Sure, you enjoy outdoor gardening, but the controlled environment of a greenhouse can create a lush sanctuary to enjoy year-round—from starting seeds earlier in the winter to extending the growing season into the fall. From large freestanding buildings to small window-mounted structures, a greenhouse is possible for almost any gardener!
What is a greenhouse?
A greenhouse is a structure enclosed by glass, plastic, or other transparent or translucent material used for the cultivating and protecting plants. For centuries, gardeners have used greenhouses to capture the light of the sun during the day and protect plants from lower night temperatures.
If you are thinking about adding a greenhouse consider:
Type of structure/material
Constructing your own small greenhouse of scrap materials may be almost free, but ready- made or custom-made greenhouses can be costly. Consider type, size, material, and features in planning to meet your budget.
Important factors in locating your structure include:
– Year-round access 6 to 8 hours of sun—away from evergreen trees or sun-blocking structures
– East to west orientation
– Near a water source and electricity
– Fans and ventilation encourage peak photosynthesis that provide plants with a constant air supply.
– A heating system is necessary to use a greenhouse year-round.
– Air vents and either glazing or shade cloth are also necessary to prevent over-heating. Adequate drainage is important—consider gravel over landscaping cloth or a floor drain.
– Some greenhouse owners add a mist system
– Most have a potting bench and shelves.
For 19 years, in my own 12 X 24 glass greenhouse, I have used a wall-mounted oscillating fan and a small space heater to prevent freezing of overwintering plants.
Types of greenhouses
o Permanent structures—may last for 40 to 50 years add value to your property.
o They transmit the most light and are valued for their beautiful appearance.
o Treated with UV protectant to prevent yellowing or deterioration. Very durable—usually last about 10 years.
o Polycarbonate helps diffuse light more evenly than glass, helps plants grow faster, and provides better insulating properties.
Plastic polyethylene greenhouses
o While not as durable as glass or polycarbonate, they are available in smaller sizes, are lighter, easier to install, and are more affordable, and can last up to 20 years.
o For these reasons, plastic is the most popular choice for small commercial and home gardeners.
Wall-mounted or lean-to greenhouses are built against an existing structure and have the advantage of using an existing wall as a weight. They are lighter, often less expensive, and are wonderful for growing seedlings, herbs, and some vegetables.
How to use a greenhouse.
With fall approaching, I will move potted outdoor ferns into the greenhouse, and I plan to start seeds for some perennials to be transplanted in very early spring. I propagate plants for next season from cuttings of already lush geraniums and coleus, and in cooler weather I will plant lettuce and spinach. Even in an unheated greenhouse, you can successfully grow Bok choy, Chinese cabbage, kale, peas, and potatoes. In addition to being used for seed starting, plant-holding, propagation from bulbs and cuttings, and vegetable production, I also enjoy my greenhouse as a lush sitting room. With snow on the ground on a sunny day, it can be eighty degrees in there! Besides having the continued winter joy of puttering with plants, my greenhouse is a magical place to read, write, draw, have lunch and yes, sometimes nap. Perhaps it’s time to consider a greenhouse of your own.
Article by Mary Alice Ramsey, Buncombe County Extension Master GardenerSM Volunteer
For more information:
NC State Publication, AG-426: A Small Backyard Greenhouse for the Home Gardener: https://content.ces.ncsu.edu/a-small-backyard-greenhouse-for-the-home-gardener