through a free service called If This Then That or IFTTT for short. IFTTT allows you to connect your smart, well, almost anything, and then have one smart device tell another smart device to do something. Last summer, when I was travelling for work, a heat wave hit and my young avocado trees dropped all their fruit. Since I already had a weather station that was connected to IFTTT, I added my Rachio 3 to IFTTT and created what IFTTT calls an “Applet”. Applets are super easy to create, no tech experience needed, just your device passwords, and again, it’s free to use. 

All of the Smart Sprinkler Timers I mentioned above work with IFTTT.

The applet I created does this: IF tomorrows Weather Forecast is to be over 95 degrees, THEN run the Avocados Water Schedule. This preloads the soil with plenty of moisture in anticipation of the hot weather. I then also created one that says IF the Weather Station current temperature rises above 100 degrees, THEN tell Rachio to water the Avocados for 90 minutes. This makes sure that even if the forecast is off by a few degrees, if it does get really hot the avocados get their extra water. I’ve found it’s hard to over water during a heat wave but the young fruit will thank you for it. The applets have run twice this year already and my trees kept all their fruit this time, and I didn’t have to do anything but watch it all work.

Because I also lost a whole season of growth when the surprise frost hit this past February, I also hooked up the weather station and IFTTT to a smart outlet plug, which I will connect to incandescent Christmas lights strung around the trees come November. Then the applet will do this: IF the temperature drops below 35 degrees, THEN turn on the smart outlet. This will power up the Xmas lights and provide heat around the trees, even when I am sound asleep at 4 AM, or travelling for work.

Technology works best when it works for us, with us, and not simply exists to give us options we don’t need. Smart Sprinkler Timers have the potential to manage our watering routines really well, and with automation like IFTTT, provide 24×7 management to make the watering routine completely hands off. If you’re willing to invest the time to set them up properly, they just might give you back enough time to go grab that old watering can and relax with your little green friends.

A list with links to all Yard Posts is HERE

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