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When to Plant Basil in Los Alamos County, NM

Los Alamos County, New Mexico Zone 6a April

What to do in April

Here's what deserves your attention in Los Alamos County, New Mexico this month. Everything below is tailored to Zone 6a and timed around your local frost dates.

Avg. last frost May 10
Avg. first frost October 7
Soil temp (4") 38°F
Watering Critical
Pest pressure Low
Daylight 12.9 hrs
Looking ahead to May
  • Transplants going out: basil
  • Direct-sowing: basil

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Basil is a fragrant warm-season herb essential to Italian and Thai cuisines. It comes in many varieties including sweet, Thai, purple, and lemon types.

Los Alamos County, New Mexico is in USDA Zone 6a. The average last spring frost is May 10 and the first fall frost is October 7, giving you a growing season of approximately 150 days.

At an elevation of 5,220 feet, Los Alamos County receives approximately 12.1 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 87°F, providing good warmth for Basil during the growing season. Sandy soil warms quickly in spring — great for early planting — but Basil will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Basil successfully. Mulch heavily to conserve soil moisture.

Los Alamos County, NM (Zone 6a) Moderate season
150 days
Last Spring Frost May 10
150 growing days
First Fall Frost October 7
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Los Alamos County Soil Profile

Soil Type

Sandy Loam

Soil pH

7-8.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (16 days to spare)
Start indoors: Mar 14 Transplant: May 16 🍅 Harvest: Jul 11 – Sep 12
Recommended (50%) ✓ Fits season (17 days to spare)
Start indoors: Mar 22 Transplant: May 24 🍅 Harvest: Jul 19 – Sep 20
Safe Start (90%) ✓ Fits season (17 days to spare)
Start indoors: Apr 7 Transplant: Jun 9 🍅 Harvest: Aug 4 – Oct 6

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Los Alamos County

How your county's soil matches Basil's growing requirements.

Soil pH

Your soil pH (7.0–8.6) is more alkaline than Basil prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Los Alamos County warms quickly in spring but drains fast. Basil will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Basil.

Organic Matter

Organic matter is low (0.8%). Add 2-3 inches of compost before planting Basil.

How to Plant Basil

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Basil

3
successive plantings in your 150-day season

Sow every 5.7 weeks. Last sowing by Jul 24 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.3″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 707 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Basil

Basil needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Basil Needs Rainfall You Supplement Action
Jan 0.9" 0" ❄️ Dormant
Feb 0.6" 0" ❄️ Dormant
Mar 0.8" 0" ❄️ Dormant
Apr 0.4" 0" ❄️ Dormant
May 2.6" 0.3" 2.3" 🚿 Regular watering
Jun 2.6" 0.4" 2.2" 🚿 Regular watering
Jul 2.6" 1.9" 0.7" 💧 Light watering
Aug 2.6" 2.4" 0.2" 💧 Light watering
Sep 2.6" 1.7" 0.9" 💧 Light watering
Oct 2.6" 1.1" 1.5" 🚿 Regular watering
Nov 0.7" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Los Alamos County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Basil Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Basil needs ~953 GDD — county provides 2,287 GDD Excellent fit

Basil Planting Timeline — Los Alamos County, NM

Basil Planting Calendar

Activity When Date Range
Start Indoors March 22 Mar 22 – Apr 5
Transplant Outdoors May 24 May 24 – Jun 7
Direct Sow May 17 May 17 – Jun 7
Harvest July 19 Jul 19 – Sep 20

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Harvest
August Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · 1-2 times/week

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

150 days in Los Alamos County

Growing Tips for Basil in Los Alamos County

Direct sow Basil outdoors after May 10 in Los Alamos County when soil has warmed and frost danger has passed.

Sandy soil in Los Alamos County dries quickly — mulch Basil with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

General growing tips

Start seeds indoors or direct sow after last frost. Pinch flower buds to extend leaf production. Harvest leaves from the top down, cutting just above a leaf pair.

Companion Planting

Good Companions

Avoid Planting Near

  • Rue
  • Sage

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Basil Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let flower spikes dry brown on the plant.
Storage Store airtight; viable 5 years at 35°F, under 45% humidity.

Isolate 150 ft between varieties. Different basil species can cross.

Frequently Asked Questions

When should I plant Basil in Los Alamos County, NM?

Los Alamos County is in Zone 6a with an average last frost of May 10. Plan your Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Los Alamos County, NM?

Los Alamos County, New Mexico is in USDA Hardiness Zone 6a. The average last spring frost is May 10 and first fall frost is October 7.

🌱

Your Los Alamos County Garden Planner — Free

A 24-page printable planner built for Los Alamos County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Los Alamos County, NM. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.