Spring Greenhouse Cleaning comes Early - BC Greenhouse Builders

Spring Greenhouse Cleaning comes Early

Posted on November 16, 2020 | Categories: greenhouse bugs, Greenhouse Care, greenhouse pests, Greenhouse Tips















Spring Greenhouse Cleaning comes Early

My husband and I planned a mid-week ski trip but on departure day I was still in my office mid-day finishing a time-sensitive project. We were staying overnight at the hill, it was still a work day, and the car was loaded. There was no rush to get moving.

But my husband was off work for the day, his bags were packed and he kept checking in with me asking if I was ready to go. I finally a sked him to help us get ready by cleaning out the fridge.

I am not sure if he had any previous experience with this task or if it is just the way I worded the request but he got right on it. Except he didn’t clean out the fridge, he cleaned it: a much more intensive job that took hours.

“Cleaning out” – in my vernacular – means tossing the old food and pouring out the milk. “Cleaning”, means scrubbing down all the surfaces. It is a much more intensive task.

At this time of year, it is fine to “clean out” the greenhouse. But if you have time, cleaning is a good idea too. Get rid of dead or dying plants, weeds and other stuff that will rot, melt down or cause problems going forward. But if you have time, sweep the floor and wipe down dusty, spore-filled surfaces, empty pots and do a bit more than tidy up.

Keeping the greenhouse clean – or at least tidy – helps defer so many future problems. And that is why, in mid-November I am cleaning out and cleaning my greenhouse.

And in case you are wondering about timing, the best time to clean the greenhouse is when you have the fewest plants growing. This is why true spring cleaning doesn’t work for gardeners. Spring is that special time of year when we have shelves spilling with potted tomatoes, beds packed to capacity with winter crops, baskets hanging from the roof and extra pots of geraniums spilling out into the paths and beds. Spring is the opposite of empty. November is my season for cleaning.

Here are six tips for cleaning your greenhouse this month:

Pick a sunny, warm cleaning day-

After a big snowstorm in Calgary last month, early November brought highs of 23 C and in Toronto after heavy early season frost they had temperatures in the 20’s last week. In other words, you never know when you are going to get a sunny day so jump on it and dedicate time to your greenhouse. It will be good for your own positive vibes to get into the warm greenhouse sun and it will be good for the garden too.

Cut back on water and watering-

A sunny day makes you think of spring when you can almost see the plants grow as the sun shines brightly. But it’s going to get cool, cloudy and maybe even snowy again soon. Sitting water is never a good thing so I stop watering in fall because extra moisture and cold soil encourages insects like fungus gnats to multiply.

If the soil is moist in fall going into winter there is no need to water for a really long time. Days are so short and temperatures are cool so the plant demand for water is definitely down. I shut off the water and disconnect the hoses at this time of year to stop drips and accidental floods. Winter crops are in “holding” mode because they are not growing vigorously. Your greenhouse becomes a fridge for the cool season plants. A little hand-watering, if needed, can always come later. Today is shut-off day.

Remove cobwebs-

While spiders are largely good in gardens, they sometimes offer a runway to the creepy little critters that are distantly related – the spider mites. Luckily spider mites will go dormant this month, but their hideouts can be the cracks and crannies so they are worth cleaning. Using a duster from your house to remove the visible webbing and insects you see in your corners and ledges. Wipe surfaces with a damp cloth and a bucket of soapy water.















Remove extra plants-

Yes, there are still a few flowers and fruit on tomatoes but with diminishing light there are fewer and fewer fruits setting.  And if you are not heating your greenhouse, warm climate plants will quickly perish and start to mold and spread spores. It is time to turn the greenhouse over to cold season plants like mustard greens, watermelon radish, spinach, arugula and root crops like carrots and beets. Unless you are heating to summer temperatures, the warm season crops like melons, cucumbers, tomatoes and peppers are pulled now. Pick the fruit first and then pull the plants.

Wash overwintering plants-

I leave lemons and lime trees in my greenhouse over winter but I wash the leaves of these plants to remove pests or diseases first. It is common that cool nights and warm days encourage sooty mold growing in the honeydew of scale insects. First I remove the scale adults with a q-tip dipped in alcohol then I wash leaves with a soapy soft cloth. Right after I clean them, I cover the plants with protective Ag-30 agribon cloth  to give them extra protection over winter.

Wash fabric row covers-

Plants still growing in your garden are going to be kept overwinter are often covered with row cloths. If these are washed before they are put away there is no need to wash them now. If you accidentally put them away dirty give them a quick run through the machine before laying them over or wrapping up your winter plants. The clean cloth means there is no accidental introduction of mites or aphids into the greenhouse from its last use outdoors.

A commercial grower once told me to keep my dog out of the greenhouse. “Dogs can pick up spider mites on one side of the greenhouse and drop them off in another,” he told me. And you will not see it happening. So as you do your “spring” cleaning this fall, keep the dog outside.

It is sunny today so I will start the cleaning today because the darkest days of winter are coming and I have time now.

But maybe you are wondering if you ever really need to clean your greenhouse? Insects hide in cracks and crannies and are moved around by pets and gardeners and ants. Mold grows on wet soil, fungus gnats thrive in damp moss, and weeds produce seeds ready to spring out into the planting beds. So yes, it is a good idea to dedicate a day to spring cleaning at your first opportunity.


And in case you are wondering, when we arrived at our hotel near the ski hill we were in time for dinner and drinks with friends and we told long tales of the clean out vrs the clean fridge.  Our friends laughed and of course invited Keith to come clean their fridge any time he was available. It was an impressive and sparkling job done to perfection.

Whether or not your greenhouse is cleaned to perfection this fall is up to you. I suggest at least cleaning out if not cleaning up. It really makes a difference.

For more great tips from Donna, visit www.donnabalzer.com.

You can also read Donna’s gardening books: No Guff Vegetable Gardening with Steven Biggs and her just released Gardener’s Gratitude Journal:  Part Diary, Part Personal Growing Guide.

donna balzer