No pictures yet- I'm OK with being lazy- and they won't be helpful when they are up. :-)
This is meant to be a less-helpful, more limited version of Peterson's. For garden plants. This is not intended to be an extensive volume, or decisive, but it should be able to tell you whether to pull or to keep a plant in your garden. Whether to eat, if something is edible- that's a whole other story. Hopefully, if you can key it out to something worth saving with this guide, it should at least be non-toxic, but I can't vouch for what you've been planting.
Sturdy stem, vaguely heart shaped leaves that are soon clipped off by wild life, to likely wither and die- The beans and peas that you were counting on for salads. Don't pull.
Broad leaves emerging from the soil with little to no stem, can be quite colorful and also prized by wild life- Those salad greens that you wanted for with the beans and peas. Don't pull.
Very common plant, reddish stem, two very long thin cotyledons- The universe's way of telling you that you should be in silviculture, not agriculture. Tree seedlings from the nearest prolific tree. Eat if you dare. Pull. Then cut down the source of the seeds in spite.
Fairly common plant, grown in sort of row-ish configuration- Don't pull. But a warning- this one will be the prime target of husbands and children trying to be helpful, so don't expect it to last.
Long thin leaves emerging from the ground with no stem- Grass. If it's a stiff leaf, with a prominent midrib, probably barn sedge. Pull. Not that it will do any good.
Oblong, circular or arrowhead shaped leaves on a petiole that emerges from the ground in small bunches- Spinach or plaintain (not the banana like one). Don't pull. But good luck trying to get your kid to eat it.
Random rocks, candy, and toys- You're in the Land of Oz. That section of garden that you let the kid(s) plant, in an attempt to get them interested. Back away, slowly. None of it will grow, and if you try to pick up the mess, there'll be h3ll to pay. Hey, don't we all wish growing your own candy were that simple?
Common plant, grown in rows, still has the tops intact- Don't pull, but know that the bugs are coming. Start trying to find alternative ways to keep bugs off plants now. Because I know you're growing an organic garden, right?
Long straight stem with leaves wrapped tightly around the stem, occurs sporadically in one specific area- The corn that the squirrels managed to not find and dig up. For the third time. Don't pull.
Delicate, almost fern-like leaf on a long petiole- Carrot, dill, or other probably edible. Don't pull.
For any other questions on plant identification, let them grow until you can identify them. You might get some veggies out of the deal, and at least you garden looks a little greener.