AusBonsai

I'm looking at planting a few of my trees on a CD or a tile in order to get a better root spread while in there training pot.
Just wondering how deep below the top of the soil line do I place the tile?
Thanks.

Hi zero,
Depending on the size of the trees/trunks? I plant some pencil thick maples on plastic party plates at about 20-25 mm deep because the plates side sloped the roots sloped down nicely. Hope this is helpful.
Cheers Rod

I put mine on CD's and probably only 2cm's worth of soil on top of it. You can only put so much, as otherwise you'll be covering the trunk in soil, so you can just judge it by that

Maybe I have a bit more experience with this? I would not bother planting on a CD. Every time I have used things that are softer or brittle I found that the roots just crushed and broke it so no advantage. A ceramic tile might survive - depending on how long the roots are allowed to grow for but the pressure exerted by thickening roots is enormous - think about street trees cracking concrete and garden trees that move house foundations.

I currently use aluminium sheet sourced from old road signs from scrapyard and cut into 7-10 cm squares. Most of mine are planted with the seedling threaded through holes drilled in the plates. As the seedlings thicken the metal cuts off circulation and the trunk puts out new roots just above thee metal - all horizontal and mostly all around the trunk.
Must be planted only a few cm deep or the trunk will put our roots at all levels wherever it is under the soil (tridents more so than others) which spoils the whole point of the excercise.

Have fun with whatever method you use and let us know how it goes.

My experience with planting a seedling in the middle of a drilled tile/CD is that you must be mindful of the difference in environment to the plant above and below the tile/CD.
My observation is that the part above the tile can dry out a lot faster than the part below. If planted in soil that stays wet longer, this can result in the part below the tile staying wet too long and resulting in root rot.
I find this less of a problem if the seedling is a bit older e.g. 1-2 yrs old.

Otherwise, this is a wonderful technique and I thank Shibui (Neil) for educating me and showing me the result it can achieve.

shibui wrote:Maybe I have a bit more experience with this? I would not bother planting on a CD. Every time I have used things that are softer or brittle I found that the roots just crushed and broke it so no advantage. A ceramic tile might survive - depending on how long the roots are allowed to grow for but the pressure exerted by thickening roots is enormous - think about street trees cracking concrete and garden trees that move house foundations.

Thanks Shibui! I've just started using them.... but will now upgrade to something better with that advice Was all I had laying around, and they weren't getting used for anything else

I have used CD's for Ficus seedlings and have never had issue with the CD breaking up, for any reason. I have only used them for the tree's first year of life and the trees were always planted on top of tiles for the second and subsequent years of growth. I have also used squares of lino instead of tiles as well, which worked just as well. As Shibui said, stick the seeding/cutting up through the hole and in time the tree will issue a new set of horizontal roots out around the CD. Come re-pot time simply cut the trunk off directly under the CD and plant on normally. Using this method I have found very few crossing roots amongst the new root system for some reason either.

Thanks for all the advice guys.
I will give it a go.

I currently have a number of trees planted on CD's including privet, banksia, Buxus and others. I'll let you know how they go when I repot them. The privet have the CD screwed to the bottom of the tree.