Union County, NM — Planting Guide
What to do in June
We've pulled the most time-sensitive tasks for Union County, New Mexico this June and put them front and centre. Tackle them in order.
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Get basil, cucumber, and kale seeds going inside
These need a head start before your last frost (April 30). Sow into cells now so you're ready to transplant in a few weeks.
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Harvest carrots, kale, and lettuce as they ripen
The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.
Get ahead of July
- Starting indoors: peppers, astilbe, and begonias
- First harvests: basil, carrots, and cucumber
- Fall sowing: carrots, kale, and lettuce
Union County is in USDA Zone 6b. The average last spring frost is April 30 and the first fall frost is October 9, giving you a growing season of approximately 162 days.
At an elevation of 6,384 ft, Union County receives approximately 17.5 in of rainfall annually. Summer highs average 85°F with winter lows around 16°F. The predominant soil type is Sandy Loam.
Based on 31 years of NOAA climate station data, the last frost date here varies by 31 days year to year — ranging from April 16 in warm years to May 17 in cold years. Union County scores 36/100 (Challenging) on the Microclimate Index.
🌡️ Zone
6b (-5°F to 0°F min)
❄️ Last Frost
April 30
🍂 First Frost
October 9
📅 Growing Season
162 days
⛰️ Elevation
6,384 ft
🌧️ Annual Rainfall
17.5 in
Monthly Watering Calendar for Union County
When you'll need to water your garden — based on average monthly rainfall vs. the ~1 inch/week most gardens need.
The practical takeaway: A drip irrigation system pays for itself in 1-2 seasons in any climate. Union County's 18" annual rainfall determines whether you'll run it weekly (dry zones) or maybe just during summer dry spells (wet zones).
View detailed monthly data
| Month | Avg Rainfall | Rainy Days | Extra Water Needed | Watering Effort |
|---|---|---|---|---|
| Jan | 1.1 in | 2 days | — | None |
| Feb | 0.9 in | 3 days | — | None |
| Mar | 1 in | 2 days | — | None |
| Apr | 0.6 in | 1 days | 3.7 in | Critical |
| May | 0.4 in | 1 days | 3.9 in | Critical |
| Jun | 0.6 in | 1 days | 3.7 in | Critical |
| Jul | 3 in | 7 days | 1.3 in | Moderate |
| Aug | 4 in | 9 days | 0.3 in | Low |
| Sep | 2.1 in | 5 days | 2.2 in | High |
| Oct | 1.4 in | 2 days | 2.9 in | High |
| Nov | 1 in | 2 days | — | None |
| Dec | 1.3 in | 3 days | — | None |
Annual total: 17.4 in. Water needs vary by crop — tomatoes need ~1.2"/week while herbs like rosemary need only 0.3"/week. Check individual plant pages for crop-specific water budgets that factor in your county's rainfall and soil drainage.
Union County Soil Profile
Soil Type
Sandy Loam
Soil pH
6.9-8.3
Drainage
Well Drained
Frost Risk Probability
Based on 31 years of NOAA weather station data from 3 stations
Beginners: Plant frost-sensitive crops (tomatoes, peppers, squash) after the "Safe" date on the left. Harvest or cover them before the "Protect by" date on the right. Hardy crops (lettuce, peas, kale) can go in the yellow transition zones.
How to read this table: "Conservative" means you're safe from frost 9 out of 10 years — best for beginners and frost-sensitive crops. "Average year" is the typical date. "Aggressive" means only 1 in 10 years is that warm — experienced gardeners with frost protection can try these dates.
| Planting Strategy | Last Spring Frost | First Fall Frost | Frost-Free Days |
|---|---|---|---|
| Conservative (safest) | May 17 | Oct 24 | 160 days |
| Cautious | May 8 | Oct 14 | 159 days |
| Average year | Apr 30 | Oct 9 | 162 days |
| Optimistic | Apr 25 | Oct 5 | 163 days |
| Aggressive (risky) | Apr 16 | Sep 23 | 160 days |
Not very — frost dates can vary by ±31 days year-to-year. Use the "Conservative" row in the table below, and keep row covers handy for surprise late frosts.
Gardening Difficulty Score
Union County has challenging growing conditions. Season extension and careful variety selection are essential.
