This annual plant is 1-6' tall, branching occasionally. The stems are stout, angular, and variably colored, ranging from light blue-green to striped with purple and green. The upper surface of the lower leaves is usually green or bluish green and glabrous, while the lower surface may be glabrous to more or less white mealy with tiny white hairs. The inconspicuous yellowish green flowers are sessile against the flowering stalks and densely distributed. Each flower is about 1/10" across. The blooming period can occur from mid-summer through the fall, and lasts about 1-2 months for a colony of plants. The flowers are wind-pollinated.
Habitats include cropland, old fields, gardens, nursery plots, vacant lots, weedy meadows, construction sites, and miscellaneous waste areas, particularly where the soil has been recently disturbed. Lamb's Quarters does not invade high quality natural areas to any significant extent.
Lamb's Quarters is often dismissed as a mere weed, but it is an important source of food and cover to many kinds of insects and birds. The young leaves and stems can be added to salads (the taste is rather bland and dull), or they can be boiled as a potherb.