Edible Weed Worries
Why eat "weeds" at all? A lot of our vegetables are closely related to "weeds" or have been bred from these wild plants eg. broccoli comes from wild mustard (see below). The original plant often has a higher nutrient content than the supermarket version and they are so much easier to grow!
Some of your concerns may be: difficulty in correctly identify edible weeds, concern about naturally occurring toxins or exhaust from cars on a busy street, fear that they might have been sprayed, or that dogs might have been there before you.
These concerns are valid. You need to know what activities occur in those areas where delicious looking weeds are growing. Many edible weeds as well as other vegetables (spinach, celery, rhubarb) do contain oxalic acid. The advice would be to, eat weeds in moderation! A good website is http://www.eatthatweed.com/oxalic-acid/
I have been researching and collecting edible weeds for 15 years. Initially, I took specimens to a botanist, bought multiple books on the topic, went on weed foraging tours and talked to lots of elderly Greek women who have a wealth of knowledge on the topic. You must identify the weed before you eat it. On the whole, you are safer foraging for leafy greens than for mushrooms. I actually joined a fungi association in Vancouver but decided that fungi foraging was too risky for me. The consequences of getting it wrong, with fungi, tend to be much worse than for leafy greens. Consult http://www.eatthatweed.com/
Field Mustard (Brassica Rapa)
The leaves and shoots are very similar to broccoli. They have quite a strong turnip flavour and go well in curries, soups and stews.
Field mustard goes particularly well in a Chicken casserole, Biryani, Asian stir fry and Cauliflower cheese
Sow Thistle (Sonchus)
Sow thistle is the perfect spinach replacement and is found in many gardens in Autumn and Winter. It has a mild flavour and is one of the most versatile edible weeds. I particularly like thistle leaves in spinach triangles, frittata, pesto spinach pasta, lasagne, and spaghetti and pasta sauce. Actually, put some in any recipe!
Purslane (Portulacca Oleracea)
I first heard about purslane from a lecturer at Monash Uni who was served purslane in a salad in Greece, and she was raving about it. Purslane has a mild flavour and goes very well in a Greek salad. It is also good in a pasta salad, bok choy salad and chicken waldorf salad. Purslane is high in omega 3 fats which is a bonus. Being a succulent, it tends to grow better in sandy soils in summer. I have seen this weed in many countries.
Stinging Nettle (Urtica Dioica)
If you google "stinging nettle soup" you will get thousands of hits. Collect them with tongs and scissors to avoid being stung. As soon as they are plunged into boiling water, the sting disappears. They have a mild flavour. I remember camping near a patch of nettles and we had a can of soup but no vegetables. So, nettles were the answer to a delicious soup that fed more people.
Nettles go well in congee, minestrone, shepherd's pie, biryani, lasagne, macaroni cheese, tofu hot pot. They go well in anything. Experiment.
Mallow (Malva Neglecta)
I first heard about mallow from a Greek patient who used to cook mallow with rice. Chop the leaves and add them to rice (cooked by the absorption method). Mallow has a mild flavour and is excellent for adding to many of the dishes on this website. Try in soups (congee, minestrone), biryani, chicken casserole, macaroni cheese, baked risotto
Pigweed (Amaranth)
I first came across this plant while talking to a Greek lady who gave me some seedlings. It comes up at the beginning of summer and I often see it growing on the side of the road. It as a mild flavour, making it suitable to add to most of the main meals on this website. Greek people often saute it with olive oil and lemon juice. The seeds are edible but I think they are a bit small to bother with. Try in soups (congee, minestrone), biryani, chicken casserole, macaroni cheese, baked risotto
Sea celery (Apium Prostratum)
If only this plant grew in other places other than by the sea! It replaces celery and is very tasty in any soups, chicken casserole, shepherd's pie, lasagne, macaroni cheese, spaghetti and pasta sauce, tofu hot pot. Experiment with a handful of chopped sea celery.
Black Nightshade (Solanum Nigrum)
It's OK. Yes, it's nightshade but not deadly. Other plants belonging to the nightshade family are potatoes, tomatoes and eggplants. The actual "deadly nightshade's" botanical name is atropa belladonna which is in a different genus. The leaves of Black Nightshade are a great spinach substitute. The berries can be eaten when ripe but I have only used the leaves. It is commonly used in cooking in South Africa which is where I was introduced to it. Try in soups (congee, minestrone), biryani, chicken casserole, macaroni cheese, baked risotto