Tomatoes self pollinate, but other plants like squash, zucchini, cucumbers, melons of all sorts need the bees to pollinate them for growth. Sometimes there aren’t any bees though and you need to pollinate the plants yourself. It’s easy and quick you just need to know what you are looking at.
I pollinate my squash and zucchini even when we have bee’s around. Mostly though, during the last weeks of May and into June it’s rainy and the flowers end up closing before the rain stops, which means there’s no squash coming our way. The bees miss the action so I do it myself. This is how I ended up with my ZucchiniZilla , maybe I can grow another mutant squash 🙂 (make sure you stay within the same species of squash if you are thinking of saving the seeds. If you cross pollinate outside the species you won’t get the same “parent” plant seeds)
What you need to know is where your females are and where the males are. There are two easy ways to tell. First is the stems.