Identifying edible wild greens

It can be, but only with very cautious identification. The cardinal rule is never eat anything you can't identify with absolute certainty, because some wild plants have toxic look-alikes that can make you seriously ill or worse. Start with a small number of common, unmistakable greens, learn them thoroughly, and build slowly. Beginner foraging is safe when you respect that uncertainty means you don't eat it.

Common, distinctive ones with few dangerous look-alikes, like dandelion, nettle, and chickweed. Dandelions are hard to mistake, nettles announce themselves by stinging, and these are widespread and well-documented. I'd avoid anything in the carrot/parsley family early on, since that family includes some of the most toxic plants there are, alongside edible ones. Begin with the easy, safe handful.

Multiple sources, and ideally a knowledgeable person. Use a good regional field guide, cross-check with reputable apps and websites, and learn from an experienced forager, a foraging walk, or a local group. Photos alone aren't enough, since many plants look similar, so learn the distinguishing features (leaf shape, smell, stem, habitat). Confirming with more than one reliable source before eating anything is the habit that keeps you safe.

Clean, unpolluted ground where foraging is permitted. Avoid roadsides (exhaust pollution), sprayed areas, industrial sites, and ground used by dogs, since plants absorb contaminants. Check local laws too, as foraging is restricted or banned in some protected areas and on private land. Pick from clean, safe locations, take only what you'll use, and leave plenty behind.

Wash them well, and cook the ones that need it. Rinse thoroughly to remove dirt and insects, and know which greens must be cooked, since nettles, for instance, must be cooked or thoroughly dried to neutralise their sting. Some wild greens are fine raw in small amounts, while others are better cooked or only safe cooked. Research each plant's preparation rather than assuming all greens are like salad leaves.

Don't eat it, full stop. This is the single most important rule in foraging: any doubt at all means you leave it. The downside of skipping an uncertain plant is missing a meal, while the downside of eating a misidentified one can be severe poisoning. Experienced foragers pass up plants they're unsure of all the time. Certainty isn't optional, it's the whole foundation of foraging safely.
⚠️ Never eat any wild plant unless you are completely certain of its identity. Some edible greens have toxic look-alikes that can cause serious illness or death. When in doubt, do not eat it.