Author Topic: Construction gravel for use in soil mix or drainage layer?  (Read 2638 times)

jtucker

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Hi All,

I was over at my uncle's and saw a bag of 3/8 inch gravel that he was using for a concrete/paver project. I checked it out at my local home improvement store and it sells for like $3.50 for a 50 lb. bag. Anyone use this for a bottom drainage layer or even in their soil mix? Any opinions yes or no?

Jason
 

Chrisl

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Re: Construction gravel for use in soil mix or drainage layer?
« Reply #1 on: August 28, 2011, 12:01 PM »
I'm not a soil expert Jason, but I'd say no.  I've seen nobody mentioning using gravel in their soils.  People I've seen who are trying to save money uses say, diatomaceous earth, turface mvp, hyalite and/or lava.  And 3/8" is too large, try to use b/w 1/8" to 1/4".  These are just some guidelines I've picked up surfing about soil.
Good Luck.
 

Josh

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Re: Construction gravel for use in soil mix or drainage layer?
« Reply #2 on: August 28, 2011, 01:10 PM »
Jason,

The experts would say not to use, especially if you have shallow pots appropriately sized for a finished tree.

I can tell you that I have used nursery gravel with no problems, for trees in development which you may be overpotting.  It often is dirty, I place in pot, give it a good wash first.  Then place a layer of your more conventional "bonsai soil" mix on top to rest your roots.

As an aside, I have read some interesting articles on root development, in which I find the cheap gravel very handy for immature tree (and root) development.  Most nursery pots are too deep (for their width).  I have purchased larger nursery pots, placed a smaller pot inside (upside down) which gives you a more shallow space for roots to grow horizontally.  I place a layer of gravel along the sides of the smaller pot, cover the sides and the small pot with bonsai soil and place the tree you want to beef up on top of this.

Let is grow for a couple of years.  When you repot this tree in the future, you will find roots growing horizontally across the smaller pot, and down the sides.  It is a pretty easy transition to finished pot. 

Good luck, Josh