Watering - high temperatures

Krone

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Is it OK to water the trees for instance in afternoon when the temperatures are still pretty high?
If i water them once in the evening and once in the morning, the soil is still wet in the morning, but if i don't water them in the morning, the soil gets really dry really fast.
The temperatures are around 33C/90F at the moment.

P.S. I don't have the option to protect the trees from the sun.
 

Forsoothe!

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It's almost impossible to overwater a tree in hot weather and full sun in the growing season. You will get rampant growth. That, verses letting it get too dry once and damaging it greatly. A tree that has had enough moisture all day can stand pretty dry overnight. It would probably be better to water once in the morning and let the trees get drier overnight, but that would depend upon winds overnight. If abnormally high & drying winds overnight in addition to hot & dry all day, water twice. Pines can stand a lot drier conditions than deciduous, and it will vary from species to species.
 

Cadillactaste

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I water more frequently with hot days. Drying out can cause dieback...to some species. With this heat...I don't wish to risk it.

I let the hot water run from the hose until it's cool again. It's practically scalding. I then wonder...those with automatic systems. This water that warms in the hoses...must not harm the trees?
 

Krone

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The main issue with me is, and i don't know if this is true or it's just an 'old wives' tale', that if you water a plant when extremely hot, it can cause a heat stroke
 

Cadillactaste

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The main issue with me is, and i don't know if this is true or it's just an 'old wives' tale', that if you water a plant when extremely hot, it can cause a heat stroke
It's an old wives tale. Watered mine three times yesterday. Have done that since I've done bonsai and if they need it...they get watered. these all get strong afternoon sun.
Screenshot_20210629-065211_Gallery.jpg
 

Shibui

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Agreed, along with the idea that water droplets cause leaves to burn.
@leatherback has it correct. Water when the plant needs it.
Every evening and every morning is enough here in summer but I would not hesitate to water in the middle of the day if the plants need it.

Hot water in the hose has already been mentioned. It is second nature for those of us in hot areas to run the hose and test water temp with a finger BEFORE applying water to plants but for those who are not aware yet please be warned.
I let the hot water run from the hose until it's cool again. It's practically scalding. I then wonder...those with automatic systems. This water that warms in the hoses...must not harm the trees?
I guess most auto systems are programmed to water before or after the heat so not a problem. The water in a hose cools within minutes of the sun going off the hose. Hose or pipe travelling through shade or under ground also takes out lots of heat and tiny droplets travelling through the air also lose heat fast so even hot water through micro sprays probably won't hurt the plants. Occasionally I have made a mistake of watering without first running the hot water out but either the plants are tougher or cooler water following the hot is enough to mitigate any problems because I have not seen any problems after.
 

Bonsai Nut

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The main issue with me is, and i don't know if this is true or it's just an 'old wives' tale', that if you water a plant when extremely hot, it can cause a heat stroke
It's an old wive's tale.

Just think about it. If it were true, every time there is a hot day with an afternoon thunderstorm, half the plant life in nature would get nuked. Let me guarantee you that I have weeds growing between black slate pavers in my back yard, where the slate gets so hot that you can't walk on it with bare feet, and yet they thrive after every rain.
 

hinmo24t

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we have record temps for this time of year today and tomorrow, near RI

95*+ and 90%+ humidity

i opened my picnic table umbrella and huddled trees under it this morning, got up 45 minutes early. watered everything pretty thoroughly...at work for 9 hr shift meow
 

ConorDash

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Is it OK to water the trees for instance in afternoon when the temperatures are still pretty high?
If i water them once in the evening and once in the morning, the soil is still wet in the morning, but if i don't water them in the morning, the soil gets really dry really fast.
The temperatures are around 33C/90F at the moment.

P.S. I don't have the option to protect the trees from the sun.
Also, in addition to what others have already said, I take the advice of not watering in the evening. Once the sun has gone down or near enough, no need to water. The plants won't transpire so much plus the dew overnight will hydrate them.
If you water in the evening, theres a chance the trees stay wet for longer, and thus increases risk of fungus.

