What is the best type of Greenhouse for my use? Will I need to heat my greenhouse in the winter to keep my plants alive?

I am often asked what Greenhouse is best for wintering plants? And my question back has always been two fold; “Where do you live and what type plants are you wintering over?”

Your location and type of Greenhouse you have or plan to get can make a big difference in whether or not you can do what you intend.

A simple plastic covered greenhouse that is being used in a cold climate area where the night time temperature drops to 40 degrees or less is only good to store dormant perennials that are potted so that any freezing wind won’t damage you plants roots and will help warm up the pots in early spring for faster growth and budding. You can add some form of heat to speed up the warmth but it has been my experience that this can be costly.

If you want to propagate perennials all winter and store older plants then a polycarbonate greenhouse would hold in heat better and your success will be much higher the more thickness of polycarbonate wall you have. These are measured in single millimeters, 2mm, 4mm, 6mm, 8 and 10mm is best suited for the colder climates.

4mm and up approx R factors:

4mm twin wall polycarbonate = R 1.43

6mm twin wall polycarbonate = R 1.54

8mm twin wall polycarbonate= R 1.61

10mm twin wall polycarbonate= R 1.89

Type of heat used can be, (my favorites,) propane or natural gas, or you can use electric heat, (doesn’t heat well with out good blowers to distribute which brings up the cost to run in any greenhouse.) but no matter what type of heat you choose do include good circulation fans so that the heat is distributed evenly through out the area of your greenhouse, this can reduce heating cost by 5% and prevents mildew and damping off on plants. Ventilation is still important in any greenhouse so keep that in mind, yes even in the winter.

Approx. Temperature need for plants:

Cold temperature of lows in the 40’s and below in a greenhouse will help keep off hard freeze of dormant plants.

Cool temperature of 45 to 50 degrees is good for leafy and root crops that like cooler weather.

Moderate temperature of 55 to 65 degrees are good for propagation, cucumbers, beans, herbs, Ivy and flowers.

Warm temperature of 65 to 70 degrees to do well. Tomatoes, Peppers, Tropical plants, (and pretty much anything else you wish to grow,) plants also need added growing light if started in winter when sunlight is low and short term, and good heat pads to propagate well. In fact in the winter any plants you are trying to grow or start will need the added growing lights and bottom heat to make for healthy roots and strong stalks that are not leggy. Water and fertilizing is equally important.

In the heat of the long summer days you will need to consider the cooling and ventilation needed to keep your greenhouse plants healthy. Shade cloth is a good thing to have available for hot days as well.

For those who live in moderate to warm climate the single pane polycarbonate house do a good job in keeping your plants.

None of it is hard to learn and having a greenhouse can sure make the long winter days seem shorter and your spirits high.

It doesn’t matter if you grow in a greenhouse or in a pot on your window sill, gardening of any kind is great for the soul. My Momma use to say,” No matter where you live plant something that will grow it is your tithing to the world.”

Theresa Saldivia, I have over 30 years of commercial and hobby greenhouse growing and have been an organic grower all my adult life. I have the great pleasure of being the Sales Manager for 4seasongreenhouse.com.

Need help? - Our experts are here to help you pick out everything you need for what your growing and the climate you are in to get the most out of your new greenhouse. Call us 1 866 567-0813. We are real growers with hands on experience and enjoy sharing our love of gardening.