Local Gardening Help in Union County
Free expert help is closer than you think. Your county's cooperative extension office connects you with trained gardeners, soil testing labs, and local programs — all specific to Union County's climate and soil.
County Extension Office
Union County New Mexico State University Extension Extension Office
Phone: 575-646-3015
Visit Extension Office Website →
Extension offices are run by land-grant universities and funded by the USDA. Their advice is free, research-based, and tailored to your county's specific conditions.
Master Gardener Program
Free gardening help from trained volunteers
Master Gardeners are community volunteers who complete 40–60 hours of university horticultural training. They answer gardening questions, diagnose plant problems, and offer workshops — all free.
Many extension offices run a Master Gardener hotline where you can call or email with photos of plant problems for free diagnosis.
Soil Testing
Available through your extension office
Before amending your soil, get it tested. Your extension office offers soil testing (typically $10–$25) that tells you exact pH, nutrient levels, and amendment recommendations specific to what you want to grow.
Services Available in Union County
Finding local nurseries & garden centers in Union County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Union County's soil and climate that big-box stores can't. Plants from local growers are typically hardier because they're already acclimated to your zone.
How to Find Them
Search for "nurseries near Union County NM" or "garden center Union County" on Google Maps. Also check with your extension office — they often maintain lists of reputable local nurseries and plant sales.
Community gardens & gardening groups
Community gardens are a great way to learn from experienced gardeners in your area, especially if you're limited on space. Search "community garden Union County NM" or check your extension office and local parks department. Facebook groups like "Union County Gardeners" or "New Mexico Gardening" are also excellent for local advice and plant swaps.
What to Plant After Your Harvest
After your first crops finish, use the remaining frost-free days to grow a second round.
Show 6 more succession options
Sunlight & Day Length in Union County
Monthly daylight hours and peak sun — critical for onion varieties, photoperiod-sensitive plants, and solar garden planning.
Quick context: Photoperiod-sensitive crops will fail spectacularly if planted at the wrong latitude. Sweet onions in Michigan? Tiny. Spanish onions in Florida? Tiny. Match variety to Union County's daylight pattern and you'll see the difference.
Longest Day
14.5 hours
Summer solstice daylight
Shortest Day
9.5 hours
Winter solstice daylight
Peak Sun Hours
12.8 hr/day peak (summer)
Peak sun hours (green dashed line below) account for cloud cover — this is the usable direct sunlight your garden actually receives. Most vegetables need 6+ peak sun hours.
Onion tip: Day-neutral onion varieties like Candy, Cabernet, and Sierra Blanca perform best in your day-length range.
View detailed monthly data
| Month | Daylight Hours | Peak Sun Hours | Day Length |
|---|---|---|---|
| January | 9.8 hr | 6.9 hr | Short day |
| February | 10.7 hr | 7.8 hr | Short day |
| March | 11.7 hr | 8.8 hr | Short day |
| April | 12.9 hr | 10.9 hr | Neutral |
| May | 13.9 hr | 11.9 hr | Neutral |
| June | 14.5 hr | 12.8 hr | Long day |
| July | 14.3 hr | 11 hr | Long day |
| August | 13.4 hr | 9.7 hr | Neutral |
| September | 12.2 hr | 9.8 hr | Neutral |
| October | 11 hr | 9 hr | Short day |
| November | 10 hr | 7.6 hr | Short day |
| December | 9.5 hr | 6.5 hr | Short day |
Peak sun hours factor in typical cloud cover — use these for solar panel and shade-planning calculations.
Soil Temperature & Composting in Union County
Monthly soil temps tell you when to plant warm-season crops, and when your compost pile is actively working.
Quick context: Most root crops germinate well at 50-60°F. Most fruit-bearing crops want 65-75°F. Union County's monthly soil curve maps these windows to actual months.
Plant Warm Crops When
Soil reaches 60°F+
Soil warm enough from Aug through Aug.
Best Month to Compost
Jun
Microbial activity peaks when soil is warm.
Active Composting
4 months
Short season — insulate pile or use indoor vermicomposting.
