purple amaranth (Amaranthus cruentus), photographi

Can I Grow Purple Amaranth in New Mexico?

USDA Zones 5a-9a · Plant zone range 2-11

Yes — Strong Match

purple amaranth (zones 2-11) covers every zone New Mexico contains (5a-9a), so hardiness is not what limits it anywhere in the state.

Purple Amaranth in New Mexico — the short answer

Purple Amaranth in New Mexico: hardy in zones 2–11, full sun, against a state median of ~209 frost-free days.

Plant zones
2-11
Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
New Mexico zones
5a-9a
USDA PHZM 2023
Frost window
Mar 31 - Apr 19 – Oct 22 - Nov 9
NOAA RCC ACIS 1991-2020, 28°F
Shortest county season
144 days
NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
Days to maturity
90 days
Growable Ground Plant Database

Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.

Score your parcel · free

Your yard isn't the whole zone.

Purple Amaranth is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical New Mexico site runs ~209 frost-free days, but that is a state median, not your yard: slope, trees, and low spots move the last-frost date across a single parcel. Enter your address and we'll score purple amaranth against your land's actual frost dates, sun, and soil.

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New Mexico is not one climate

A single New Mexico answer averages 33 counties whose growing seasons are 120 days apart — from 144 frost-free days in Catron County to 264 in Doña Ana County. Which end of that your land sits nearer changes what purple amaranth can finish before the first hard freeze.

144 daysCatron County264 daysDoña Ana County

The middle half of 33 counties runs 186221 days, with a median of 209 days — a 120-day span end to end.

Measured across 33 New Mexico counties. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.

Where in New Mexico Fits Best

Even within New Mexico's zones 5a-9a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for purple amaranth (USDA PHZM 2023):

Zone Comparison

Purple Amaranth Needs

  • USDA Zones: 2-11
  • Frost-Free Days: 30+
  • Sun: Full Sun
  • Mature size: 5 ft tall
  • Picking window: ~30 days of harvest
  • Drought tolerance: High

New Mexico Has

  • USDA Zones: 5a-9a
  • Last Hard Freeze (28°F): Mar 31 - Apr 19
  • First Hard Freeze (28°F): Oct 22 - Nov 9
  • Annual Rainfall: 8-20 inches
  • Common Soils: Sandy loam, Caliche, Adobe clay

Plant Zone Range (zones 2-11)

2a
11b
3a (Cold)13b (Hot)

Preferred Soil pH

3.5 (Acidic)7.0 (Neutral)9.0 (Alkaline)
Highlighted range: pH 4.37.5

Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.

When to Plant Purple Amaranth in New Mexico

The frost window

Across New Mexico, the last spring hard freeze (28°F) clears between Mar 31 and Apr 19, and the first fall hard freeze lands between Oct 22 and Nov 9 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 186-day window you can count on — up to 223 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.

Frost tenderness

Purple Amaranth is frost-tender — FAO ECOCROP puts its killing temperature at 32°F — so set plants out two to three weeks PAST your local last hard freeze, not on it and not on the state's earliest date. The 28°F marker above is when killing freezes stop, not when light frost does. That is the point where cold damages growing tissue, not a winter-survival floor — an established perennial comes through far colder while dormant, which is what its hardiness zone tells you.

When to start the seed

Those dates are when purple amaranth goes out, not when it starts. It is sown under cover about 4 weeks ahead, so counting back from New Mexico's late-side last freeze of Apr 19 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.

Days to maturity vs. the window

At 90 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 96 days to spare even in New Mexico's tightest freeze scenario — room for a later start or a second sowing.

Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.

Growing Season Fit

The zone check says purple amaranth survives winter here. Whether the season is long enough — and warm enough — is a different question.

Frost-free days

Purple Amaranth wants 30+ frost-free days; a typical New Mexico site sees ~209 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.

Growing degree days

Purple Amaranth needs ~1500 GDD (base 50°F) to ripen. The state median runs ~2899 GDD (from PRISM 1991-2020 climate normals), so New Mexico's typical season clears that easily.

GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.

Soil + Drainage Fit

Purple Amaranth tolerates a wide pH range (pH 4.3-7.5) — 3.2 units, acid ground through alkaline — so soil acidity is rarely what limits it in New Mexico. A soil test is still worth having, but for what else it tells you about this site, not to clear this plant. It will grow across that whole span, but it does best between pH 5.5 and 7 — worth knowing before you decide whether a New Mexico soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your New Mexico site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.

Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. New Mexico soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.

