Updated at: 27-04-2022 - By: Sienna Lewis

Inexperienced greenhouse gardeners are understandably curious about cleaning their greenhouses. In the dead of winter, no one wants to go outside and shovel snow. Although cleaning out your greenhouse may not be your idea of a fun weekend project, it is necessary if you want to improve the growing conditions for the plants in there.

Your greenhouse can become covered with moss and algae in as little as one year before the quantity of light it lets in is reduced. Getting rid of pests that are overwintering in your greenhouse and preventing diseases that could put all of your gardening efforts to waste are two more essential reasons to clean your greenhouse.

To get a sense of how to clean your greenhouse, have a look at the most often asked questions from gardeners.

About Sanitizing a Greenhouse

It doesn’t matter if you’re a home gardener or a business grower; maintaining a clean greenhouse is critical. The growth of potentially infectious microorganisms can occur during the course of a growing season in addition to the growth of plants. Fungus gnats and coast flies thrive in damp environments, which algae thrive in as well. As the saying goes, the best treatment is prevention, and this is certainly true. Insects and diseases can be nipped in the bud if the greenhouse is kept clean. It is imperative that the greenhouse be cleaned and sanitized as soon as possible to prevent pests from overwintering.

Greenhouse Cleaning - How to clean your Greenhouse

How to Clean a Greenhouse

Once the greenhouse has been thoroughly cleaned and cleared of unwanted materials, it is time to sanitize it once more. Weeds and other living plant material must be removed from the greenhouse during the cleaning process. Also, get rid of any plant waste, soil that has spilled, and any other clutter in the greenhouse. Use a shop vacuum to pick up loose dirt, shattered pottery shards, etc. after you’ve shifted these objects. Power wash or scrub algae, scum, and fertilizer residues from the surface of the water. Use a soft, natural soap that doesn’t leave behind any residue.

Power wash or scrub algae, scum, and fertilizer residues from the surface of the water. Use a soft, natural soap that doesn’t leave behind any residue.

Weed barrier may be installed in an effort by growers in the future so that cleaning algae and spills may be done more quickly and easily.

How Do I Sanitize a Greenhouse?

In order to sanitize a greenhouse, there are four techniques of disinfection.

  • Alcohol– Although 70% alcohol kills germs on contact, the consequences are short-lived because alcohol is volatile. Equipment like as shears and propagation knives should be sterilized with alcohol.
  • A typical disinfectant is bleach, which is also the least expensive. It’s a fact of life that bleach’s effectiveness degrades after two hours of dilution. As a disinfectant, bleach is mixed with water and applied to the surface to be cleaned. Rather than using it as-is, a bleach solution is prepared by diluting it one part bleach with nine parts water. Remove any soil or organic matter from plants or flats before disinfecting with bleach.
  • In addition to chlorine dioxide, hydrogen dioxide can be found in brands including ZeroTol, OxiDate, and SaniDate. It can be used to clean benches, pots, tools, and other surfaces. It will eventually lose its effectiveness, just like bleach. A simple test can be done to verify if the remedy still has the desired effect. If this isn’t the case, more hydrogen dioxide will have to be incorporated.
  • Because of this, quaternary ammonium chloride salt is more effective than hydrogen dioxide or bleach, which can lose their potency over time. Pots, flats, and other containers can be used, but they must be cleaned of any organic material first.

When is the Best Time to Clean a Greenhouse?

When your crops have been harvested, now is the greatest time to get some housework done. This allows you to remove your overwintering plants without having to worry about the greenhouse becoming full. A warm bright day between November and February is ideal for cleaning your enclosed botanical space, although the exact dates will depend on when you want to clean.

Depending on the plants you’re cultivating, you can also decide how often you want to clean your greenhouse. If you have summer cropping tomatoes, you may want to do this in the winter. Cleansing during the mild fall months is a good idea if you’re cultivating year-round orchids, since this will allow for maximum sunlight penetration before the winter season arrives.

You should clear out your greenhouse in the fall or spring if you’re producing vegetables or seedlings on a regular basis.

What are the Steps Involved in Cleaning the Greenhouse, Gutters, and Water Butts?

Pick a day when the weather is quiet and dry to get the cleaning done.


The first step is to get rid of the plants. Plants should be placed in a fleece-protected area while you’re doing the cleaning.

Because you cleaned the structural parts with disinfectant or detergent solutions, you should use a brush or a vacuum to remove the dirt and debris. Using hot solutions is preferable, however, the sort of material in your greenhouse may preclude this. You can also use hydrogen peroxide-based cleaning solutions and other household cleaners.

You should consult your greenhouse maker for cleaning guidelines to ensure that you’re doing it correctly. To clean glazing material, you must wash it both inside and out. Testing the cleaning agent first in a small inconspicuous location is necessary if you’re working with plastic greenhouse material to ensure that it won’t damage the glazing.

Draught excluders and vent controls, for example, should be replaced if they’re broken. Don’t forget to keep an eye on your equipment and the propagation points.


Detritus can readily clog the gutters. Gutter maintenance is critical to ensuring that water can freely flow through the system.

