Best time to water

[WNC Bonsai]

I am getting my drip system tuned up and ready to turn on again so was wondering what is the best time of day to water? I have heard folks say do it first thing in the morning so the tree will be wet all day. Others say mid-day to afternoon so it will get rehydrated during peak heat and water stress. Yet others say late afternoon so it will have plenty of time to take up water and still dry off before evening comes. The rationale there seems to be letting the foliage dry off so it won’t be subject to fungal attack. Last year I had the system set to turn on at 5PM and run for 5 minutes. This worked until mid summer when I started hand watering again as I had added so many seedlings and collected trees that weren’t covered by the drip system. The drip system seemed to work fine otherwise as the trees grew well but I am always looking for the best combination. This year I also may try adding a few spray heads to improve water distribution. It is difficult though on monkey poles to use spray heads. Will have to search the catalog and see what options are available.

 

[Dav4]

I'd say watering in the AM is best to decrease risk of fungal issues with the foliage, but ultimately, if your trees are in good soil, it shouldn't matter.

 

[Colorado]

I water in the morning before I head to work. But I can certainly see the merit in each argument. I’d love to hear what the more experienced Nuts have to say.

All things considered, I’d imagine it doesn’t matter much so long as the tree consistently maintains the appropriate moisture level.

 

[0soyoung]

About 3 pm = lowest rH of the day = highest transpiration demand/stress & substrate is drying quickly
It is also approximately the hottest time of day --> watering then helps to keep roots cool.

 

[AZbonsai]

We water twice a day here in AZ. Morning and mid afternoon. The only time I had fungal issues is when I misted.

 

[peterbone]

Morning is best if watering once a day. Avoid watering in the evening because tree roots need oxygen during the night and therefore prefer a more aerated soil.

 

[Orion_metalhead]

I water in morning before leaving for work because it helps me get to work on time. It forces me to wake up earlier to water my trees so Im never late.

Trees seem to like it too! They have plenty of water to get them through the morning and afternoon sun. They get shade about 2pm on from there.

I also water a second time when I get home about 430 if the trees look dry.

 

[sikadelic]

I have always watered in the evening when I get home from work or when I am outside working on whatever project is at the top of my list. Usually around 6 PM. I might try watering earlier after reading all the comments just to see if it has an effect.

 

[amatbrewer]

I have my irrigation system set up to run at night when there is the least amount of evaporation because I hate wasting water unnecessarily (same reason I try to use drippers in place of sprayers wherever possible). The ckt that my trees are on ends up running in the early morning. Then I hand water as needed (e.g. really hot days). I don't know if it is "best" for my trees but so far it seems to be working. FYI with my low humidity, rot and such are really not an issue for me.
I also have misters that automatically turn on/off based on temperature in a small greenhouse I use for plants that need additional care/protection.

 

[Nanuk]

I water my trees around 8:30 in the morning.

 

[Emanon]

Is it true that the leaves of some trees (like Japanese maples) might burn if splashed with water during the hottest part of summer days? What about trees that benefit from foliar feeding or watering, such as Sequoiadendron giganteum, Sequoia sempervirens, Cupressus macrocarpa, etc.? Would spraying/misting the foliage of these trees during the hottest part of the day help (keep them cool via evaporation) or hurt (induce scalding)?

 

[Dav4]

Is it true that the leaves of some trees (like Japanese maples) might burn if splashed with water during the hottest part of summer days? What about trees that benefit from foliar feeding or watering, such as Sequoiadendron giganteum, Sequoia sempervirens, Cupressus macrocarpa, etc.? Would spraying/misting the foliage of these trees during the hottest part of the day help (keep them cool via evaporation) or hurt (induce scalding)?

Wetting the foliage with water during the heat of the day won't hurt the foliage and will reduce transpiration demands temporarily... but I wouldn't be deliberately spraying the leaves with ferts or insecticides in direct sunlight, either, as that could actually cause some damage. The best time to foliar feed is early in the am, before sunrise.

 

[amatbrewer]

that the leaves of some trees (like Japanese maples) might burn if splashed with water during the hottest part of summer days

To the best of my knowledge that is an urban legend.
For that to work the droplet would have to be held away from the surface at just the right distance so that the focal point of the light was on the leaf, and the droplets are so small that they are unlikely to be able to concentrate enough energy (imagine trying to use a magnifying glass the size of a water droplet). Making it more unlikely is that a water droplet is not static, so the focal point constantly changing, and it would probably evaporate away before it was able to do any damage.
I read of research done in Hungary (Habor Horvath) looking into if water droplets on a leaf could cause a fire, who concluded the same thing: “On smooth surfaces, such as a healthy maple leaf, no leaf burn occurred.” However he did find some evidence that it might be possible on waxy surfaces with tiny hairs (I believe he mentioned ferns) if conditions were exactly right.

Finally, any slight damage a pinpoint burn could cause (if any), should be far less impactful than the cooling and hydration that result from watering.

 

[Housguy]

Morning for me before work as well. No real reason or science behind it, it is just what I do and the trees seem to like it