What Else to Consider for Purple Amaranth in New Mexico

Zone compatibility tells you about winter cold survival — but New Mexico growers also need to think about:

Very low rainfall requires irrigation for most crops

High altitude UV intensity can burn tender transplants

Alkaline soils limit plant selection without amendment

What to actually do about these — and the constraints that apply to every New Mexico grower, not just purple amaranth — is covered on the New Mexico growing guide.

Timing shifts within New Mexico

Purple Amaranth needs about 30 days of frost-free season to complete its cycle. Even Catron County — New Mexico’s shortest season at 144 frost-free days — clears that by 114 days, so season length isn’t the constraint anywhere in New Mexico. What varies is your own parcel.

Across New Mexico’s 33 counties the frost-free season runs from 144 days in Catron County to 264 days in Doña Ana County — a spread of 120 days, which is why a single statewide planting date misleads. The median New Mexico county sees 209 frost-free days, leaving purple amaranth about 179 days of slack on a typical parcel — room for a second sowing where the season runs long.

County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). Purple Amaranth's 30-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.

New Mexico Cooperative Extension

For New Mexico-specific cultivar recommendations, planting calendars, and pest pressure for purple amaranth, the canonical source is NMSU Cooperative Extension Service. Their fact sheets carry the local trial data we can't generalize across 50 states.

Is Purple Amaranth native to New Mexico?

No — the USDA PLANTS Database lists Purple Amaranth as introduced rather than native in the Lower 48, so it is not part of New Mexico's native flora. It grows here as a garden plant; pairing it with a few New Mexico natives keeps local pollinators fed too.

Looking for plants that belong here? The New Mexico growing guide lists USDA-documented natives for the state.

Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.

Common Questions About Growing Purple Amaranth in New Mexico

When can I plant Purple Amaranth in New Mexico?

New Mexico's last spring hard freeze (28°F) clears between Mar 31 and Apr 19, and the first fall hard freeze lands between Oct 22 and Nov 9 (NOAA Regional Climate Centers ACIS, 1991-2020). Purple Amaranth is frost-tender — its killing temperature is 32°F (FAO ECOCROP — the point where cold damages growing tissue, not a winter-survival floor) — so wait two to three weeks past your site's last hard freeze, when light frost has also stopped, before planting out.

Can Purple Amaranth mature before first frost in New Mexico?

Yes — Purple Amaranth matures in 90 days (Growable Ground Plant Database), and New Mexico's dependable hard-freeze-free window runs 186 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 96 days of margin. Plant once the last hard freeze has passed — two to three weeks later for anything tender — and it ripens ahead of the first fall freeze.

What hardiness zone is Purple Amaranth grown in across New Mexico?

New Mexico spans USDA hardiness zones 5a-9a (USDA ARS PHZM 2023). Purple Amaranth carries a range of zones 2-11, so the overlap zones are where outdoor growing is most reliable.

How many frost-free days does a typical New Mexico site have?

A typical New Mexico site sees ~209 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Purple Amaranth needs 30+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.

Is Purple Amaranth native to New Mexico?

No — the USDA PLANTS Database lists Purple Amaranth as introduced rather than native in the Lower 48, so it is not part of New Mexico's native flora. It grows here as a garden plant; pairing it with a few New Mexico natives keeps local pollinators fed too.

How should I amend the soil for Purple Amaranth in New Mexico?

Purple Amaranth tolerates pH 4.3-7.5 and well (dry spells) drainage (FAO ECOCROP). That is a 3.2-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a New Mexico site — amend for drainage and organic matter first.

Will Purple Amaranth actually grow on my specific land in New Mexico?

State-level zone + climate data is a sketch. A Growable Ground parcel report scores purple amaranth against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.

Free Report

Check your specific parcel in New Mexico

State-level data is a sketch. Your Growable Ground report scores purple amaranth against your parcel's exact soil, sun, drainage, and frost data — not zone averages.

Three things about your lot that New Mexico purple amaranth averages can't show:

Your soil pHYour frost-free days — New Mexico averages 209Your sun & shade

We read public map data around New Mexico — soil, climate, flood, and parcel records. How we handle your address.

25+ data sources read at your address, not the New Mexico purple amaranth average

Explore More

Explore New Mexico county by county

New Mexico carries 33 counties with their own USDA zone — a sample of the growing pages for purple amaranth there:

Where else purple amaranth grows

Purple Amaranth's zone band crosses state lines — these are the states closest to New Mexico in winter climate where it also has a page, plus the far ends of its range. Each one re-answers the question with that state's own record.

More to grow in New Mexico

New Mexico has a growing page for 1,038 plants — a rotating sample of the rest of the shelf.

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