Simple question, how much (if any) soil is needed between the grass mat and the fleece barrier?

I'm building an enclosure for my tortoise and I want to place grass on trays for it to roam. The trays are 8 cm depth (3 in), I will have a bed of expanded clay with a fleece barrier on top for drainage that takes about 3 cm (1 in) leaving 5 cm (2 in) for the soil + grass. Is it enough?

How thick are grass mats? How much soil is needed? I plan on using Zoysia Emerald grass (it is short and readly available here).

1 Answer 1


Depends what you mean as far as "grass mats".

If you mean artificial grass mats then soil depth doesn't matter.

If you mean mats that have seeds in them that you lay on soil to grow, or pregrown rolls of sod then the grass needs the same amount of soil depth as grass or installed with other methods. Minimum is about 3-4" of good topsoil but roots tend to grow deeper into the subsoil. Zoysia supposedly has a very deep root system that can grow up to 2 feet deep.

If the soil is shallow you'll have a hard time keeping the grass alive. You'll probably have to water it daily.

  • I meant rolls of sod (I didn't know the english expression for it). This settles my question, I will just use regular substrate for the tortoise, the grass wouldn't survive with just 2 inches of soil. May 1, 2014 at 17:25

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