View detailed monthly data
| Month | Soil 4" Deep | Soil 8" Deep | Compost Activity | Time to Finish |
|---|---|---|---|---|
| Jan | 4°F | 12°F | ❄️ Dormant | ~36 weeks |
| Feb | 4°F | 13°F | ❄️ Dormant | ~36 weeks |
| Mar | 14°F | 17°F | ❄️ Dormant | ~36 weeks |
| Apr | 28°F | 26°F | ❄️ Dormant | ~36 weeks |
| May | 42°F | 38°F | 🐢 Slow | ~24 weeks |
| Jun | 52°F | 45°F | ♻️ Active | ~14 weeks |
| Jul | 59°F | 53°F | ♻️ Active | ~14 weeks |
| Aug | 62°F | 57°F | ♻️ Active | ~14 weeks |
| Sep | 51°F | 52°F | ♻️ Active | ~14 weeks |
| Oct | 38°F | 41°F | ❄️ Dormant | ~36 weeks |
| Nov | 25°F | 31°F | ❄️ Dormant | ~36 weeks |
| Dec | 13°F | 21°F | ❄️ Dormant | ~36 weeks |
Highlighted rows = soil 60°F+ (safe for warm-season transplants). Compost finishes fastest during peak activity months.
Pest & Disease Pressure in Union County
Computed from local climate patterns — warmer, humid conditions increase pest generations and fungal disease risk.
Why it matters: Pest score isn't pass/fail. It's a planning input. Higher scores mean: more compost (resilient plants), wider spacing (air circulation), resistant varieties (built-in defense), and inspection (catch issues at egg stage).
Insect Pest Pressure
Moderate — common pests appear but manageable with monitoring.
Disease Risk
Low disease risk — dry conditions reduce fungal problems.
Seasonal Risk
View 6 common pests in your area
| Pest | Risk Level | Peak Months |
|---|---|---|
| Aphids | Moderate | May, Jun, Jul, Aug |
| Japanese beetles | Moderate | Jun, Jul, Aug |
| Squash bugs | Moderate | Jun, Jul, Aug |
| Tomato hornworms | Moderate | Jul, Aug |
| Cabbage loopers | Moderate | May, Jun, Jul, Aug |
| Slugs | Low | Apr, May, Jun |
Organic pest management tips
- Maintain healthy soil with regular compost additions to build natural pest resistance
- Practice crop rotation annually to break pest cycles
- Encourage beneficial insects with flowering herbs like dill, fennel, and yarrow
Cover Crops for Union County
Cover crops protect bare soil, fix nitrogen, suppress weeds, and improve soil structure — with planting dates calibrated for your area.
Quick context: Cover crops do four things at once: fix nitrogen (legumes), suppress weeds (any), prevent erosion, and add organic matter when chopped down. Union County's seasonal pattern determines which species fit which gap.
Spring Cover Crops (3 options) — Build soil before the main growing season
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Buckwheat | May 4 | Aug 7 | — | Rapid growth, attracts pollinators, suppresses weeds |
| Sorghum-sudan grass | May 3 | Jul 31 | — | Massive biomass, breaks compaction, suppresses nematodes |
| White clover | Apr 4 | Aug 7 | ✓ Yes | Living mulch, fixes nitrogen, permanent ground cover |
Summer Cover Crops (1 options) — Fill gaps and suppress weeds between plantings
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Sunflowers | May 28 | Sep 25 | — | Deep roots break compaction, attract pollinators and beneficial insects |
Fall Cover Crops (6 options) — Plant after harvest to protect soil over winter
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Austrian winter peas | Aug 15 | Apr 16 | ✓ Yes | Fixes nitrogen, good for heavy clay soils |
| Daikon radish | Aug 17 | Apr 16 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Jul 28 | Apr 16 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
| Oats | Aug 28 | Apr 16 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | Jul 9 | Apr 16 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Jul 13 | Apr 16 | — | Erosion control, weed suppression, good biomass |
Wind & Microclimate in Union County
The practical takeaway: Plants lose water through tiny leaf pores. Wind accelerates that loss dramatically — a 15 mph day can double a calm day's irrigation need. Union County's 9.5 mph background wind is something to design around, not against. Windbreaks made of perennial shrubs save more water than any drip system.
