Temperature-Based Watering Schedule

post by Ed3120 on Jul 5, 2016

I have a suggestion.

I used to think that midday watering on a very hot and sunny day was bad for the lawn, but I recently learned that was a myth. I’ve been reading and it is actually beneficial to do some light midday watering on hot days to cool off the the soil and reduce the effects of heat stress in the lawn.

I’m going to keep my primary watering early in the morning, but it would be nice to have a second midday schedule that starts only if the temperature is above 85 degrees, and runs for just a few minutes. I can set a schedule to do this every day, but on cooler days, it would be a waste of water.

The simpler way of accomplishing this would be adding a “Only water if the temperature is above X degrees” feature to a specific water schedule.

But heat stress comes into play when multiple hot days in a row strike with no cooler recovery period. A smarter way of implementing this would be “Only water if the temperature average for the past 3 days is above X degrees.” Thanks!

• Cooling off my lawn

post by benblackmer on Jul 5, 2016

Thanks @Ed3120. Could you point me to where you’re getting this info? I’d love to check it out.

post by azdavidr on Jul 5, 2016

I’m also interested in the info. you refer to. It seems that you can use IFTTT to do what you’re asking. I haven’t used the one for the Grass but created it to give you an idea. It fires a watering that you define in minutes whenever the temperature hits a specific value. The other one should enable a fixed watering schedule that I have only when temps rise above 110F.

post by Modawg2k on Jul 5, 2016

I will follow this also to see the original article. I’ve always been lead to believe that too much watering is not healthy for your lawn. In my opinion, the grass canopy should be providing enough shade for the soil until your next watering… which if you are hitting 100+ degrees on a daily basis, I would hope that your grass is being watered at most every 3 days or so. Now if you have patches on your lawn where the grass cannot provide a natural shade, then I guess that’s a different story.

post by sunny on Jul 5, 2016

Generally speaking, watering in the middle of the day won’t harm plants, however it is usually discouraged due to the higher evaporation rate of water being applied to the plants.

The people on this forum reside in many different areas, types of climates and even within their own property, microclimates. There are so many variables, there is no “one size fits all”.

I don’t water during the middle of the day here in the Sonoran desert due to the high evaporation rate. Best practices dictate that a more efficient time to water is in the wee hours to avoid the hottest time of day. Since the nighttime temperature can at times, still be in the high 90s, best practices indicate I should water when it’s cooler–like the chilly 83 degrees we experienced at 6 a.m. this morning. In other climates, it may be OK to water at night.

@Ed3120 is in New Jersey and the Cooperative Research & Extension service at Rutgers provides this publication: Best Management Practice For Watering Lawns

Best Management Practice For Watering Lawns

“Time of Day

The most efficient time of day to water is late evening through early morning (between 10 p.m. and 8 a.m.). It is generally less windy, cooler, and more humid at this time, resulting in less evaporation and a more efficient application of water. Water pressure is usually better at night resulting in a more uniform application of water through sprinklers. Contrary to popular belief, watering at night does not stimulate disease development.”

post by plainsane on Jul 5, 2016

It’s called syringing and you can induce wet wilt as well as increase soil temperatures here

post by plainsane on Jul 5, 2016

I would not water for more than 3-4 minutes assuming you are around 1 inch per hour.

post by sunny on Jul 6, 2016

Interesting article @plainsane. I’ve not been that interested in turfgrasses, but following this forum reminds me of how much time and effort my father put into our front yard. He enjoyed it when the neighbors complimented him on how beautiful our lawn was.

post by dopas on May 29, 2017

dopas1m azdavidr

I don’t think this IFTTT fully allows replacing a water schedule, as IFTTT does not allow to set a specific time when to water.

post by dopas on May 29, 2017

I also would like an option to set a schedule to only water if temperature above a certain value. So this would be similar to the freeze schedule, but instead of below the temperature, it’s above.

E.g Only water if temperature above 20 degrees, better would even be an option that the “high” temperature could be chosen: E.g only water if High temperature of the day is 20 degrees or higher.

This cannot be achieved with IFTTT alone, as specific time needs to be chosen too. IFTTT only allows to water the moment the temperature passes which could be any part of the day, this is not wanted, I want it at a specific time of the day (where no one is in the garden). Thanks.

post by garyjnj1 on Jun 1, 2017

Hi Sunny, I’d say that this theory is in the experimental phase at best. Most standard sprinkler heads installed may not have misting capabilities (I.e., unless each head is tweaked or changed out). Then you have the humidity factor. On high sunny, high humidity/ high heat days, the misted water will sit on the leaves and heat up. Water is an excellent conductor of heat. Excessive heating conditions will develop since the water has no place to go. This will damage the grass.

Nevertheless, If the method is proved out and used, it would not be a daily type of scheduled event. It would require pretty advanced scheduling and would have to take many factors into account including regional conditions, wind speed/direction, humidity, soil type, grass type, etc. Considering these factors, I recommend and prefer the safer, Rutgers method.

post by plainsane on Aug 9, 2017

Sadly enough this behavior is only viable for golf courses where fans can be easily stood up to evaporate moisture.

post by uladz on Aug 13, 2021

This feature was requested multiple times over the past years and it was never implemented. This is really a simple feature to add, and for some reason, the developers are still ignoring it. Sadly :(

post by sandersbud4 on May 12, 2022

It has been 4 years. I want to know whether developers have still implemented this feature or not. It will be pretty disappointing if they have not done it yet.

post by LawnIdiot on Jun 18, 2022

I accomplished this with a couple of IFTTT recipes:

1. Create a recipe with a Weather Underground trigger that triggers if tomorrow's high is expected to be above xx degrees. The action is to create a calendar invite. You can specify that you want the invite created tomorrow as a specific time (I chose 3pm because that is about the hottest time of day).
2. Create another recipe with the Google Calendar trigger of "if any calendar event starts on, then…" (note that this really only works if you have a Google calendar dedicated to this Rachio hack because it triggers on ANY Google calendar event). Add a Rachio action of watering a zone for X number of minutes.

Creating the above should create a calendar invite each day the weather is expected to be over your specified temperature and that calendar event should trigger Rachio to water at the time of the calendar event.

post by djm on Sep 22, 2023

I would love to see this feature too. I had written my own sprinkler controller that I had been using for the last 12 years. One feature that I had implemented in it was in the months from Late May to Mid-Sept if the temperature was above 86F at 6:30pm, it would do one quick cycle across most of the zones.

The reason for this is that around 6:30 would be the time that we might go outside to enjoy the day. And spraying the water for even a little while would noticeably bring temps down and we could enjoy the outdoors.

I would love to see this feature. If I can’t get it, I will probably have to write a script to run once a day at the specific time, check the temp, and then run a quick cycle.