Northwest amaranth (Amaranthus) is a lettuce-like annual plant that's grown for its edible leaves and seeds that are used as grain crops in some countries. The protein-rich seeds are often ground into a flour that's mixed with cereal flours. The leaves can be eaten in salads or used as a cooking green, like spinach. Amaranth has colorful, usually bright-red or pink leaves and can grow up to 7 ½ feet tall. Amaranth is usually grown from seed, germinating easily and quickly. The amaranth leaves are ready for harvest in as little time as just six weeks after planting the seeds.
Plant your amaranth seeds outdoors in the ground in the spring, after all danger of frost has passed and the soil has warmed up to about 65 to 75 degrees Fahrenheit. Select a planting site that's in full to partial sunlight and has deep, well-draining soil.
Remove all weeds, grasses and other debris from the planting site. Loosen the soil bed to a depth of 6 to 12 inches using a pitchfork or rototiller. Spread a 2- to 3-inch layer of organic compost onto the soil bed and mix the compost into the top 6 inches of soil.
Plant the amaranth seeds ¼ inch deep and 4 to 6 inches apart. Water your amaranth seeds lightly and evenly to moisten the top 2 to 3 inches of soil every day until the seedlings begin to sprout.
Thin out the weakest seedlings after the seeds germinate and begin to sprout, so that the amaranth plants are spaced 12 to 18 inches apart. Water the seedlings about twice per week to keep the top 6 inches of soil evenly moistened but not wet.
Feed your amaranth plants a granular, high-nitrogen vegetable fertilizer once every two weeks, following the instructions on the label. Spread the fertilizer beside the amaranth, no closer than 4 inches to the plants.