As long as there are no pesticides or other toxic chemicals, any soil is safe to grow their food in. Fertilizers are fine in the soil, and also necessary for the plants, as long as the tortoise does not have direct access to the fertilizer product. I use a variety of bagged soil in raised planter beds and pots to grow tortoise food. I just don't let the tortoises have access to that soil.What soil is safe for me to grow my tort some greens in?