I got myself a net
I have decided to put a big green garden net over all of my wheatgrass from now on to protect it from all the crazy pests that are lurking nearby. I just propped it up with stiff wire, and tuck it under the trays, and I have an easy protector of my grassy green stuff. Last year I had lettuce that was just about ready to pick growing on my balcony when I discovered little green eggs all over it. The next day the eggs hatched and within 6 hours or so nearly all of my lettuce had been devoured by caterpillars--Zoinks! Although I have had no such problem with wheatgrass so far, I don't want to take any chances. In any case, it keeps the pigeons at bay a little.