keeping roots cool

bonsaiDerek

Yamadori
Messages
81
Reaction score
13
Location
madison wi
USDA Zone
5a
hi. what do you guys do to keep your trees roots from cooking in the hot summer sun in their dark brown pots?
 
Messages
1,001
Reaction score
1,780
Location
Tennessee
USDA Zone
7a
On my smaller pots this summer i am experimenting with a top dressing of chopped sphagnum (orchid moss) and dried pillow moss. Its gone a long way to keeping my small pots cool and moist while im at work.
 

AZbonsai

Masterpiece
Messages
2,364
Reaction score
4,744
Location
AZ
USDA Zone
9
Burlap
 

Lost2301

Yamadori
Messages
61
Reaction score
89
USDA Zone
5
Try cutting a large piece of dark screening material big enough to lap over the edges of the pot. Cut out a hole in the middle of the screen for the trunk. Place the screen around the trunk. Take a thin piece of wire and wire the cut ends together. If you have moss on the tree, you can use some galvanized wire and cut/bend the wire to form hoops and then insert the hoops into the soil. The screen will then rest on the hoops and not damage the moss. This is also an excellant way to grow new moss on trees, plus it keeps the birds from pulling the moss of the tree. The screen will reduce the amount of light reaching the soil/pot which should keep the pot cooler.
 

0soyoung

Imperial Masterpiece
Messages
6,805
Reaction score
11,172
Location
Anacortes, WA (AHS heat zone 1)
USDA Zone
8b
One can easily measure root temperatures in pots with a simple meat thermometer probe. One from the grocery 'baking' section will do the job and won't cost you much more than $15, if that. You can try different things and monitor until you find a way to keep them below 95F. There is no need to imagine or guess what the root temperatures might be, you'll know and can move on to those problems that are not so easily solved.

The principle thing you will find is that it is not too difficult to keep the root temperatures down as long as the substrate is damp. Once the substrate dries, the temperature quickly sky rockets. So, for the most part, it comes down to reducing the rate of evaporation so the substrate doesn't go dry during the day. Of course, there is more, but a meat thermometer probe could help you figure those things out in your specific circumstances.
 

Shibui

Masterpiece
Messages
2,861
Reaction score
5,429
Location
Yackandandah, Australia
USDA Zone
9?
I agree with @Osoyoung. Many seem to worry unduly about soil temp. I experience many summer days well over 40C and I have not found it necessary to protect pots. I have never seen tree roots 'cook' in pots but I have seen trees dry out and die from dehydration. Keep the water up during hot weather is far more important and I suspect that many of the shading techniques that bonsai growers show off are really just making up for inadequate watering technique.
If anyone wants to use shading there are many threads on this and all other forums with many wild and wacky and some really neat options. Just search.
 

Clicio

Masterpiece
Messages
2,080
Reaction score
4,398
Location
São Paulo, Brazil
USDA Zone
11a
hi. what do you guys do to keep your trees roots from cooking in the hot summer sun in their dark brown pots?
Well, in the hot summers around here, I protect the pots in the afternoon sun.
Wife helped knitting the protective "clothing" for them.
20190314_083728.jpg
 

James W.

Shohin
Messages
474
Reaction score
490
Location
Augusta, KS
USDA Zone
6b
hi. what do you guys do to keep your trees roots from cooking in the hot summer sun in their dark brown pots?
Some things I have done:
Grow in larger pots than "recommended"
Set the pots on the ground.
Crowd pots together to shade each other.
Surround or cover pots with mulch
Set pot inside another, larger pot.
Grow on east side of house. (i.e. morning sun, afternoon shade)
 

sorce

Nonsense Rascal
Messages
28,291
Reaction score
38,400
Location
Berwyn, Il
USDA Zone
6.2
That 1-2PM watering thing has been excellent for me.

Every time I think about how well my roots grew the first time I setup the autowater, I think about how it was not only the water that helped, but the temps.

So cool.

Sorce
 

sorce

Nonsense Rascal
Messages
28,291
Reaction score
38,400
Location
Berwyn, Il
USDA Zone
6.2
Tell us about it, @sorce !

For that Week I left with the setup, come back to 6-12 inch roots running out of the baskets.
Of course, being huddled close together on the ground helped....
But usually the root tips die back about a CM out the basket.

The Long Cold Water helps too.

Sorce
 

rockm

Imperial Masterpiece
Messages
9,683
Reaction score
12,430
Location
Fairfax Va.
USDA Zone
7
Simplest solution--wet down some white, or light colored, sheets/t-shirts/towels, etc. -- I use spare reusable pee pads I've got around for my dog.-- Put them over the pots IN THE MORNING just after you water the trees...I've been using this method for years here in Va.--where summers are a lot hotter than up North. Works very well.

Don't laugh at the pee pads. (they've not been used by the dog--if you're wondering). They insulate the morning cool in the pot and prevent a lot of evaporation from the soil's surface too. The trees they're on remain in full sun all day, pots remain cool all day...
 

Thomas J.

Chumono
Messages
509
Reaction score
1,032
Location
DFW area
USDA Zone
7
These JBP are in full sun no matter the temps and in the summer here in Texas that could be pretty hot for some time. I've been using old sheets every summer for some time and they do the job. I water around 1:00PM and then again at 6:00PM and you can see the results of the health of the trees this way. :)

y2_pe.jpg
 

M. Frary

Bonsai Godzilla
Messages
14,195
Reaction score
21,689
Location
Mio Michigan
USDA Zone
4
Simplest solution--wet down some white, or light colored, sheets/t-shirts/towels, etc. -- I use spare reusable pee pads I've got around for my dog.-- Put them over the pots IN THE MORNING just after you water the trees...I've been using this method for years here in Va.--where summers are a lot hotter than up North. Works very well.

Don't laugh at the pee pads. (they've not been used by the dog--if you're wondering). They insulate the morning cool in the pot and prevent a lot of evaporation from the soil's surface too. The trees they're on remain in full sun all day, pots remain cool all day...
This is the solution.
The white is the best reflector and the fabric holds in extra moisture.
Used Depends undergarments nor used pet pee pads should be used as a substitute for fertilizer though.
 

SU2

Omono
Messages
1,274
Reaction score
349
Location
FL (Tampa area / Gulf-Coast)
USDA Zone
9b
hi. what do you guys do to keep your trees roots from cooking in the hot summer sun in their dark brown pots?
Black containers attract heat worse than lighter colors so use that to your advantage of course. Thin plastic of any color cannot compete with the insulation of wooden boxes (also, in-addition to keeping temps down on a hot day, a wooden box dramatically *slows* temp-changes and, while true-temp is of course a big concern, the speed-of-change in temp can be shocking to sensitive plants so the wood provides a buffer in that way as well!)

That said, the best tricks I've found are:
- Wrap the container for extra insulation, I use a tan-colored, breathable 'shade cloth' for this (the type you'd use to 'roof' a tiki-hut in your backyard), I just cut crude 'shirts' and tie them around a container if it's black-plastic and I'm worried I'm cooking roots!
- Mulch the top of your substrate and, just like with teh container, use something *light* in color! IE even if the organic of your choice is better in terms of nutes/soil-culture, if it's a dark dark brown then I'd sooner choose the inert-but-white Marble-Chip mulches to help deflect heat from the rootmass!

Good luck and, while it's obvious it's something we (well, *I*, at least) can forget, which is simply being sure your trees are in proper locations relative to the sun IE choosing your layout based on sunlight wants/problems of your trees, am actually needing to re-org my garden for this reason as months of re-pots has things way out-of-order, BC's in partial-sun and boxwood in full-sun!
 

Similar threads

Top Bottom