>>2095850>Find a plant that is plentiful.You don't want to go through the rigorous process of testing a plant if there's not a lot of it to eat.
>Abstain from eating or drinking anything but purified water for 8 hours before the test.This way you avoid nasty reactions.
>Separate the plant into parts.Some plants have edible parts and poisonous parts. In order to test if a plant is edible, you must separate it into the leaf, stem, and root and test each part separately for edibility.
>Find out if the plant is contact-poisonous.A contact-poisonous plant is one that causes a reaction merely by touching your skin. Rub the selected plant part on the inside of your elbow or wrist. Crush it so that the sap touches your skin, and hold it there for 15 minutes. If the plant causes a reaction in the next 8 hours, do not continue testing that part of that plant. Do this with each part of the plant until you find a part that isn't contact-poisonous.
>Cook a small portion of the plant part.Some plants are poisonous only when raw, so it's a good idea to cook the plant part you are testing if possible.
>Test the plant in your mouth.Hold a small portion of the prepared plant part against your lip for 3 minutes. Do not put the plant in your mouth. If you notice any burning, tingling, or other reaction, discontinue testing. Place another small portion of the plant part on your tongue. Hold the plant on your tongue without chewing for 15 minutes. Discontinue testing if you notice any reaction. Chew the plant and hold it in your mouth for 15 minutes. Chew the plant well, and do not swallow. Discontinue testing if you notice any reaction. If nothing of the above happens, swallow the small portion of the plant.
>Wait 8 hours.Do not eat or drink anything during this period except purified water. If you feel sick, immediately induce vomiting and drink plenty of water.
This is a copy/paste. You can find more here:
https://www.wikihow.com/Test-if-a-Plant-Is-Edible 