I hope you might be able to give us some advice. We have 4 one year old greek tortoises and want to start making an outdoor enclosure. We've had them a month or so and so far, it's been too cold here in Germany.

We are thinking about making the size 480cm x 250 cm, 12sqm. Is this big enough even when they reach adulthood? Stone and brick boundaries seem very expensive here so we thought to use wood planking for the boundaries. About 4 cm high with an overhang to prevent escape. Is cold frame sufficient inside the enclosure or do they also need a more wooden house? How far down do we have to protect from digging escape? What kind of wood is most suitable. I'm not sure if we would be able to determine if wood is chemically treated. Is there any kind of treatment that would be bad for tortoises? What's the best kind of treatment to apply to plain wood?

So sorry for all the questions, I've googled myself silly and can piece the answers together.

Many thanks in anticipation

As you've waited 4 days, I'll have a go.12sqm is good, cover with netting at that age. I suggest "gravel board" 15cmX2cm approx. In yr 4 or 5 (you will know) add another plank making it 30cm high. G.B. is pressure treated, leave outside for a week to 'weather'. They don't dig to escape, but make sure there's no dips. Wooden house with poly carbonate roof is best.
When they're 12cm in L. double the area to at least 24sqm.
Regards
Tom