Without proper care and maintenance, a greenhouse could turn into the opposite of what it was built for. Instead of protecting crops, it could be their death. At the very least, it could make your gardening efforts less productive and efficient.
For example, dirty windows can reduce the amount of sunlight that gets to the plants; gutters can become breeding grounds for diseases; and cracks and crevices can serve as hideouts for pests.
These create a perfect situation for pests and diseases to flourish. It is an unavoidable side-effect of gardening activities. Plus, it’s easy for such problems to develop in an enclosed space like a greenhouse.
That is why you need to know how to clean your greenhouse properly. You probably already engage in some greenhouse maintenance practices. However, those are never enough. So, read on to learn how to do a deep clean that will reset the state of your greenhouse and make it perfect for plants again.
How often and when should you clean a greenhouse?
Once a year is good enough. As for the issue of “when”, the off-season is the best time to clean. By this, we mean the months when little to no plants are growing in the greenhouse. Any other time would be stressful and hazardous for you and the plants.
Therefore, the best time to clean your greenhouse is outside the growing season. This could be anytime from when you harvested the final crops of the last growing season to before you plant the first crops of the next growing season.
For most people, this will fall between autumn and winter. However, you can clean your greenhouse anytime, even in summer or spring. Just find a period when the greenhouse is empty (free of growing plants) or as empty as possible.
It will save you the trouble of having to move plants around. However, should you have to do that, it is not the end of the world. You can just move those plants outdoors until you are done cleaning. It will only take a couple of days.
However, don’t try this in winter. The cold could kill those plants. Still, you can get away with this in autumn. The weather is not as severe.
Another option is to evacuate the plants to a temporary base. This new base can be anything, such as a room in your house, a garage or a newly-erected plant nursery. Note that you must make this base conducive to plant growth. For tips, we recommend our articles “How To Grow Vegetables Indoors” and “A Guide To Growing Vegetables Indoors With Lights”.
There is another option with which you don’t have to worry about the weather. However, it only applies to those who like to bring greenhouse crops outdoors during the summer. Since the greenhouse is empty, you can use this opportunity to clean it.
However, autumn and winter are the more viable options for most people. Plus, efforts to clean the greenhouse during this period technically become part of the preparations for the upcoming growing season.
If you had to choose between winter or autumn, choose the latter. During this autumn, it will be easier to care for evacuated crops and pests won’t get the chance to overwinter in your greenhouse.
What supplies do you need to clean a greenhouse?
Here are the supplies you need to clean a greenhouse. You don’t have to get them all. Just one of two from each category.
- Sweeping supplies: Broom, broomstick, rake and vacuum cleaner
- Water supplies: water, bucket, bowl and hose
- Scrubbing supplies: Sponge, squeegee, brush and towels
- Cleaning liquid: liquid dishwashing soap and glass cleaner
- Climbing supplies: ladder or scaffolding
- Disinfectant: Bleach, 70% alcohol, vinegar, and hydrogen peroxide
How to clean a greenhouse in 6 steps
The entire cleaning process can be divided into two stages, cleaning and disinfection.
- Cleaning: This involves the removal of unwanted elements from the greenhouse and your gardening equipment. These unwanted elements include plant debris, dirt, spillage, clutter, algae, moss, weeds, fertiliser residues, etc. Firstly, you will sweep and/or scrub off those elements. Then, you will wash with cleaning liquid and water.
- Disinfection: This involves applying disinfectants to kill pathogens and sterilising the greenhouse and its equipment. Without disinfection, your efforts are incomplete. So, don’t just wash alone. Disinfect everything, including containers, tools, and the floors and internal walls of the greenhouse.
Now that you understand the process, here is how to clean a greenhouse in 6 steps.
Step 1: Empty the greenhouse
Bring out everything. Evacuate every removable piece of equipment, including containers, tools, existing plants and even the irrigation system (more on this in step 4). Remember what we discussed about caring for the evacuated plants. Don’t leave them at the mercy of unfriendly weather.
