How do you determine when to water?

LouisianaNative

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I'm a newbie, and trying to understand watering my bonsai. I have 5 right now. Two junipers, a Trident Maple, Chinese Elm and a small cypress tree. I live in a hot summer humid climate, North Louisiana, USA. These trees are in the sun about 6 hrs a day. Is this enough sun? It seems that the soil is moist, even after a day or so. I don't want to over water them. The Maple is dying, or at least I think it is. It has lost all it's leaves and hasn't had any for months. Scratching the trunk with my fingernail still shows green, but I'm not feeling good about it. The soil is always moist it seems. Too moist??? Could that be the problem? Watering these trees is a challenge. Mostly because I'm a beginner, and I simply don't know what to do. Any help? suggestions? Thanks in advance.
 

TN_Jim

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Please explain your soil in every way -how did it become what you’re working with now, what sort of container is it in, and if possible, photos.
Maybe, don’t water today
 

Lochamp

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Many maples are understory trees and need less sun than one would think. Morning sun and afternoon shade is good normally. If you can't do that than you can also put a shade cloth over it.
 

0soyoung

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Deciduous trees will loose turgidity when they are too dry - you want to water just before this happens. When the substrate/soil has run out of moisture that can be utilized by the tree, the leaves will get 'droopy'. When like this, you should note how the soil/substrate feels - wiggle your finger down into it. Then water. You'll see them perk back up (regain turgidity) within an hour or so and now you know. Apply this 'feel test' of the substrate/soil to your conifers as well. They will not tell you what is going on like deciduous trees will - it is just how they are.
 

Lorax7

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Stick a chopstick (ordinary unfinished wood one, not the fancy kind) down into the soil and let it sit there for a few minutes. Pull it out and take a look. Is the chopstick fairly wet over most of the part that was in the soil or is it just slightly damp? If it’s at least two thirds wet, don’t water it. Otherwise, water the tree. Over time, you’ll get a feel for how often each tree needs to be watered in your climate with your soil mix and accounting for seasonal changes in water demand, changes associated with pruning & repotting, etc.

Your watering habits and your soil choice should be complementary. You decide how much water is retained through your choice of soil components. Organics, akadama, and diatomaceous earth retain a significant amount of water. Lava rock, pumice, perlite, gravel, decomposed granite, etc. retain less water. The proportions of your soil mix and the tree’s water needs determine how often you need to water. If your natural tendency is to overwater, you’re going to better off with a very free-draining inorganic soil such as Boon’s mix with larger particle size. If your natural tendency is to underwater, a soil with a higher proportion of organics, akadama, or DE and small particle size will likely suit you better.
 

bonsaichile

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I water my trees daily, in the morning, and have not had an issue. I have them in purely inorganic, highly draining, substrate. As others have indicated, what kind of soil you are using is an important consideration when thinking about watering.
 

MichaelS

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I'm a newbie, and trying to understand watering my bonsai. I have 5 right now. Two junipers, a Trident Maple, Chinese Elm and a small cypress tree. I live in a hot summer humid climate, North Louisiana, USA. These trees are in the sun about 6 hrs a day. Is this enough sun? It seems that the soil is moist, even after a day or so. I don't want to over water them. The Maple is dying, or at least I think it is. It has lost all it's leaves and hasn't had any for months. Scratching the trunk with my fingernail still shows green, but I'm not feeling good about it. The soil is always moist it seems. Too moist??? Could that be the problem? Watering these trees is a challenge. Mostly because I'm a beginner, and I simply don't know what to do. Any help? suggestions? Thanks in advance.
Ideally you should not need to determine when to water. If you use the correct size pot for the root system (that is not to give too much root room and not to little - usually it's too much) and use the correct particle size for the plant (that is about 1 to 3mm for deciduous and 3 to 5 for conifers) then you should be able to freely water every day without even needing to look at the mix. It must be said though that correct watering takes a long time to figure out but sooner or later you will be able to know that the trees need watering just because you know. Generally, the longer the tree has been in the pot, the larger the tree to pot ratio and the coarser the mix, the windier the weather, the lower the humidity, the higher the temp etc, the more frequent the need for water. The opposite is also true. There is also a watering need curve which starts low in spring climbs up to it's peak in summer and then gradually comes back own in autumn. I have a wet winter so I almost never need to water then. Others might have a dry winter and need to water.
 
