Hello and welcome to FF! Estivation is not triggered by cold like hibernation, but by a cooler dry season: http://www.frogforum.net/general-dis...ion-oh-my.html. A fan that cools the terrarium from outside might help a bit; but you would have to keep close monitoring on the humidity so it does not drop too low.

Recommend try to work around problem and schedule your "dry" season when your local weather is the coldest and days are shorter. Know some breeders trigger spawning with hormone injections; but have no idea what is involved in process. Maybe Colleen/Jerrod have better ideas and will post soon.

Sorry your Mom does not let the frog in, we usually keep ours inside in USA. Mine are in kitchen and living area and their earthworms are kept in the veggie bin beside potatoes, carrots and onions I eat. Think need adult supervision at home .