The point of this step is to remove things that can get in the way and allow access to every part of the greenhouse. Those hidden spots can serve as hideouts for pests. So you want to be able to access, clean and disinfect them.
Step 2: Sweep the greenhouse
Now that the greenhouse is empty, the next step is to sweep. Do this to remove the unwanted elements that we discussed earlier. The floor is the main target but you should also pay attention to the drains, walls and roof. In simple terms, sweep every surface.
The point is to remove those unwanted elements that have accumulated inside and on the frame of the greenhouse. Doing this will make the next step easier and more effective.
Step 3: Apply cleaning solution
For this step, you will need a cleaning solution (liquid dishwashing soap, glass cleaner or any other garden cleaning product). You will also need water and scrubbing materials.
Your choice of supplies should depend on the material you are cleaning. For example, use a soft material like a squeegee or soft towel for glass or polycarbonate frames to reduce scratching. However, you will probably use warm soapy water and a sponge most of the time. You can also use vinegar and stain removal products to deal with tough stains.
Whatever the approach or choice of supplies, remember to wash and rinse both the interior and exterior parts of the greenhouse. You can use the ladder to reach the upper parts of the greenhouse.
Step 4: Clean the irrigation system
Technically, this is part of step 4. However, we decided to create a separate step because of how important this is. Over time, algae and bacteria buildup in water tanks can serve as ground zero for infestations.
So clean the water tanks. Empty the content and scrub the tank thoroughly. Don’t forget the pipes too. You can also remove the sprinkler heads for cleaning.
Step 5: Disinfect the greenhouse
Hope you remember our discussion on the importance of disinfection. The job is incomplete without it. So apply disinfectant. Whether you are using (bleach, alcohol or hydrogen peroxide, etc.), follow the instructions provided by the manufacturer.
You need to disinfect everything you have cleaned, including the entire greenhouse and irrigation system. Every piece of equipment also needs disinfection, but we will cover that in Step 6.
Step 6: Clean and disinfect the equipment
First, separate the equipment and supplies you don’t intend to return into the greenhouse. There is no point in cleaning those. Focus on the ones that are going back in. Clean everything, including containers, rakes, seed trays, trowels, hoes, shovels etc.
You can scrape the unwanted accumulates first, as you did with the greenhouse in Step 2. Then wash, using a strong brush and warm soapy water. After washing, rinse thoroughly and apply disinfectant. Do this for every piece of equipment.
Tips for cleaning a greenhouse
Before we say goodbye, here are some tips to make the task less stressful and more successful.
Give the greenhouse and equipment enough time to dry
Don’t rush back in. It could undo some of the progress that you have made. Give your greenhouse enough time to dry before moving the equipment back in. It could take a few days but the wait is worth it.
Protect electrical outlets before you start cleaning
You don’t want to damage those electrical outlets or injure yourself. So get a couple of waterproof protection for them.
Treat wooden frames with non-toxic vegetable horticultural oil
This protects wood from pests that may want to feed on or live in it. Those pests can damage your plants and the structural integrity of the greenhouse.
Many use non-toxic vegetable horticultural oil because it is efficient, easy to use and safe for plants, animals and humans. However, there are other options for treating wood.
Don’t forget repairs
Don’t just clean. The point is to put the greenhouse in the best possible shape. Therefore, it is also essential to take care of anything that needs replacement or repair.
Don’t forget existing problems
This is also the time to take care of lingering issues. Try to correct any particular growth requirement, pest, or equipment causing trouble.
Don’t bring unneeded items in
Don’t bring in items that you don’t need. They will only take up space and serve as a hideout for pests.
This is a good start. However, proper greenhouse maintenance is not limited to annual clean-up. You still need other measures to keep your greenhouse in good shape. These measures could be daily, weekly, bi-weekly or monthly etc.
Just do everything you can to keep your greenhouse clean. You can start with the following.
- Don’t bring infected plants, equipment, soil and other supplies into your greenhouse
- Clean the greenhouse glass regularly
- Clean every piece of equipment regularly and after use
- Don’t allow dirt, debris, diseases and pests to gain a foothold.