A greenhouse over winter will have accumulated bugs, spiders, leaves, other debris and perhaps some diseases. When you do a proper greenhouse cleanup prior to the growing season, you will have fewer problems later.
Most greenhouses are closed up for the winter. You maybe have some plants overwintering like I do, but nothing is likely actively growing if you have cold winters.
Humidity is usually higher in winter where it rains a lot (like on the we(s)t coast of Canada where I live) or when you get snow melt in early spring. This causes mildew, fungus and rot which needs to be cleaned up.
Diseases such as mildew and damping-off can also fester in a closed up greenhouse. Other debris may have accumulated on those rare times when the greenhouse is open and it is windy outside.
In general your greenhouse is likely not a very hospitable environment right now for young seedlings and plants, which are more susceptible to disease. So here are some tips on how to cleanup your greenhouse the right way and get a good jump on the growing season before it arrives.
Before you begin:
You will need to pick a sunny, warm day as you will be moving plants and other items out of your greenhouse temporarily. It doesn’t have to be summer-like. It can be an overcast day, so long it is slightly above freezing. A bit of wind helps as it will help dry things out.
If you live in a cold climate you may have to move plants to a sheltered location, but more on that later.
Start early enough in the day so you can finish on time as you likely won’t want to leave things outside overnight, especially plants. You may need half a day at least depending on the size of your greenhouse, how many plants you have overwintering and whether or not you will have help.
Speaking of help, you likely will have planters, bags of soil or other amendments and other items that are heavy. So you will need some help in moving things out of the greenhouse and then moving things back in at the end. It doesn’t hurt if your helper can also help with the cleaning steps.
1. Clearing out
First task is to clear out the greenhouse of as much as you can. Plants in pots, bags of soil and amendments, furniture, etc. Place all the items outside away from the door so you can still move in and out of the greenhouse easily.
For plants, you may want to consider storing them in a garage, garden shed or even your kitchen or basement if the weather outside is too cool. You don’t want to shock your plants by moving them from a much warmer area to a much colder area and vice versa.
2. Vacuum & brushing
Before you get anything wet, take the time with a wet/dry vacuum (not the one you use in the house on your expensive carpets and floors!) to vacuum up as much loose dirt, leaves and spiderwebs as you can.
You may need to brush first with a dry brush or broom to loosen up stubborn dirt and then vacuum it up.
3. Wash & Rinse
Now to wash everything down. If you haven’t done so already, protect anything that shouldn’t get wet with plastic bags or a tarp.
Get a bucket of hot water and add in cup of bleach (an oxygenated one, not chlorine). Using a scrub brush and starting at the top, brush down all surfaces as best as you can. Use ladders and long poles if needed but be careful.
Once you have brushed down all surfaces, take a hose and rinse everything off. You may need to go back with the brush to deal with any stubborn spots.
You should also pay attention to the outside of the greenhouse. Your main focus should be on the roof and windows to get them clean to allow maximum light penetration. Just don’t get anything wet that you moved out of the greenhouse!
4. Optional: Paint or Stain
If you notice paint peeling or wood surfaces needing a re-staining, do that now. If you don’t have the time (keeping in mind that you need to move everything back by the end of the day) you may instead defer it to warmer weather when paint and stain dry quicker.
5. Move everything back in
If you can, wait until the greenhouse has had a chance to dry out a bit.
Now for the fun part, moving everything back in. First, ensure that what you are moving in is clean. Again get out the vacuum and clean loose dirt and leaves. You should also wash down plant containers and pots to avoid bringing disease back into the greenhouse.
This is the time to reorganize your things, putting everything away neatly. Be sure to toss out anything you don’t need or haven’t used in a long time.
Now you can be assured that your greenhouse is clean, free of diseases and ready for another growing season.
Share in the comments how your greenhouse is looking right now. And remember to schedule some time in your calendar to clean it at the right time of year before you forget.