keep moist, don't overwater?

[63pmp]

"keep the soil moist, don't allow it to get too wet."

I read this so often on bonsai posts all over the world.

For the life of me I cannot see how one can water effectively and not have a saturated medium afterwards. How can anyone only water to keep the soil moist?

If you water a bonsai, the potting media fills with water and any excess that can't be retained by the mix drains out the bottom. You can tilt the pot 45-90 degrees and a little more water will drain out. If you have fine potting media it will hold a lot more water then a course potting medium, but it will always be at the maximum moisture content after draining, which is never moist. Moist is something you get after some of the water has been taken up by the plant, which usually depending on weather and temperature, occurs an hour, or perhaps, days later.

Could someone please explain to me how to water so that the soil remains moist, not wet?

Sorry for the rant, but I see this said so often to people with sick plants and it is arguably the most useless piece of information handed out on forums.

Paul

[Eusto]

I'm pretty sure it means, water the bonsai, then don't water again until the moisture is starting to dry up. As in, don't let the soil dry out completely before watering, and don't water again while it is "wet".
I find a good rule of thumb is to not water the bonsai if the top inch or so of soil is still moist.

[Rory]

The science of watering container potted plants, whether they are bonsai or not is essentially not something you can learn on a forum. Go to a nursery, and ask them to show you when is a good example of a potted tree that needs watering. This is the best advice you can give anyone, as you will see first hand what is required. Are you asking for yourself, or just in general, as with your bonsai age there, I am guessing you mean in general. You are not meant to keep the soil moist.

Step 1. Water bonsai thoroughly, and allow all the excess water to run free.
Step 2. Do not re water the bonsai until the soil is just about dry. (This can vary for your different types of trees, as some will use the water faster than others, so you cannot have a system of watering that is the same for all your bonsai. Hence, the horrible downside of owning bonsai. But apply Step 2 for all your bonsai. Otherwise, if you are just rewatering all of them when you think the majority of them need more water, then chances are that you have too many bonsai to look after.

Repeat steps 1 & 2 until you are due to enter a nursing home. In which case, step 3 is required, which you wont remember anyway, because you'll be old and senile.

[DustyRusty]

Personally I believe it is good advice for a very poor, fine, water logging mix. And therefore good advice for those with their first bonsai bought from the big green shed. It's bad advice for a good, course substrate mix in which you can water all you like and the tree will be fine. How you do it, I don't know, water with a little bit of water, or water every 3 days depending on the season. If you have a clay like mix and water your mallsai aggressively every day that tree will be in trouble.

[bodhidharma]

Sorry for the rant, but I see this said so often to people with sick plants and it is arguably the most useless piece of information handed out on forums.

I totally agree with you Paul. This is up there with someone who has a little mister and "mists" there Bonsai.

[longd_au]

I am sure there are very qualified people in this forum who can answer this question way better than I do.
But I think the true answer between two wet pots with different soil mix lies in the oxygen content and it's ability to exchange gas.

An open mix will look wet, act wet but will have larger oxygen pockets, hence more oxygen,better air flow and dry faster. It will also have better capillary activity compared to a compact mix such as clay. But yes, clay will dry in time too.
No oxygen, things die.

[kcpoole]

The science of watering container potted plants, whether they are bonsai or not is essentially not something you can learn on a forum. Go to a nursery, and ask them to show you when is a good example of a potted tree that needs watering. This is the best advice you can give anyone, as you will see first hand what is required. Are you asking for yourself, or just in general, as with your bonsai age there, I am guessing you mean in general. You are not meant to keep the soil moist.

Step 1. Water bonsai thoroughly, and allow all the excess water to run free.
Step 2. Do not re water the bonsai until the soil is just about dry. (This can vary for your different types of trees, as some will use the water faster than others, so you cannot have a system of watering that is the same for all your bonsai. Hence, the horrible downside of owning bonsai. But apply Step 2 for all your bonsai. Otherwise, if you are just rewatering all of them when you think the majority of them need more water, then chances are that you have too many bonsai to look after.

Repeat steps 1 & 2 until you are due to enter a nursing home. In which case, step 3 is required, which you wont remember anyway, because you'll be old and senile.

Gold post this

to learn how dry the soil is is the art. The top 10mm is not really and indicator so you need to check 25 - 50 mm down in the pot to get a good idea.
Push a Bamboo chopstick into the soil and leave for a few minutes, when it comes out check is it moist? if so do not water, if not them water well until it runs out of the bottom.

Use finger is an alternative or just plain old dig and see.
use a marker plant that droops foliage when it gets dry, make sure this one dries faster than your important trees

Ken

[Grant Bowie]

My best tree; my Banksia integrifolia; is also my water weed.

It will always need watering before everything else so you know you don't need to water everything if the Banksia is OK.

Grant

[Jason]

I've read and heard many times that watering is one of the hardest parts of the art to master, and am slowly understanding why.

