How to Build A Commercial Backyard Greenhouse

Building a commercial greenhouse on your personal property is major undertaking. Budget for site leveling, foundation rock, and lots of lumber for your end walls & sill. The actual greenhouse structure is a very small part of the total investment. We will discuss construction of greenhouse cold frame structures only.

Instructions

Difficulty: Challenging

Things You’ll Need:

• Greenhouse
• Treated Lumber
• Greenhouse Poly Film
• Shadecloth
• Exhaust Fans
• Power Tools
• Friends to Help
• Plumbing pipe & Electric Wire
• Water shutoffs & backflow devices

1. Always Call Before You Dig Foundation Work: Depending upon your site location, a minimum of 4" of 5/8" gravel for drainage is suggested. Trench out areas for your pipes for plumbing as well as electricity. If the greenhouse is heated, trench for your propane or natural gas line. Ask your gas companies for legal safe distances of the propane tank from your greenhouse. Many existing lines are buried only inches from the surface. ALWAYS CALL BEFORE YOU DIG!
2. Inside a Semi-Quonset Style Greenhouse Choosing Your Greenhouse Structure: Pick a quonset or semi-quonset style.Typical greenhouse dimensions are 20'x 96' or 30' x96'. The semi quonset style generally has a 3'-5' sidewall, adding head room for benches. Depending on your climate, you may need a structure built for snow. Placing your greenhouse bows on 4' centers will help protect the house from collapse due to snow or ice.Concrete each bow into the ground for more strength. A minimum of 3 purlins are needed - the pipe running the length of the greenhouse for structural support.Finally, each greenhouse corner has a bent pipe for load bearing.
3. Greenhouse Construction Party- Grab a Power Tool! Building: Once the greenhouse bows are up, the house comes together quickly. Invite friends with cordless drills and screwdrivers to join you for construction day(s). Attach your pressure treated wood sill (2" x 6") to the entire perimeter of the greenhouse. This is the base to hold your greenhouse film and shade cloth.Build your endwalls, allowing for a door on each end for ventilation.Frame in your exhaust fans & build a support frame if using a heater using your work party to help.
4. Doublecheck Valve Back Flow Preventer Plumbing & Electrical:
   For watering your plants,you need piping in the greenhouse . Many parts of the country require backflow preventers for environmental water safety. To use exhaust fans,you need wiring and a power panel . Also, allow at least two waterproof light fixtures for those inevitable trips to the greenhouse when the sun goes down. One additional outlet for power tools is a smart idea.
5. Greenhouse Poly Film Can Last 4 years or Longer Covering the Greenhouse:Choose greenhouse film based on your climate & budget.Think green - buy the film with the longest life & find out where you can recycle it.Consult with a commercial horticultural distributor for advice on film & locking devices to securely hold the plastic.Order a shadecloth to spread over your house to reduce heat & plant scorching.
6. Wood Greenhouse Benches Inside the Greenhouse:
   If this is your only greenhouse, use part of the space for a potting bench with inside space to store soil. A 4' x 8' plywood table for potting will give you plenty of room. Store your soil on raised pallets to keep it dry.Create wide enough aisles to walk through & drag hoses if you do not have overhead irrigation.
7. Your Greenhouse Garden Gnome is Watching.. Enjoy & Good Luck!

Tips & Warnings

• Congratulations, you now own a plant factory capable of making you income !
• You have a 24/7 live obligation
• If you are leaving town for a day or longer, assign a responsible family member to check the greenhouse for watering, ventilation & any stray deer or critters deciding to dine on your crops
• Please, talk to professional greenhouse growers before you purchase the greenhouse
• There is no "auto pilot" on a commercial greenhouse