Q: I purchased a small tent-type greenhouse to overwinter my hibiscus and
mandevilla in. Is it better to place the plants into pots or buckets and put them
in the greenhouse tent or to actually relocate them to a single location and
replant them in the ground and then put the tent over top of them.
A: My preference would be to put the roots in the ground, either in a pot or
directly in a mound of soil. Even if it gets really cold your plants might freeze
to the soil level but won’t completely die. If your greenhouse is reasonably
tight, you can put a little electric heater inside and set its thermostat at 50°.
This is the temperature at which tropical plants begin losing leaves. Also keep
in mind that if your greenhouse is made with clear plastic, the interior will
become hot on a sunny winter day. You will run the risk of cooking your
plants. I recommend you place the greenhouse in a spot that gets early
morning sunshine but does not remain in full sun for the rest of the day.