It's in the greenhouse , at what temp can I put it outside. In its tub. Celsius or faranhight please. Probably spelt that wrong,
Move your Lemon Tree to the sunniest part of your home, Lemon Trees need lots of sunlight and will not flower without it.
Provide even watering.
During the winter months the Lemon Tree needs to have a bit cooler temperature-around 60 degrees F for a few hours each day through early spring.
Constant warm temperatures will keep them from flowering.
In spring you can stress the plant by stopping watering for 2 weeks, then water it twice as much as you normally would. This can often shock the tree into blooming.
Don't do this more then once, and then resume your normal watering schedule.