Amaranthus (Amaranthus Hypochondriacus Green Thumb) - This is a smaller Amaranthus plant growing 18 - 24 inches tall. It establishes nicely from flower seed. Green Thumb is a hardy annual, and it makes an excellent bedding plant. It prefers a sunny dry spot with well-drained soil.
Versatile annual plant
This Amaranthus is suitable for flower beds and does well in borders. The apple-green color goes well with most other colors and is a useful plant for filling in gaps in borders. It also is suitable for cutting and works well in arrangements.
Amaranthus Green Thumb has an upright shape. It has oval foliage that is dark green. It produces flowers during summer and autumn that are spikes in shape and green in color. It requires a moist, rich and well-drained soil, preferring full sun, and a position in a border, or it works well in a container.

SOWING
Season: Annual
Height: 50 cm (18 - 24 inches)
Bloom Season: Mid summer to autumn
Bloom Color: Green
Environment: Full sun
Soil Type: Well-drained, pH 6.1 to 6.5
Germination temperature: 18 - 23C (65 - 75F)
Average Germ Time: 10 - 21 days
Light Required: Yes
Depth: Press seed into soil, do not cover
Moisture: Keep moist until germination
Plant Spacing: 40 cm (18 - 24 inches) 

Amaranthus seed  'green thumb'
How To Grow Amaranthus From Seed: You can sow indoors approximately 6 weeks before frost season is over and transplant outdoors when temperatures are warming. Grow in loam-based potting compost in full light. Water freely in summer, and provide high humidity if possible.
Outdoors, sow Amaranthus seeds after frost season is over and night time temperatures are staying in the upper 5C (40F). Grow in moderately fertile, humus-rich, moist soil in full sun in a sheltered site. Amaranthus Caudatus will tolerate poor soil. Water freely during dry periods in summer to prolong flowering.