I have long complained about my greenhouse, although I am often quite grateful for owning it.
I bought it from a hardware store several years ago and it while it has proven useful, I have had many problems with it. Firstly, it is not the strongest or most resilient of structures… several times I have lost seedlings to high winds. The shelves in the greenhouse have actually moved in the wind and thrown the seed trays to the ground. I have also had problems with Possums ripping open a hole in the roof, making a mess in the greenhouse by knocking seedlings and buckets to the ground. Finally, I have had a problem with birds and mice. They have destroyed seedlings, eaten large amounts of fodder, and crapped all over the work surfaces.
In summary, I am continually improving the greenhouse and I often have to come up with solutions to meet my challenges.
The latest challenge I am attempting to overcome is the problem with rodents and birds attacking my seedlings. They have, in the past, destroyed many tomato plants by chewing on the stalk and undoing months of hard work. In order to stop this from happening I have attempted to wire the greenhouse base to stop their entry (no luck there), placed mouse traps to catch the rodents (I have caught many, but I have better luck with them falling into a bucket of soaking fodder and drowning), and moving them to high shelves (they just climb up and eat). I have decided that I will make a tiny fortress for my growing plants, so to that end I have built the fortress of isolation. It have used an old piece of wire flooring from the Rabbit hutch I used to have, bending it into a shape to protect three of the 6 sides. I then placed some excess wire on two of the sides to prevent access before placing it on to a plastic tray (which was part of my old finch bird house).
So far it seems to be a good shield from little animals, while still allowing light, air and water to reach the plants. It will limit my growing, yet it is only part one of my plan as I may consider building more or modifying a structure to protect more than one tray.