How to Set Up a Greenhouse and Flooring Options
Learn the essentials of greenhouse flooring, climate control and set up.

Greenhouse specialist Scott Naegeli suggests the best ways to floor, heat and furnish a greenhouse:
Greenhouse floors need to have excellent drainage. Floors can be made of concrete, stone slabs, brick, sand or even dirt. Gravel floors provide excellent drainage and can be used in conjunction with a weed barrier to keep weeds from growing up through the rocks.
Heating and Cooling a Greenhouse
Gas heat is more expensive to hook up initially, but in the long run it's more economical. A heater is especially important in colder zones, where a greenhouse may be heated for months at a time. A greenhouse needs to maintain a minimum temperature of 55 degrees for most plants.
Keeping your greenhouse cool is just as important as keeping it warm. If it gets too hot, the plants will suffer. This greenhouse uses an evaporative cooling system to keep temperatures down. It also helps keep inside air circulating: a key ingredient for healthy plants. Vents in the ceiling let hot air out when the temperature rises.
Plant Stands and Work Areas
Staging areas are important in the greenhouse. These are places where tables and benches are set up to act as plant stands or work areas for potting plants, filling flats, etc. Staging areas give you more usable space.
Freestanding sheliving units are made from durable plastic and fiberglass, materials that are rust- and warp-proof. When setting up a freestanding area, leave a generous gap between the back of the shelving and the side of the greenhouse to allow for air circulation. Freestanding units are best because they can be moved around to accommodate different plants in different seasons and removed from the greenhouse when not in use.
In a greenhouse, using every inch of space is essential. A 12' x 12' greenhouse is fairly large, but it will quickly fill up once you add plants, shelving, lights and other accessories. The walls in this greenhouse are clear from floor to ceiling, letting light in on all levels, including the floor. You can also use otherwise empty ceiling space by hanging baskets.
To start new plants from seed, you can set up a propagation area. Naegeli suggests using a germination mat because it heats the bottom of a seed tray and thereby stimulates growth. Seeds need more warmth than other plants in the greenhouse, so this is a very localized way to heat one area of the greenhouse without raising the entire greenhouse temperature.