Larger Potted Trees - Don't seem to need watering...ever.

[edro]

Most of my trees are shohin sized and all have very coarse soil mixtures.
They use water "normally" depending on the season and temperature.

I have a few large junipers in ~2ft cubed grow boxes that never seem to dry out.
They were nursery potted (dense potting soil).
Last year I raked the roots, cut off 1/3 of the root mass and repotted them into the grow boxes.
The soil mixture is 1/5 Turface, granite grit, haydite, pine bark, potting soil.
I used the potting soil component just to retain a little more water.

Anyway... I never have to water these trees.
The soil ~2" down in the pot is always semi-moist.
The trees seem healthy and a growing fine.
They get a few hours a direct sunlight a day, the rest is indirect.

Do larger potted trees need less watering?
Do you ever go weeks on end before needing to water them?

 

[DaveV]

Edro. The fact that they are growing means don't worry too much about that. With the ingredients that you listed, I would think that the soil would stay moist for a while. I would place a chop stick in the soil and check the moisture level that way. Make sure not to over water.

Dave V.

 

[mcpesq817]

Be a little careful when dealing with species that like it on the drier side. I killed a scots pine by up-potting probably a little too much. Autopsy results showed that the soil mass was really wet right under the root ball, despite it being dry on the surface.

 

[Bill S]

Sounds like you are talking about larger pots not larger potted trees. 2 cu ft of soil is not a small amount, smaller trees won't fill and use that much for quite some time. May want to consider it over potted.

There are some articles(maybe someone can point them out, no time now), about size and shapes of containers and how they work, it's amazing how just the shape of the container can make a difference. For instance a tall cascade pot drying quicker than a flat rectangular pot. Has some good info to consider, when you are determining what to plant your trees in. At least one of the articles is the earth is not a pot, or something close to that.

 

[misfit11]

At least one of the articles is the earth is not a pot, or something close to that.

It's titled "Why the Earth is Not Like a Pot". It was written by Brent Walston of Evergreen Gardenworks. Definitely a good article.

http://www.evergreengardenworks.com/earthpot.htm

Peace

 

[Bill S]

Thats definately one of the good ones, I think it's the one where they describe using a sponge at different positions to see how it drains, to help get the idea across.

 

[rockm]

Your problem is with your soil. Potting soil is an extremely poor choice to use in bonsai soil, or any tree (or perennial plant) in any container. Potting soil engineered to do exactly the opposite of what bonsai soil is supposed to do. It holds onto more water for longer than it should. It's also finer particles clog the drainage that's needed for bonsai or woody plants in containers. It rots roots in prolonged contact with it.

The large volume of soil you're using only multiplies that effect. Larger masses are less prone to change. A large soil mass takes longer to dry out than a smaller one. This is true even with bonsai soil. I have an oak in bonsai pot that holds roughly five or six gallons of bonsai soil. Sometimes, depending on season and weather, it requires watering every three or four days. Sometimes, it needs watering once a day...