How to Grow Ruby Giant Amaranth
iNaturalist
Ruby Giant Amaranth
Amaranthus cruentus
vegetableRuby Giant is a striking ornamental and edible amaranth variety known for its deep red, burgundy foliage and grain-like seed heads. It produces nutritious grain and vibrant edible leaves that can be used fresh or cooked. This heat-loving annual plant is prized for both its visual appeal in gardens and its high nutritional value.
When should you plant Ruby Giant Amaranth in your zone?
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Example Ruby Giant Amaranth timeline · Pittsburgh, PA (Zone 6b)
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Plant Ruby Giant Amaranth
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Ruby Giant Amaranth
Around Jun 26≈ 70 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Ruby Giant Amaranth dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 5-11; can be grown as annual in zones 3-4
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Seedling
2-3 weeksTiny seeds germinate into delicate plants with true leaves appearing within 1-2 weeks; initial foliage is green to reddish.
Keep soil consistently moist but not waterlogged. Thin seedlings to proper spacing once 2-3 inches tall. Protect from frost.
Vegetative Growth
4-6 weeksPlant develops robust stems and increasingly vibrant deep red to burgundy foliage; can reach 4-6 feet tall depending on variety.
Water regularly and deeply. Provide full sun for best color. No staking needed but tall plants may benefit from shelter from high winds.
Flowering/Heading
2-3 weeksDense, upright flower panicles emerge from the top and leaf axils, ranging from dark burgundy to deep crimson.
Continue consistent watering. The plant's red color intensifies. Flowers are tiny but abundant.
Grain Maturation
3-4 weeksFlower heads dry and harden; seeds develop and become visible as tiny spheres within the panicle.
Reduce watering slightly. Heads may continue darkening. Watch for seed head maturity.
Harvest Ready
Ongoing through frostSeed heads are fully dry and brittle; foliage may begin to yellow. Seeds detach easily when rubbed.
Allow to fully dry on plant if possible. Cut heads when completely mature for best seed yield.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Hand-pick insects and egg clusters. Neem oil spray if populations are high. Remove affected leaves.
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Increase humidity; spray undersides of leaves with water. Neem oil or insecticidal soap for severe infestations.
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Remove affected leaves and flowers. Bacillus thuringiensis (Bt) spray for severe cases.
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Row covers for young plants. Neem oil or kaolin clay spray.
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Strong water spray to dislodge. Insecticidal soap or neem oil if persistent.
Uses
Grain & Seed Source
CulinaryRuby Giant seeds are nutrient-dense and can be popped like popcorn, cooked as porridge, or ground into flour for baking. High in protein, fiber, and minerals. [source]
Edible Leafy Greens
CulinaryYoung leaves and shoots can be eaten raw in salads or cooked like spinach. They are mild, tender, and highly nutritious with a slightly earthy flavor. [source]
Nutritional Supplement
MedicinalAmaranth is gluten-free, high in complete protein with all essential amino acids, and rich in calcium, iron, and magnesium. Traditionally used to support bone and heart health. [source]
Ornamental & Cut Flower
CraftThe striking deep red flower and seed heads are stunning in fresh or dried flower arrangements, floral designs, and as dried botanical specimens. [source]
Bird & Pollinator Food Source
WildlifeSeeds attract finches, sparrows, and other birds; flowers draw bees and beneficial insects. Excellent late-season food source for wildlife. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
For leaves: Harvest continuously once plant is 6-12 inches tall by pinching off tender upper growth or cutting outer leaves; plant will bush out. For grain: Allow seed heads to fully mature and dry on the plant (usually 100+ days after planting). Cut mature heads, allow to air-dry indoors for 2-3 weeks, then rub heads over a screen or cloth to separate seeds. Store dried seeds in a cool, dry place.
Fun Facts
- 🌱 Ruby Giant amaranth was one of the staple grains of the Aztec civilization and remains a sacred crop in some Mesoamerican cultures.
- 🌱 The name 'amaranth' comes from the Greek word 'amarantos' meaning 'unfading flower,' because the flowers retain their color even when dried.
- 🌱 Amaranth is technically a pseudocereal (not a true grain), but nutritionally surpasses many grains with its complete amino acid profile and higher protein content.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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