You can start by donning rubber gloves and running your hand along with the gutter’s interior. Make use of this technique to remove dead organic stuff that has accumulated over time, such as moss and leaves. Unclogging the fall pipes’ tops may necessitate the use of a wire coat hanger.

Put a wire mesh cap over the fall pipe after you’ve cleaned out the gutters with a watering bucket or hosepipe. Larger debris can be caught using this technique.

Maintaining this area is essential, so don’t forget to do it often. Place the organic waste on the compost pile to help it decompose.

Water Butts

As it turns out, some of the algae that accumulate in stagnant water are capable of causing water-borne root rots. It is recommended that water butts be cleaned out at least once a year to maintain their effectiveness.

To begin, drain the water by pressing the button on the side of the device. Cleaning it will become easier as the dregs are removed.

Use a coarse brush and a cleaning agent to clean out the inside of the water butt, if possible. For regions where you can’t reach, tie the brush around a stick. Use clean water to rinse when you’ve finished scrubbing.

To prevent algae growth, you’ll need to refill the container before adding the water butt freshener. When rainwater enters the water butt, it will dilute the strength of the water. Make careful to carry out the therapy procedure as required.

How to clean your greenhouse - YouTube

Experts recommend using tap water for your seedlings and tender seedlings, even if the water is discolored and stinky. In order to ensure that rainwater collected in the water butts is pure, you need to attach the filters to rainwater diverters. Old tights can be used as a filter if you don’t have access to more complex tools.

Finally, install tight-fitting lids to prevent soil and plant debris out of the water butts.

Moss and algae create issues in the greenhouse

In terms of reducing light transmission, moss and algae play a major role. Both compete with plants for nutrients and can attract fungus gnats, but neither is harmful to plants directly.

Reducing pests and disease

Gardening in greenhouses is made easier by their semi-closed, sheltered conditions. Plant fungi and diseases can thrive in these areas since they’re a great place to hide out. What to check for and how to avoid greenhouse diseases have been compiled by the University of Vermont. Maintaining cleanliness and sanitary conditions in the greenhouse is an important part of controlling all of these issues.

  • A white powdery deposit on the leaves of plants can be a sign of powdery mildew. Plants that have been infected with the fungus, both living and dead, are infested with it.
  • Leaves are killed by Botrytis, a fungal infection that produces a brown or grey slime on them. As before, it thrives in hot and humid conditions, and it wreaks havoc on plants that have been harmed or are just beginning to grow. ‘Damping off’ is caused by Botrytis.
  • There are rusts, which look like rusty specks on the foliage. Plants can be killed or severely stunted by severe attacks.

Slugs, snails, and insects

Slugs and snails, as well as fungus gnats and plant infections lurking in plant detritus and filth, pose a more recognizable threat. In the beginning, you think you’re safe in your greenhouse until you take everything out and thoroughly clean it. While cleaning my greenhouse this week, I discovered a large number of slugs and their eggs.

Additionally, a deep clean can remove pests such as red spider mites, whiteflies, and caterpillars, as well as mealybugs. Among the reasons for this is that many of them survive the winter in their eggs. You may get rid of them by washing the greenhouse, replacing the compost, and sanitizing the pots and trays by spraying them down.

When we clean the greenhouse, we give it a new lease on life and reduce the danger to our plants. The University of Kentucky provides a list of pests widespread in the United States and how to deal with them if you’re fighting another type of bug in your greenhouse.

How to Deep Clean the Greenhouse

Cleansing to the core After removing all or most, if not all, of its contents, a greenhouse begins. Afterward, a thorough cleaning is required. Remove as much of the dry material as possible before adding the wet material. As for the outside, it should be cleaned from top to bottom with the goal of removing any debris that may be obscuring the glass or making its way into the wood or metal frame. Cleansing is the next step, and there are numerous options on how to accomplish this. Your fresh spring plants will thrive in a sparkling clean greenhouse.

Check-list for cleaning the inside of the greenhouse

Step-by-step instructions for cleaning my greenhouse. Both my current glass greenhouse and the plastic poly-carbonate greenhouse that I’ve had for the past few years have been equipped with them.

  • Remove all of the greenhouse’s contents, including its plants and containers. Clean and inspect all of them for slugs, eggs, and insects that may have overwintered there, as well as to fully inspect and clean all of them.
  • Go from top to bottom, sweeping and mopping. Compost piles should not be used to dispose of plant material in greenhouses that have been plagued by illness in the past.
  • Remove large chunks of algae, moss, and other growth from all surfaces. If required, re-sweep the area to eliminate the remaining debris.
  • Begin at the top of the greenhouse and work your way down, filling a bucket with warm soapy water and scrubbing all the surfaces. An old toothbrush works well for little crevices, while a scrub brush is better for larger ones.
  • Remove any old paint by scrubbing it off.
  • Clean water should be used to wash away dirt and debris.
  • Allow for adequate drying time after cleaning and rinsing the floor.
  • To further disinfect and brighten the glass, you can apply a DIY vinegar spray once it’s dried.

