Looking for a spot to grow seedlings while the weather is still chilly? An attic is a great place for a greenhouse because it's warm and out of the way of daily activities. Setting up a basic greenhouse is simple enough for a lay person, and you might be able to find most of the materials around the house. The only things you'll probably have to buy are shop lights and full-spectrum grow bulbs.
How to Make a Greenhouse in an Attic
Decide how to protect the floor from water --- for example, you can put down plastic sheeting or a board that has been waterproofed with a sealant.
Find a spot in your attic close to an electrical outlet, and lay down the flooring. Set up plastic or metal shelves along three sides.
Put a board across the top shelves and attach a shop light outfitted with a full-spectrum grow bulb (available online and at garden supply stores). Depending on the size of your greenhouse, you might want to install additional lights.
Plug the lights into an automatic timer and the timer into the nearby electrical outlet.
Cover your greenhouse with plastic sheeting to retain even temperature and humidity levels. Cut a flap to make an entrance.