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TN_Jim

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Deciduous trees will loose turgidity when they are too dry - you want to water just before this happens. When the substrate/soil has run out of moisture that can be utilized by the tree, the leaves will get 'droopy'. When like this, you should note how the soil/substrate feels - wiggle your finger down into it. Then water. You'll see them perk back up (regain turgidity) within an hour or so and now you know. Apply this 'feel test' of the substrate/soil to your conifers as well. They will not tell you what is going on like deciduous trees will - it is just how they are.

I don’t think some folks understand this finger test.....
From my own experience, this advice is best for indoor plants in the way of, does the soil feel in any way remotely cold, if so..don’t water. Does it physically feel like there is water in it, may be a questionable practice for people who don’t do this much.
 

TN_Jim

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...I don’t know...this is just my experience with folks & herbaceous plants.

Is it okay to let my conifers be completely dry (white below 2”/completely dry chopstick)?...

My usual practice has been to water if the top 2” are dry even if chopstick has moisture...this has been confusing to me and I wonder if I’m watering too much....or in this case of only the top 2” dry -I should only lightly water to rehydrate the top of soil???
 

Lorax7

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...I don’t know...this is just my experience with folks & herbaceous plants.

Is it okay to let my conifers be completely dry (white below 2”/completely dry chopstick)?...

My usual practice has been to water if the top 2” are dry even if chopstick has moisture...this has been confusing to me and I wonder if I’m watering too much....or in this case of only the top 2” dry -I should only lightly water to rehydrate the top of soil???
I would water it if the top 2” is dry.
 

leatherback

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I water daily in summer. More if after a day of work the first 2 "layers" of substrate, so first 1/4 inch, are dry. Independently of species. (This is most likely why pines die after repotting in my garden). I have junipers pines olives etc in full sun all day. The deciduous temperate species are in the sun till 1 or 2 PM. So in summer that translates to 7-9hrs of sun.

I have very open substrate, 2-5mm. for all trees except some that have been recently dug / messy roots (The substrate is coarser there)
 

WNC Bonsai

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I am in a similar situation as TN_Jim. Here in the mountains we generally have fairly humid days so evapotransipiration isn’t as great as Denver, and other similar hot areas. In addition we have only exceeded 85 F a couple days this summer. This summer we also have been in a very wet, rainy cycle. Fortunately I pot up most of my trees in a well drained inorganic mix with only about 10% bark. I do have one J. maple grove in an akadama mix that stays pretty wet but the trees are still alive.

I have bamboo skewers stuck in all my pots and check them regularly. Most of my trees in bonsai pots are on a drip irrigation system and I have customized the drip rate for each. However in a couple cases (bald cypress) I do additional watering by hand to keep them really wet. When I pull the skewers I have gottent i where I can see how wet the soil is by eye. They never get completely dry as a bone but can vary anywhere from almost dripping wet after a rainy day to just a dark stain after a dry day. I even put these into some of my pre-bonsai in 3-7 gal nursery pots. Most grocery stores sell these skewers in two sizes and they are easier to use than trying to push a larger chop stick into the soil. I cut them down to about 4” for bonsai pots amd longer for deep pots. The bamboo holds up very well. Give these a try and after about a week of regular checking you’ll just get a feel for it.
 

TN_Jim

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I am in a similar situation as TN_Jim. Here in the mountains we generally have fairly humid days so evapotransipiration isn’t as great as Denver, and other similar hot areas. In addition we have only exceeded 85 F a couple days this summer. This summer we also have been in a very wet, rainy cycle. Fortunately I pot up most of my trees in a well drained inorganic mix with only about 10% bark. I do have one J. maple grove in an akadama mix that stays pretty wet but the trees are still alive.

I have bamboo skewers stuck in all my pots and check them regularly. Most of my trees in bonsai pots are on a drip irrigation system and I have customized the drip rate for each. However in a couple cases (bald cypress) I do additional watering by hand to keep them really wet. When I pull the skewers I have gottent i where I can see how wet the soil is by eye. They never get completely dry as a bone but can vary anywhere from almost dripping wet after a rainy day to just a dark stain after a dry day. I even put these into some of my pre-bonsai in 3-7 gal nursery pots. Most grocery stores sell these skewers in two sizes and they are easier to use than trying to push a larger chop stick into the soil. I cut them down to about 4” for bonsai pots amd longer for deep pots. The bamboo holds up very well. Give these a try and after about a week of regular checking you’ll just get a feel for it.

