Generally this involves withholding food for 3-4 weeks before hibernation whilst still providing a water source. This can be done by bathing the tortoise daily for 20 minutes in a warm bath. The tortoise should be kept warm for the first week & then at room temperature for the following 2-3 weeks prior to hibernation. A full bladder can make up 25% of the total weight of a tortoise so a well hydrated tortoise with a full bladder will weigh significantly more and this should be monitored carefully before hibernation.
If your tortoise is in good body condition you can proceed with hibernation. Hibernation temperature should be between 2-8°C. Any lower than this and frost damage may be a problem. Any higher and the tortoise’s metabolism will increase and it will start to move. Tortoises can be kept in an outbuilding in an insulated box (inside another insulated box).
If there is any chance that rodents could get to the tortoise or if the temperature cannot be monitored carefully then it is better to use a fridge or chiller cabinet to maintain a temperature of around 5°C. You should also be careful to maintain humidity and this can be achieved by placing a small bowl of water in the fridge to prevent dehydration. Frost damage and rat bites are quite common hibernation problems and therefore hibernating your tortoise in the garden is not advisable.
Hibernation usually will be for approximately 3 months but can be reduced if the tortoise loses more than 1% of its body weight per month. The tortoise’s bladder acts as a water store so if the tortoise urinates, it should be woken from hibernation.
Ideally the tortoise should be kept at room temperature for a few hours prior to providing supplemental heat and a warm bath. Bathing should be performed daily until the tortoise is active, eating and urinating. Tortoises should have a focal hot spot of 40°C as they are basking animals. This can be provided by an overhead spot bulb but a thermostically controlled heat source may be required. If they do not have this then their body temperature will remain low and they will not start to eat. Overnight temperatures should not drop below room temperature.
Good food sources include green leafy vegetables such as kale, spinach, broccoli, cabbage, bok choi, endive, mange tout, spring green, brussel sprouts, grated carrot, and even better are naturally grown weeds such as dandelion grass, chickweed, milk thistle, sedum, honeysuckle, nasturtium or hibiscus flowers or wild pansy.