Weird question probably but i have always had an obsession with creating my own jungle style greenhouse, koi pond included and possible semi free range guinea pig included. I have worked out more or less the cost and design of the green house. now comes the next part, the problems, mildew, rot, mold, rats and of course the dreaded insects. Ventilation should solve most of the problems with a little added care. but what about the insects, in a contained enviroment it might make it harder for the bugs to get in, but when they are it will be harder (and less inclined) to get out again. so obviously i will have to invest in some ladybirds or similar predators. what i am wondering is if it would be possible to put in only one population of ladybirds that will maintain a constant population and will control the pest problem that will not all fly off should i open the door to cool the greenhouse. I would like the greenhouse to run itself really, i would only have to intervene to do the odd bit of weeding and trimming. has anyone managed this? any thoughts welcome. Also the guinea pigs was an after thought as i think (providing the small vunurable parts of the plants are out of reach) it would have a fun time in a large run (big greenhouse) adding some fertilizer and possibly help out with the weeds. do people think this could be a good idea?