Im sure many have watered for years in evening without issue but this is just generally the advice, which makes sense and I follow for the most part.
 

pamboys09

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Well its hard to give you whats the correct watering, but what i can do is to share what am i doing to keep my trees healthy.

In my area avg temp in summer is from 98-105
My trees are under 50% shade cloth and only water it once a day. My soil are the typical bonsai soil ( pumice , akadama, lava )

I have pines in full sun ( all day )
I water two times ( 7am and 3pm )

Hope this helps you a bit
 

RKatzin

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One of the biggest dangers during these times of extreme temperatures is hot pots! I like to get in a good watering in the morning while it's cool. Usually getting hot before I'm done. About mid-day I make it rain, spraying the foliage and soaking down the deck and benches and cooling the pots. Then again in the early afternoon I make another round of watering. I hate going out in the heat especially out into the sun where most of my trees are. But I figure if I'm this uncomfortable out here, how are the trees doing. So I point the shower straight up and let it rain down on me. Now I know how my trees feel when I turn it on them. You can almost hear a big collective "Aaaah, that's nice, Ricky!" Nobody calls me Ricky, twice, but all my trees do. LoL
 

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Let's not forget that your plants will telegraph needing water by drooping/wilting, or losing their leaf luster. We look at the plants while watering and if we do not see classic signs, then they are probably not too dry. There's dry and then there's dry. Wet, dry, wet, dry is the normal cycle and any plant that can't take modest drought for a short period wouldn't be very successful in the wild.
 

PA_Penjing

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Something that has helped me big time since going to 10 hour shifts is wrapping light weight and light colored fabric around smaller pots and pots of trees that don't come from hot areas of the world. Then I wet the fabric after for some ambient humidity. When I take the fabric off the pots at night the soil is still nicely moist and many degrees cooler than the soil in the pots that I just let bake in the sun. On really really hot days I'll wrap the pot of every tree, but my collection is very small so it's not a big chore. If you decide to do this just make sure you remove the fabric every night so the soil can breathe and dry out a little.
 

Pitoon

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You can water anytime, as long as you give the leaves enough time to dry out by evening. You should however avoid wetting the leaves if you can as wet leaves in the evening/overnight will assist in fungal attacks.
 

Forsoothe!

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You can water anytime, as long as you give the leaves enough time to dry out by evening. You should however avoid wetting the leaves if you can as wet leaves in the evening/overnight will assist in fungal attacks.
An Old Wives Tale at best. Most places in the world have dew from an hour after sundown to sunrise, so if damp leaves were really key to fungal attacks, then there wouldn't be many plants without disease. (And, no chlorine in dew!)
 

AZbonsai

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I water 2x a day when temps between 105f and 114f...3x a day at 115f + Trees would be crisp if I did not.
 

Cadillactaste

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Also, in addition to what others have already said, I take the advice of not watering in the evening. Once the sun has gone down or near enough, no need to water. The plants won't transpire so much plus the dew overnight will hydrate them.
If you water in the evening, theres a chance the trees stay wet for longer, and thus increases risk of fungus.

Im sure many have watered for years in evening without issue but this is just generally the advice, which makes sense and I follow for the most part.
The only time I'm watering at night...is in fall when I'm expecting frost. To set in dormancy...when temps will be colder and it's windy. I read to do that somewhere .
 

Pitoon

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An Old Wives Tale at best. Most places in the world have dew from an hour after sundown to sunrise, so if damp leaves were really key to fungal attacks, then there wouldn't be many plants without disease. (And, no chlorine in dew!)
"Old Wives Tale" or not......fungus likes conditions with high moisture. That's the reason why in a home the first place mold will show up is in your bathroom if it's not properly ventilated.

Keep JM maple leaves constantly wet in the evening/night and soon enough you'll have powdery mildew or leaf spot on the leaves.

Don't believe me try it.............I grow plenty enough plants to know 😁
 

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