Greenhouses allow us to tend to our plants all year round and can be a source of great joy, and productivity, for many gardeners. But the greenhouses themselves also require some care, and potentially most important of all, is keeping the glass clean.
The power of greenhouses lies in how much sunlight they let in, so grime-covered windows will impair the environment they create for seedlings and plants to thrive. Knowing how and when to clean your greenhouse glass, as well as what to use and what to avoid, can make this task much more manageable for greenhouse gardeners.
This guide aims to offer the best advice on cleaning your greenhouse glass for brilliant results, as well as highlighting the most suitable products and eco-conscious choices.
When should you clean your greenhouse glass?
Your greenhouse glass cleaning schedule works best with the seasons. Ideally, you should do a complete glass clean biannually – once during the spring, to remove the dirt of winter, and once in the autumn, when the sunlight becomes less abundant.
Spring cleaning: As the days lengthen and the temperature begins to rise, the onset of spring presents the ideal time for preparing your greenhouse for the impending growing season. Early spring cleaning, with the aim of removing winter grime and dirt, will help sunlight to penetrate, and increase the light to your newly planted seedlings and early crops. This is also the perfect time to clean, because you will reduce the potential for pests and diseases to linger in the greenhouse and cause issues as the summer arrives.
Autumn cleaning: At the tail end of summer, an autumnal clean is just as important for your greenhouse. As the height of the growing season draws to a close, cleaning the glass prevents the accumulation of dirt and algae during the colder months, and maximises light as the sun starts its descent into winter. If you have used shading paint to prevent the greenhouse getting too hot over the summer, this is also the time to remove it. This preparation ensures your greenhouse stands ready for the forthcoming winter growing season without requiring extensive cleaning. Cleaning before the cold arrives also makes it easier to move plants temporarily that might otherwise suffer in lower temperatures.
Of course, if something causes your greenhouse glass to get dirty between these biannual cleans (ahem, birds!) we recommend cleaning smaller patches as you go along, especially in the months where you want to maximise the light entering your greenhouse.
Preparing to clean your greenhouse
Make sure you know what type of glazing your greenhouse has, and check the manufacturer’s notes about safety when cleaning.
The last thing you want is to break a pane as you clean, or use a product that could cause damage, so take a moment to make sure you have a safe plan for reaching the highest panes, both inside and out. Our Premium Rhino range of greenhouses have an ultra-strong frame and unique glazing system – if your greenhouse is a different make, it’s worth checking your manufacturer’s guide about safety when cleaning.
Unless you’re marrying your glass cleaning with a full deep clean of your greenhouse, you don’t need to move all plants outside. But you do need to make sure to move any plants that will get in the way of reaching the glass, or that could be harmed if you have to push past them. Before starting your glass clean, make a plan of which plants need moving, and where you will put them.
Outside your greenhouse, you need room to reach the glass on all sides, and on the roof as well. If plants need to be cut back to give you access, these times of year lend themselves to clearing and pruning.
If you need to stand on something to reach the root panes from the outside, make sure it is safe and sturdy. A movable a-frame ladder is a good option, giving you something to hold on to as you clean, without leaning on the greenhouse itself. Remember to move it regularly, rather than stretching and reaching.
The best products for cleaning greenhouse glass
- Warm soapy water: Simple is definitely best here. The most environmentally friendly and economical solution to clean your greenhouse glass is warm soapy water, prepared by mixing a few drops of mild dish soap into a bucket of warm water. Use a soft sponge or cloth to rub the glass. This method is both plant and environmentally friendly.
- White vinegar: In cases where hard water stains or mineral deposits smear the glass, a mixture of white vinegar and water (in equal proportions) is an effective natural remedy. Apply this solution with a sponge and ensure thorough rinsing to ensure no odour is left behind.
- Squeegee: As well as these cleaning products we recommend a good quality squeegee for removing excess water, leaving your greenhouse glass free of streaks after applying soapy water or rinsing off your vinegar solution.
A note on commercial Glass cleaning products: Commercial glass cleaners can be an option, but we always advise caution when it comes to introducing chemicals to your greenhouse environment. If you do have to use them, do so sparingly, and seek out environmentally friendly, ammonia-free variants and adhere to the manufacturer's guidelines. Thorough rinsing post-application is imperative, and make sure no run-off water seeps into any soil.
In most cases, warm soapy water, followed by a white vinegar solution when needed, will be enough to clean your glass perfectly.
What to avoid using when cleaning your greenhouse glass
While cleaning your greenhouse glass, it is important to avoid products or practices that could jeopardise your plants, the environment and your greenhouse.
Harsh chemicals: Avoid using bleach, ammonia-based cleaners, or any substances likely to leave plant-harming residues or pose an environmental hazard.
Abrasive tools: Avoid the use of abrasive tools, as they may damage the surfaces of your greenhouse. Abrasions can lead to the accumulation of dirt and algae over time. We recommend sticking to soft sponges and cloths.
Pressure washers: High-pressure water has the potential to damage the seals of your greenhouse and force water into undesired areas. Gentle hand-cleaning methods are the better option.
Excessive cleaning: While cleanliness is essential, cleaning too much and can disrupt the delicate balance of your greenhouse’s ecosystem. Avoid disturbance to your plants, focusing primarily on glass cleaning.
Complete List of what you need to clean your greenhouse:
- Clean water, from your garden hose or in a bucket
- Warm soapy water (warm water & mild dish soap)
- Vinegar solution (50/50 water and white vinegar)
- A cloth or non-abrasive sponge
- A squeegee
- An A-frame ladder or other safe platform to stand on (if needed)
Step-by-step: how to clean your greenhouse glass
- Clear the space inside: Relocate all plants, equipment or tools that may obstruct the process. Doing this before you start helps you be as efficient as possible once you get cleaning, and also helps protect your plants from cleaning solutions
- Make space outside: Ensure you can reach all sides of the glass outside, and cut back plants where needed.
- Pre-rinse with water: Start the clean itself by rinsing the glass with clean water, to eliminate loose dirt and debris. A garden hose or a bucket of water will suffice.
- Start cleaning: Dip a soft sponge or cloth into your warm soapy water and gently rub the glass. We recommend working top to bottom, first outside then inside.
- Address tougher spots: If you need more cleaning power than soapy water provides, use a vinegar and water solution. To prevent unsightly drips and streaks, work your way down from the top.
- Rinse again: After cleaning ensure the glass is thoroughly rinsed with clean water from your hose or from a bucket.
- Dry with a squeegee: Start from the top and work down in horizontal swipes from left to right.
- Air out your greenhouse: If you have time, leave all ventilation open and let your greenhouse dry.
- Put your plants back: Once the glass is spotless and dry return your plants to the greenhouse.
Clean greenhouse glass is a cornerstone for fostering optimal plant growth and creating an inviting gardening environment. By cleaning your glass twice a year, using simple products and gentle cleaning techniques, you can ensure the longevity of your greenhouse while preserving the well-being of your cherished plants.
So, set aside some time this spring or autumn to give your greenhouse the TLC it deserves, and watch your gardening efforts flourish in the beautiful, sunlit haven of your greenhouse.