To achieve the full benefit of greenhouses, owners will have to keep them clean and well-maintained. An annual inspection and a few modifications should be enough; leaving it longer could entail more hours of work and cleanup, which costs more and shaves off time that could've been spent on actual gardening.
It's also important to ensure that it is kept clean throughout the year as well. Plants need all the sunlight they can get especially during rainy or snowy weather; so regularly cleaning the interior and exterior of your greenhouse is necessary to prevent dirt and certain debris from limiting the amount of sunlight allowed into the greenhouse.
You may be surprised to find out that a significant amount of time is needed to clean each panel in the structure. Beginners may find it easier to maintain theirs, as they tend to own smaller models, but more experienced individuals may find cleaning more difficult as their love for gardening will have led to the collection of more plant species and the necessary expansion of their greenhouse.
During summer, proper care and maintenance of greenhouses is essential in keeping insects and pests away from plants. Obviously, it's always better to clean the space when it's less filled, so schedule major cleanups before or after growing season—around May to October in the country's northern regions, and March to November for those in the southern-southwestern-Californian regions. In between seasons or when things are hectic in your greenhouse, even just hosing down the roof helps.
Try to choose a day when there is a gentle breeze to help the structure dry a bit faster, and lift off moss or algae that have taken root on the panels. For scraping these off, any tool that won't scratch and damage the panels is good.
If you're using anything but water to clean the greenhouse's panels, make sure to protect your plants from getting doused with soap or chemicals. You can move them outside if it's warm enough and you can do it without damaging the leaves. See to it that you cover sockets, heater and AC units, exhaust fans, and other electrical components as well.