Skewers it is! This also seems a solution to feeling like I never put chopstick in same exact place, and then worrying that I am potentially damaging roots when replacing 1/4+'' chopstick into the soil..
 

Cadillactaste

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I am in a similar situation as TN_Jim. Here in the mountains we generally have fairly humid days so evapotransipiration isn’t as great as Denver, and other similar hot areas. In addition we have only exceeded 85 F a couple days this summer. This summer we also have been in a very wet, rainy cycle. Fortunately I pot up most of my trees in a well drained inorganic mix with only about 10% bark. I do have one J. maple grove in an akadama mix that stays pretty wet but the trees are still alive.

I have bamboo skewers stuck in all my pots and check them regularly. Most of my trees in bonsai pots are on a drip irrigation system and I have customized the drip rate for each. However in a couple cases (bald cypress) I do additional watering by hand to keep them really wet. When I pull the skewers I have gottent i where I can see how wet the soil is by eye. They never get completely dry as a bone but can vary anywhere from almost dripping wet after a rainy day to just a dark stain after a dry day. I even put these into some of my pre-bonsai in 3-7 gal nursery pots. Most grocery stores sell these skewers in two sizes and they are easier to use than trying to push a larger chop stick into the soil. I cut them down to about 4” for bonsai pots amd longer for deep pots. The bamboo holds up very well. Give these a try and after about a week of regular checking you’ll just get a feel for it.
Early on...I too did the chopstick trick. They are like a wick...telling you if they are moist or dry. Now...I can tell by substrate color and weight of the pot. but it really is a good method to gauge for watering.
 

WNC Bonsai

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Early on...I too did the chopstick trick. They are like a wick...telling you if they are moist or dry. Now...I can tell by substrate color and weight of the pot. but it really is a good method to gauge for watering.
My pots are wired to their monkey pole stands to prevent winds from knocking them off so lifting is not an option. Also as leatherback wrote the uppermost layer of soil may look completely dry while the lower layers are still quite wet, especially in direct sunlight or if there is a drying breeze. Sometmies I just refer back to Walter Pall’s treatise on his website that says as long as you use a modern inorganic mix it is nearly impossible to overwater (and overfeed). Right now we have had an unusually warm and dry series of days here and I feel it necessary to check the sticks mid-afternoon just in case. My drip system doesn’t come on until 5PM.
 

BrianBay9

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Early on I found that I'm way too tempted to over water, so I adjusted my soil mix to work with my behavior - watering every day. Granular, all inorganic, mostly mix of pumice and lava, sometimes with DE. The disadvantage is that trees dry out if I miss a couple of days, and they need weekly fertilization.
 

Cadillactaste

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My pots are wired to their monkey pole stands to prevent winds from knocking them off so lifting is not an option. Also as leatherback wrote the uppermost layer of soil may look completely dry while the lower layers are still quite wet, especially in direct sunlight or if there is a drying breeze. Sometmies I just refer back to Walter Pall’s treatise on his website that says as long as you use a modern inorganic mix it is nearly impossible to overwater (and overfeed). Right now we have had an unusually warm and dry series of days here and I feel it necessary to check the sticks mid-afternoon just in case. My drip system doesn’t come on until 5PM.
Walter Pall is on to something there. When I am out of the country for two weeks...I tend to have the one over water...meaning watering even if it's rained. 20 minutes on a sprinkler. They are always happy when I get home. That is only a temporary set up though...I hand water regularly when home. My trees are scattered about...and I don't wish to see the watering set up. So...I hand water.
 

LouisianaNative

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Wow, some really great info, thanks for all the responses! Someone asked what I'm using for soil. I've recently been repotting everything in Napa Floor Dry (Diatomaceous Earth). I have a little bit of dry fertilizer mixed in with it. Only 1 of my trees have been in that mix for a month or so but seems to be doing great. The Trident Maple, the one looking dead, is still planted in the original mix from Brussels Bonsai which I purchased about a year ago. It is very possible I've been over watering it. I'm considering repotting it in DE since It doesn't seem to be doing anything but dying.
 
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