While it is perfectly possible to eat the tiny plants growing in cement cracks, I typically only gather purslane when it is growing lushly in more desirable places. Vigorously growing purslane is not hard to find. The best parts are the new, rapidly growing tips before plants go to seed. By "best," I mean that they will work fine in your most delicate salads served to your most-finicky wild-food-fearing friends—and at fine restaurants everywhere. Gather the leafy stems—not just the leaves. Plucking the leaves individually would be the best way to procrastinate from doing anything important in your life. The leaves are too small to pluck except for specific purposes.
Some larger individual leaves can be used as a garnish. Kids love plucking the leaves. Lovers who are gambling on their relationship do the "she loves me, she loves me not" thing (daisies are good for that too). And remember, the stems are part of the food! Say this again to yourself: the stems are part of the food—a great part.
If you plan on using purslane as greens, either fresh or cooked, and you have lots of purslane to choose from, just collect the tips. The last inch or two of the leafy stems will be the most delectable. Why not? You can be choosy. If you can't find much purslane to gather, either let the plants go to seed for next year or collect whatever you can and use whatever you get.
While gathering, if you are thinning an area to allow something else to grow, pull purslane out by the roots. Be careful to keep all the root material together as you carefully stack them for transport. Doing this will help you in the cleaning process later.
Once collected, purslane travels well. Because it's a succulent, it does not wilt quickly; but it is still helpful to spray-mist your take unless you collect it with root material. Moistening the dirt on root material just makes a big mess. Keep harvested purslane cool until you can trim and wash it in cold water. Its solid structure makes it easy to clean. Use your harvest fast for the best quality.
For tips on preparing purslane, check out these cooking tips.
Excerpted from Edible Wild Plants: Wild Foods from Dirt to Plate by John Kallas, PhD Copyright © 2010. Excerpted by permission of Gibbs Smith. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.