Garden & Greenhouse


Prepare the Greenhouse for Winter

It may be a little late for some of the country, but most of us still have nice enough days to prepare our greenhouse for winter. This is a crucial step to ensure that you have the best crop and most success with your greenhouse this winter.

This time of year my greenhouse is empty, so this is much simpler for me. If you currently have plants in your greenhouse, wait for a nice day and take them all outside and inspect them. Look for any bugs that may be hiding and dispose of them right away. Look for dead leaves and remove all of these. Just make sure that your plants are as healthy as they can be when they will be returning to the greenhouse.

Check and Seal Cracks & Crevices

Now that you have the greenhouse empty, check the actual structure. Are there any loose panels? Are there open cracks and crevices that need filled? Check around the doors and any open areas like roof vents, exhaust fans and intake shutters to make sure they have a good seal.

Check the Heater

Check your heater or better yet, get a professional to check your heater. Make sure there are no leaks, etc. and that everything is nice and clean and in a good operable condition. If you need to replace your heater or get it repaired, do not wait until the last minute. This is one of the most important systems to check for winter operation. If you have a small backup heater make sure you get it checked as well.

Clean the Greenhouse

Clean your greenhouse from top to bottom. It should be completely empty when you are doing this including removing all items like benches, etc. Clean the benches and other items before returning them to the greenhouse. I always have greenhouses glazed with polycarbonate, but if you have a glass greenhouse this is the time to clean the glass. Use a soft brush, like a car washing brush and a mild dish detergent to clean the surfaces inside and out. Rinse well and let everything dry before returning anything to the greenhouse.

Check and Repair the Polyfilm

If you have a polyfilm greenhouse, check for any new tears or small punctures. Be sure to use greenhouse polyfilm repair tape and repair these now. Or, if your inspection turns out with more damage than you thought, order a replacement cover and get it installed as soon as possible.  Also make sure that all of your clips or fastening system is good and tight. You don’t want your cover blowing off in a cold winter wind. If you are using a double layer with a blower make sure to check this if it has not been in use.

Final Inspection and Repairs

Now that the greenhouse is clean and ready for plants to return, complete any final preparation that is needed. In some colder climates an extra layer of layer of insulation can be placed around the vents, fans and intakes. It is also a good time to the covers from last year to make sure they are in good condition and replace them if needed. To prevent damaging any systems, be sure to shut off all of the exhaust systems before attaching any additional covers. Remove or disengage any automatic roof vent or side vent openers. This is also the time to install a winter heat blanket inside the roof that can be closed at night.

If you are using any types of hydroponic or aquaponic systems be sure to clean and check them as well. Any supplemental lighting should be inspected at this time as well. Water sources should be checked or turned off if they are not useable in the winter. Frost proof hydrants can be installed so water is readily available year round.

Remember, this is your last chance to check these before filling the greenhouse for winter. This is similar to spring cleaning in the home; just be sure to give everything a thorough inspection and you and your plants will be much happier in the coming winter months.

Tammy Wylie has been selling and installing greenhouses since 1993. She is the owner of Advance Greenhouses and blogs at where she discusses different growing methods including container, greenhouse and garden growing. She can be contacted at

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