Six Considerations for Choosing a Hobby Greenhouse

By: Roger Hintze

Thinking of purchasing a hobby greenhouse? Here are a few things to consider before you take the leap.

Are you going to be using the house the year around, and in what type of climate? The reason for this is to know the R value (insulation) of the material that covers the house. If it is really thin and the winter temperature is going to fall below freezing or more you might want to consider what it's going to cost to heat the house. Some of the choices available include glass, single wall polycarbonate or twin or triple wall polycarbonate. The multi-layer polycarbonates are the better choice for northern climates.

Where are you going to place the house? Is it in an area that receives adequate sunlight? Many of the flowering plants require at least six hours of sunlight per day. If you place the house too close to the north side of a building or other stable object remember that the angle of the sun will decrease as the season moves toward December and shadows will become longer. Think ahead as to where you want the entrance door to face. If you are planning on operating the house during the winter you may not want to place the entrance door on the north side. Houses generally are placed with the length oriented in an east-west fashion. This takes advantage of the low angle of the sun in the winter.

Are you going to need a building permit from your local government? Check with your city or county offices for existing building codes.

Heating and ventilation considerations are important. If you will be installing a heating system you will need to decide on your source of energy -natural gas, LP gas, electric or fuel oil. You will need to size the heater, which is calculated according to the type of your house covering and the extreme external temperatures encountered during the heating season. As for ventilation, moving the air within the house is usually not enough. You will need a wall mounted fan that pulls in fresh air from the outside and an opposite mounted fan to exhaust the hot air to the outside. Another choice would be movable roof vents, which can be thermostatically opened when the temperature reaches a pre-determined level. Fans will also need to be sized according to the amount of the air volume in the house.
Foundations. Houses will need to be secured to the ground so that they don't blow away in windy weather. There are several choices to do this. Foundations can be made by pouring a cement slab, driving anchor stakes into the ground or attaching the house to a wood beam base.

Additional considerations. If you are installing heating and/or ventilation, supplemental lighting or devices for adding humidity you will need to run electrical power to the house. If you are operating the house the year around and don't want to physically carry pails of water you will want to install a pressurized water source. In areas where it doesn't freeze you can run surface pipes or hoses from a main source of water. Unless you are growing plants in the ground there will be a need for some form of benches on which to place your plants. In order to cut down on the intense summer sun you have a couple of choices-woven shade cloth made with various percentages of shade or liquid reflective shade compound that can be sprayed onto the roof. Finally, there will be a need for plant containers, soil mixes and fertilizers. And, you will need a source for seeds and living plant material. Be informed too, that you will never have enough space. Consider purchasing a house for which there are available incremental additions that can added to your existing space.

Roger Hintze has BS and MS degrees in Ornamental Horticulture from the University of Minnesota and has been employed by J R Johnson Supply for 40 years. J.R. Johnson Supply headquartered in Roseville, Minnesota is a horticulture supplier and has over 30,000 items available in its on-line store. Specialties include soil media, containers, pesticides, fertilizers, irrigation equipment, nursery supplies, greenhouse supplies, organic growing supplies, generic chemicals, and landscape or retail garden center supplies. In additional to hobby greenhouses, Jr Johnson is selling a number of products for the garden hobbiest, including raised garden beds, backyard compost bins, compost aerators, rain barrels and compost tea brewers