I know what is meant by 'moist and not wet', but actually achieving that is still something I'm working on especially when each plant is different

[Josh]

This is where hand watering and knowing your trees. Like you Grant I have a couple of trees through my trees which dry quicker and they are my indicators. If they are dry I water. I also have a couple of trees that are in older mix (haven't changed over yet) which stay wet longer so always check before watering.
What I hate is when your trees NEED watering but rain is forecast later in the day. You are going to be out all day, do you water or hope it rains. If I don't water the rain never comes, if I water it pours down all day
I think at the of the day each person needs to work out what works for them as everyone's mix is different. Bonsai aren't really any different to other potted plants. To much will kill them, not enough will kill them, to much TLC will kill them

Josh.

[ozzy]

In Summer I have been known to leave plants standing in tubs of water for over a week or more with no ill effect, you cannot overwater a plant if you have a free draining mix.

[Boics]

Yes.

Interesting topic.
Completely understand that the most optimum conditions are to saturate with water let nature and the elements dry the pot (not completely) and repeat.

Really though.
What is the difference between say letting a pot dry 75% on average before watering (which i would assume to be near to optimal) and only letting a pot dry 25% (therfore being fat more wet)?

Nb. comment is regarding a well draining open mix (which I would assume most here use).

Cause like Ozzy I find that watering too little is far riskier than watering too much!

My point is........ Am I really jeopardizing significant growth/health by keeping my trees more moist than dry???

[k2bonsai]

ok i will try to keep this as short and simple as possible as i am trying to type all this on an ipad.

In your soil structure you have macro pores (these predomantely hold air after gravitational water exits the soil) and micro pores (these hold the capillery water which is available to plants). This is whee your agreegate mix comes in, if you have large aggregate then that will allow for more macro pores and this more air (also better drainage). If you have a really fine soil Aggregate then you will have less macro pore space, hence less air space. Then comes the mineral material itself. Clay soils have many many micropores internally which swell and hold lts of water, plus the colloids allow water to cling to the outside of the particles. Sand will have less micropores, whereas something like pumus has more etc. vermiculite basically acts very much like clay.

When you fill a pot with water to the point of saturation plus more, the water that drains from the soil is called gravitational water and is not used h the plant. when this gravitaional water exits the macro pore spaces are replaced by air. your micropores now hold the capillery water which is the only water avilable to plants. if your soil is not free draining you have the situation whereby air is not getting back to the roots to breathe. There is also another thing called hygroscopic water which is water that is overly sticky to the mix and also is not available to plants.

capillery water id drawn up by moving from wet soil to dry soil. the ideal mix is simply one which if free draining to remove thengravitational water quickly and replace it with fresh air, whilst retaining enough caplillery water to satisfy your plants until the next watering. however, courser more open mixes have less ability to retain nutrients, whereby finer spils and clays are much better at holding nutrients.

when feeding your plant, for a higher agg mix (sandier mix) you feed ata lower concentration of frertolizer but more frequently (weekly). When you have finer particles with more clay content or clay immitation products, then you feed at stronger rates but less often (fortnghtly or longer).

I could keep going but maybe i might do a weekly quick guide for soil study if people would find this useful? also once i return from my trip away this week and can use a normal keyboard

sorry for all the typos.... big fingers

[k2bonsai]

by the way, do not put larger particles at the bottom of your pot and finer mix on top UNLESS you want your finer soil layer to hold extra water as you are basically creating a perched water table.

[Reece]

ok i will try to keep this as short and simple as possible as i am trying to type all this on an ipad.

In your soil structure you have macro pores (these predomantely hold air after gravitational water exits the soil) and micro pores (these hold the capillery water which is available to plants). This is whee your agreegate mix comes in, if you have large aggregate then that will allow for more macro pores and this more air (also better drainage). If you have a really fine soil Aggregate then you will have less macro pore space, hence less air space. Then comes the mineral material itself. Clay soils have many many micropores internally which swell and hold lts of water, plus the colloids allow water to cling to the outside of the particles. Sand will have less micropores, whereas something like pumus has more etc. vermiculite basically acts very much like clay.

When you fill a pot with water to the point of saturation plus more, the water that drains from the soil is called gravitational water and is not used h the plant. when this gravitaional water exits the macro pore spaces are replaced by air. your micropores now hold the capillery water which is the only water avilable to plants. if your soil is not free draining you have the situation whereby air is not getting back to the roots to breathe. There is also another thing called hygroscopic water which is water that is overly sticky to the mix and also is not available to plants.

capillery water id drawn up by moving from wet soil to dry soil. the ideal mix is simply one which if free draining to remove thengravitational water quickly and replace it with fresh air, whilst retaining enough caplillery water to satisfy your plants until the next watering. however, courser more open mixes have less ability to retain nutrients, whereby finer spils and clays are much better at holding nutrients.

when feeding your plant, for a higher agg mix (sandier mix) you feed ata lower concentration of frertolizer but more frequently (weekly). When you have finer particles with more clay content or clay immitation products, then you feed at stronger rates but less often (fortnghtly or longer).

I could keep going but maybe i might do a weekly quick guide for soil study if people would find this useful? also once i return from my trip away this week and can use a normal keyboard

sorry for all the typos.... big fingers

Nice explanation! Its pretty logical if you have that sort of brain......