Grain Amaranth (Amaranthus hypochondriacus)
Also known as: Prince's feather · 10 sources cited · Verified
The short answer
- Plant
- Early April to early May
- Ready in
- 90–100 days
- Site
- soil pH 6.5–7.5
- Biggest risk
- Damping-off
In the UK, grain amaranths go in the ground early April to early May, and are ready to harvest 90–100 days after planting.
Grain amaranths (Amaranthus hypochondriacus) — Annual.
Timing is the decision that matters most in the UK: there are 4 separate regional sowing windows, ranging from early April in southern England to mid April further north.
Core growing advice on this page is checked against named horticultural and university-extension sources — see References.
Regional Planting Calendar
| Region | Sow |
|---|---|
| Southern England derived | early April to early May |
| Midlands derived | early April to mid May |
| Northern England derived | mid April to mid May |
| Scotland derived | mid April to late May |
Rows marked derived are interpolated between regions our sources do state, because no source we consulted gives a figure for that region specifically. They are deliberately wider to reflect that uncertainty.
Southern England - detail & sources
DERIVED: no hypochondriacus-specific UK source states a sowing window. Modelled on sister species A. caudatus's RHS-sourced mid-spring direct-sow guidance, adjusted for the earliest UK frost-free window per Met Office (southern/coastal regions' last air frost typically before April ends).
Midlands - detail & sources
DERIVED: interpolated a week later than southern England and a week earlier than northern England, following the same reasoning as the southern England row.
Northern England - detail & sources
DERIVED: modelled on sister species A. caudatus, adjusted later per Met Office's documented later last-frost dates further north.
Scotland - detail & sources
DERIVED: modelled on sister species A. caudatus; Scotland gets the latest sowing window in the UK for this frost-tender species per Met Office's frost-gradient data.
Quick Facts
| Factor | Value |
|---|---|
| Soil pH | 6.5 - 7.5 |
| Germination temp | 18C |
| Optimal growing temp | 19-23C |
| Minimum survivable temp | 0C |
| Time to harvest | 90-100 days |
| Soil texture | Loam preferred; adapted to a range of soils per genus-level RHS guidance |
| Drainage | Moist, well-drained, humus-rich |
| Lifecycle | Annual. |
| Edible parts | seeds, leaves |
At a Glance
Soil & Growing Conditions
Growth Stages
| Stage | Notes |
|---|---|
| Establishment | Propagate by seed (RHS genus guide); germinated better than A. cruentus at 12C in comparative trials, suggesting relatively better cool-soil establishment. |
| Vegetative Growth | Upright or spreading annual with simple leaves (RHS genus guide). |
| Flowering | Dense, erect or pendulous, catkin-like inflorescences in summer and autumn (RHS). |
| Fruit Development | Grain-type seed heads develop after flowering; A. hypochondriacus is one of the principal grain amaranth species. |
| Ripening / Harvest | Grain harvested once seed heads dry and thresh freely. |
| Senescence / Dormancy | Grown as a warm-season annual. |
Harvest & Storage
Diseases
Pests
What Grain Amaranth Looks Like, Season to Season
References
-
Tier 1. Best germination occurs when soil temperatures range from 65 to 75F (18-24C); seed ripens usually after about three months; shake flower heads gently to test if seeds fall readily
-
Tier 1. Survey of fungal diseases associated with amaranth in peri-urban vegetable farms in Ghana: wet rot, anthracnose, damping-off/wilting
-
Tier 1. Grain amaranth adapted to soils pH 6.5-7.5
-
Tier 1. Optimal temperature 19C, max 23C; killing temperature during early growth 0C
-
Tier 1. White rust/damping-off fungi Pythium aphanidermatum and Rhizoctonia affect amaranth seedlings; stem weevil and leaf caterpillar pests documented
-
Tier 1. Pests: tarnished plant bug (Lygus), flea beetle, amaranth weevil. Diseases: damping-off (Pythium and Rhizoctonia), stem canker (Phoma or Rhizoctonia). Grain amaranth plants about five to seven feet tall when mature.
-
Tier 1. Amaranthus hypochondriacus L. -- accepted name, Plants of the World Online
-
Tier 1. GBIF Backbone Taxonomy match, usageKey 9080185, status ACCEPTED
-
Tier 1. RHS genus guide: frost-tender annual; full sun, moderately fertile humus-rich moist soil, sheltered site
-
Tier 1. Amaranthus hypochondriacus L. -- WFO accepted taxon record wfo-0000530285
10 independent sources are cited for this crop. Where they disagree - soil pH is the clearest case - every figure is preserved rather than averaged into false precision.
Frequently Asked Questions
When should I sow grain amaranths in the UK?
In southern England, from early April. In northern England and Scotland, wait until mid April. Treat these as a guide rather than a fixed date — the governing rule is to sow only once frost risk has passed and temperatures are reliably warm enough.
When do I sow grain amaranths?
Sow early April to early May, at around 18°C for germination.
How long do grain amaranths take to grow?
Typically 90–100 days, depending on cultivar and growing conditions.
What soil pH do grain amaranths need?
A pH of about 6.5–7.5. That span reflects genuine variation between the authorities we cite rather than a single agreed figure — the References section lists each source's exact range.
What problems affect grain amaranths?
Our data links 4 diseases and 3 pests to this crop. See the sections above for each one and how to manage it.
Plan next season before the problems start
Most of the advice on this page comes down to timing and spacing — sowing at the right moment, rotating beds, and giving plants enough airflow. The UK Garden Planner lays your plot out month by month so those decisions are already made before the season starts.
Get the UK Garden Planner →Instant PDF download · Written for UK growing conditions
Last verified 2026-07-27
Tools That Help With This Crop
Use these links when the guide moves from reading into sowing, planting, watering, and keeping the crop healthy.
Plan the next step
Use the printable UK Vegetable Garden Planner to turn this guide into sowing dates, bed layouts, and weekly garden tasks.