How to Build a Mini Greenhouse for Growing Sprouts and Wheatgrass
By Brian Hetrich Greenhouse Manager
Many people are interested in growing wheatgrass and sprouts and other plants in a greenhouse at their homes. You can grow an abundance of food in a relatively small 10’ X 10’ mini-greenhouse. The primary consideration is that sprouts and wheatgrass need to grow in a climate controlled environment. A pre-constructed shed with windows on all four sides is an ideal starting point. Here is the plan:
1. Purchase a prefabricated 10’ X 10’ shed like the one pictured below. Have it delivered and installed in your back yard. Specify you want windows on all four sides and in the door. The porch is a nice touch but optional. Of course, you could always build your own from scratch or hire a contractor to do the work. Depending upon where you live you may need to get a permit from your county government and permission from your Home Owner’s Association.
2. Have an electrician run 30 amp service to the shed sufficient to power the lights and air conditioner.
3. Install a packaged Terminal Air Conditioning (PTAC) unit through the wall. This type of air conditioner is capable of both heating and cooling with automatic changeover. Ideally, the temperature should be kept between 65-75 degrees Fahrenheit and the humidity less than 50%. Keep the circulator fan programmed to run continuously.
4. Have a plumber run a ½’ cold water supply pipe to the shed and install a hose bib inside. Make sure the pipe is properly buried and insulated to protect against freezing.
5. Install several drain holes in the floor.
6. Install artificial light and use full spectrum bulbs. LED lighting is an excellent choice from an energy conservation point of view. Plus, unlike fluorescent bulbs there is no mercury in LED lights. You will need enough to give 1,200 foot-candles of light. This is the same as 1200 lumens one foot away from the top of the sprouts. This will require about eight 60-watt equivalent light bulbs. Plan on keeping the lights on 12 hours a day and turn them off at night. You can use an automatic timer for this function.
7. You will need to insulate the walls and ceiling so your utility bills will not be too high and you will be able to maintain the correct temperature and humidity. Insulate the walls floor and ceiling with a minimum of R-12 insulation.
8. Install drywall on all the walls and the ceiling. Use green board drywall to inhibit rot.
9. Tile the floor and walls up to the ceiling like the inside of a shower. Paint the ceiling with no-VOC paint.
10. Install a sound system so you can play classical music to your plants eight to twelve hours a day!
In this configuration you can easily fit up to 168 small trays for sprouts and wheatgrass if you use 24 of the 7-tiered small Hydrosol racks. These racks can be ordered from the Hippocrates store (which can be shipped to you) or you can build you own. Happy sprouting!