When should I start and stop monitoring my site?

It's best to monitor every week as soon as the milkweed comes up. It is just as important to document monarch absence as it is to document presence. You will almost always see eggs before you see adults, so you shouldn't wait until you see your first adult to start monitoring. In the fall, you should monitor until all of the monarchs are gone. We recommend going out twice after you've seen your last egg or larva.