Some vegetables are easier to cross then others. Vegetables with very small or multiple flowers in the same cluster are the hardest to cross. But many vegetables have relatively large flowers and are easy to work with. Squash is one of the best examples, with large yellow male and female flowers that are easy to cross. Saving seeds Saving seeds doesn't require any special skills, just a basic understanding of the flowering process and seed formation for each vegetable.
Some vegetables produce seeds in a fleshy fruit, such as watermelon and tomato.
The seeds can be extracted by scooping out the seed-laden flesh into a container. Allow this to ferment for a few days, and the good seeds will sink to the bottom. The flesh and the bad seeds will float on top. Pour the flesh and bad seeds off the top and add fresh water. Continue this process several times until only the clean seeds are left.