Using Algon to stop algae growth

To further protect my greenhouse glass from the elements, I used non-toxic Algon on both the inside and the outside this year. Neither pets nor wildlife will be harmed by it, and aquatic life will be unaffected as well. The best part is that it can keep algae at bay for months at a time. However, metal should be avoided when using this product. I used a moist rag to wipe out all of the metal parts of the greenhouse in my cleaning video at the end of this piece.

Removing algae from between panes of greenhouse glass

I had a difficult time removing the algae that had accumulated between the glass panes during my most recent greenhouse clean. Traditional greenhouses had glass panes that overlapped one another, creating a solid green space in the middle of the greenhouse.

One possibility is that you could remove each pane and clean it individually if you had a week to thoroughly clean the greenhouse My time is limited, so I used a plastic plant label as the next best thing. You only have to wiggle it between the algae and push it out. It’s a great system. The rest of it is flushed out by a hose blast.

Check-list for cleaning the outside of the greenhouse

The drains and water butts must also be cleaned as part of the external greenhouse cleaning. Algae can thrive in both of these sites, and reusing water from your greenhouse can reintroduce them.

  • Remove all leaves, moss, and other debris from the roof, gutters, sides, and surrounding area of the greenhouse. ‘
  • Remove as much moss and heavier debris as possible from the glass. To get the job done, you’ll need a long-handled brush, scraper, and/or ladder.
  • Clean the top of the greenhouse with soapy water, then work your way down and clean out the gutters.
  • Use the toothbrush if necessary to clean the greenhouse outside.
  • Allow everything to dry completely after rinsing it off.
  • Make sure the water butts are dry before you wash them. Clean out the downspout if you have one to connect your gutters to the water butts. When everything else fails, you can just use an old rag wrapped around the handle of your vacuum cleaner.

This year, I also applied Algon to the exterior of my greenhouse. There must be no rain expected and the glass must be perfectly dry.

Deep Cleaning the Greenhouse with eco-friendly products

If a product has antibacterial properties or is created with substances that threaten plant and animal life, I avoid using it. It’s equally as beneficial to use an eco-friendly liquid soap like Ecover or a comparable brand.

In the home, anti-bacterial soap is a bad idea. Why? Because it eliminates 99.9% of the germs in the environment. The remaining 0.01% will be able to resist and reproduce, giving rise to superbugs. Using regular soap removes germs without amplifying the arms race between them and evolution.

Conventional greenhouse cleaners

For years, greenhouses have been cleaned using one of four different types of cleaners. A good wash with soapy water can be just as effective in killing bacteria and organisms as these chemicals. Except in the case of a serious illness, fungal, or mold infestation, these products should not be used to clean your greenhouse. They may, however, be useful as tools, workbenches or propagation spaces.

  • Bleach. Its production is not eco-friendly, even if there is little proof that it has a direct impact on the environment. Stains and smells are also a problem with it.
  • When inhaled or absorbed through the skin, the solvent alcohol (70 percent Isopropyl) can cause irritation. Sanitize tools with it, but don’t go overboard with the disinfectant in your greenhouse.
  • Carbon dioxide, also known as Hydrogen peroxide Several well-known brands of greenhouse and garden tool items contain this chemical, which is effective in treating wounds. Even if it’s used for tools, cleaning the greenhouse won’t require it.
  • Ammonium chloride salt with a quaternary group. A few well-known lawn cleansers include this compound, however it isn’t a good idea to use it. Aquatic life can be affected by QACs that remain in the environment for a long time. They can also cause skin irritation by remaining on cleaned surfaces and in waste water.

Steam cleaning

Steam cleaning, how I love thee. As if they were members of the family, some people talk about their steam cleaners. You can utilize the steam cleaning revolution in your greenhouse as well if you’ve converted to it. Ensure that the surface is clean and free of any large pieces of debris before beginning.

Greenhouse Maintenance | The Naked Truth continues...

Pressure washers

There is nothing better than cleaning the patio with a power washer. Seeing the original color of the paving stones is enough to keep me going for hours at a time when I’m pressure washing. Yes, freak on the loose.

Pressure washing my greenhouse is not something I would do. It’s very uncommon, but I believe the risk of glass breaking is just too large. We’d love to hear from you if you use a pressure washer to clean your greenhouse.

Please check out How to employ the Marie Kondo Method in the Garden if you found this article helpful and are seeking for more methods to organize your garden.

Keeping a Greenhouse Clean

You have a lot of work ahead of you, so once the greenhouse has been disinfected, turn over a new leaf and commit to take some steps to reduce future cleanup. Sanitize all tools, containers, and equipment immediately after use to prevent the spread of germs. Before handling plants, equipment, or soils, wash your hands with soap and water. Clean your gardening gloves. It is important to have a pair of solely greenhouse-only footwear. Don’t wear clothing that attracts insects such as yellow or blue, as they may follow you inside the greenhouse as you enter. Keep weeds in pots and off the ground at all times. Remove any infected plants as soon as possible. For safety reasons, don’t drape the end of your hoses over your shoulders.

A Summary on How to Clean a Greenhouse

Your work in the greenhouse can finally begin now that you are familiar with how to clean one. In the meantime, be careful to inspect the gutters and the water butts. Have a good time doing the housework!