If it is installed correctly, it should in no way harm your plants. We know that you have to spend a lot of time growing those plants from seed, and you don’t want to add anything that might inhibit their proper growth. There are some tight mesh fabrics on the market that are also designed to keep out bugs that might negatively harm your plants by not allowing them to get enough sun or water. You always want to make sure that your plants are getting enough sunlight and water, and you want to make sure they have room to grow. If you consider the alternative of keeping away pests- such harmful sprays that are filled with chemicals, the construction of a mesh barrier is the safest way to keep your fruits and vegetables to yourself. You just have to make sure that it is installed correctly and that your plants do not have to bend beneath it.