A fast-growing, heat-loving plant grown for its nutritious leaves, striking seed heads, and high-protein grain — productive in poor soils where many crops struggle.
Amaranthus cruentus · also called red amaranth, purple amaranth
Windows are counted from the average date of your last spring frost.
Amaranth tolerates drought and high heat that stall most leafy greens, delivering edible leaves within weeks and a substantial grain harvest by season's end. Both the leaves and seeds are nutritionally dense, with the grain containing a complete amino acid profile uncommon in plant foods.
A little history. Native to Mesoamerica and cultivated there for at least 6,000 years according to archaeological evidence. Amaranthus cruentus is a C4 plant, meaning it uses a photosynthetic pathway that is especially efficient at converting sunlight and CO2 to biomass under high temperatures.
Sow seeds ¼ inch (6 mm) deep, and aim for 18 inches (45 cm) between plants once thinned. Press seeds into the top ¼ inch of soil — they need light to germinate. Keep the seedbed evenly moist until sprouts appear. Seedlings emerge in 5–10 days.
Water deeply once or twice a week; reduce once plants exceed 12 inches tall. Water when the top 2 inches of soil feel dry. Aim for about 1 inch per week; established plants tolerate short dry spells.
Side-dress (scatter fertilizer along the row and water in) once at 6 inches tall; avoid heavy feeding after that. What to use: balanced 5–5-5 organic or compost — excess nitrogen pushes leaf growth at the expense of seed heads.
Pinch out the central growing tip when plants reach 12 inches to encourage branching and more seed heads on leaf or multi-harvest types. Skip pinching on grain types grown for a single large central plume.
It's ready when leaves: harvest young leaves at 6–8 inches long before the plant flowers. Grain: seed heads are ready when seeds release easily when rubbed between fingers and the plume begins to dry and fade. Leaves: snip outer leaves with scissors, leaving the growing center intact. Grain: cut entire seed heads into a paper bag when 80% of the plume is dry; hang upside down in a warm, airy space for 1–2 weeks, then thresh by rubbing heads over a screen.
Fresh leaves: refrigerate in a damp cloth up to 5 days. Dried grain: store in an airtight container in a cool, dry place for up to 1 year.
For a continuous leaf harvest, sow a new short row every 3 weeks from last frost through midsummer.
Sweet Corn
Amaranth's dense plumes often pull tarnished plant bugs and other sap-feeders onto themselves and away from a neighbouring corn patch. A trap only pays off if you check the seed heads weekly and knock the bugs down or pull the worst plants before they breed.
Onion
Onions feed from a shallow mat of roots in the top few inches while amaranth sends a taproot well below them, so the two draw water and food from different layers. Narrow onion tops also cast almost no shade on young amaranth.
Bell Pepper
A row of amaranth on the west side can throw light afternoon shade over peppers, which often drop blossoms above 90F and scald on exposed fruit. Keep it 2 feet off so the peppers still get full morning sun.
Sweet Potato
Sweet potato vines run flat across the ground, shading the soil, holding moisture, and crowding out weeds while amaranth climbs straight up above them. Give amaranth an 18-inch clear circle so the vines do not swamp young seedlings.
Fennel
Fennel roots release substances that stunt most garden vegetables, and young amaranth seedlings are easily checked. Grown in its own corner well away from the beds, fennel earns a place — its flat flower heads feed hoverflies and tiny parasitic wasps that hunt aphids.
Give the beet family 2 years away from this spot before any of its relatives return.
The pea and bean family, the tomato family or the onion family thrive in this ground next season.
Amaranth is a moderate feeder that leaves behind little more than a deep taproot channel and loose soil. Keep the beet family — beets, chard, spinach, and amaranth itself — out of this bed for 2 years. Follow with peas or beans, then tomatoes or peppers, or an onion-family crop.
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