To help your plants and seedlings thrive, your greenhouse should be placed in a space with plenty of natural light. Full sun is ideal, but it will depend on the layout and landscape of your garden.
Yes, you can still use a greenhouse throughout the winter months. Whether you're storing tender perennials or growing fresh seeds for the upcoming year, they'll thrive with protection from the rain, wind, frost and snow.
You'll want to open all the windows, doors, and vents on sunny days in your greenhouse. But if the temperature remains high, prop the door open overnight as well. You could even install an automatic vent opener.
Overall, plastic greenhouses tend to give a better experience. This is because glass greenhouses are more expensive, and plastic (specifically polycarbonate) retains heat better than glass.
If you plan to grow plants or seedlings in your greenhouse over winter or spring, you may need to warm your greenhouse to start the germination process. This could be done with a solar heater, composting manure, bubble wrap or horticultural fleece.
The best place for a greenhouse is any location that gets full sun between winter and spring. This is usually the south or southeast side of a garden.