Opium plants are an erect, herbaceous annual, varying much in the colour of its flowers, as well as in the shape of the fruit and colour of the seeds. All parts of the plant, but particularly the walls of the capsules, or seed-vessels, contain a system of laticiferous vessels, filled with a white latex. The flowers vary in colour from pure white to reddish purple. In the wild opium plant, they are pale lilac with a purple spot at the base of each petal.

The opium plant likes altitudes above 850 meters near limestone ridges or below cliffs (Thailand). Fields are cleared early in the hot season (March) and burnt. Then a fast-growing crop like corn is planted. The poppy is sown in September and plants thinned out in November.

Vegetables are grown to add minerals to the soil as well as supplement the diet. They also help to hide the opium plants. The vegetables are cleared and the plants begin to flower in January. When the petals drop off the pods, farmers slit them in a way that causes the resin to ooze out and congeal on surface. The sticky congealed opium is scraped off a day later.