Wind dries soil, stresses plants, and affects frost patterns. Understanding your exposure helps with garden placement.
Seasonal Wind Speed
Spring: 13 mph Summer: 10 mph
Fall: 9 mph Winter: 13 mph
Prevailing wind: SW. Moderate wind — consider a temporary windbreak for young seedlings.
Windbreak Benefit
5.1/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
Moderate
Some terrain variation (770 ft range). Garden on slopes or higher ground if possible to avoid late-season frost pockets.
Rainwater Harvesting in Union County
How much water you can collect, when to collect it, and what size system you need for your garden.
The practical takeaway: A single rain barrel under a downspout catches 50 gallons in a 0.5" storm. Union County's 18" annual rainfall means even modest harvesting systems quickly amortize their cost in water savings.
Annual Collection
8,672 gal
Per 1,000 sq ft of roof area (at 80% collection efficiency)
Recommended Setup
8 rain barrels (55 gal each)
For a typical 500 sq ft garden. Serious collectors: consider a 2,000 gal tank.
Legal Status
Unrestricted
Rainwater harvesting is fully legal in your state with no restrictions.
Best Collection Months
Jul, Aug, Sep, Oct
Highest rainfall months — your barrels will fill up quickly during these months.
Months to Draw From Storage
Feb, Apr, May, Jun
Dry months when you'll rely on stored water — size your storage for this gap.
Rainwater collection tips for your area
- Your county receives approximately 17.4 inches of rain per year
- A 1,000 sq ft roof can collect roughly 8,672 gallons annually
- Rainwater harvesting is fully legal in your state
- In your dry climate, every drop counts — consider a larger cistern system
- Position collection tanks in shade to reduce evaporation and algae growth
Soil & Growing Conditions in Union County
Soil Type
Sandy Loam
Soil pH 6.9–8.3 · Excessively Drained drainage
Raised beds strongly recommended here — native soil drainage or texture limits in-ground options.
Watering Needs
Drought stress: 9.5/10
Very high drought stress. Irrigation is critical for garden success. Focus on water-efficient techniques and drought-adapted crops.
Season Tips
162-day frost-free season
Start warm-season crops indoors and focus on short-season varieties. Cold frames extend your season by 3–4 weeks in fall.
Your Free Printable Garden Planner
Plan every bed, every planting, every harvest — in one place. This 22-page printable includes your zone's planting calendar, a month-by-month task list, a seed inventory tracker, a harvest log, and succession-planting charts. Built to print, write in, and actually use all season.
Recommended for Your Garden
Retain moisture and nutrients in sandy soils with expanded vermiculite.
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
Get instant, accurate soil pH readings to fine-tune your amendments.
Monthly Planting Guide for Union County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Union County.
Frequently Asked Questions
What planting zone is Union County, NM?
Union County is in USDA Hardiness Zone 6b. This zone classification determines which perennial plants survive winter and sets the baseline for frost timing across the county.
When is the last frost in Union County, NM?
Based on 31 years of NOAA weather station data, the median last spring frost in Union County falls around April 30. In 8 out of 10 years, last frost lands between April 16 and May 17 — a 31-day window of variability. Use May 17 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Union County, NM?
The median first fall frost in Union County arrives around October 9. In cold years it can arrive as early as September 23; in mild years as late as October 24. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Union County?
Union County has a frost-free growing season of approximately 162 days. This is enough time for most warm-season crops including tomatoes, peppers, and squash with proper timing.
What is the soil like in Union County for gardening?
Union County has predominantly Sandy Loam soil with a pH range of 6.9–8.3 and Excessively Drained drainage. The native soil conditions make raised beds a particularly good investment here — they let you control drainage and fertility independent of the ground soil.
What is grown commercially in Union County?
Union County has commercial agriculture that includes Cattle, Cotton, Hay, Dairy. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is Union County a good location for home gardening?
Union County scores 36/100 (Challenging) on our Microclimate Index, which combines frost reliability, drought pressure, soil challenge, elevation risk, and long-term climate trend. Gardening here benefits from close attention to frost timing and season extension due to the challenging microclimate factors.
Your Union County Garden Planner — Free
A 22-page printable planner built for Union County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.
The Gardener's Encyclopedia to Companion Planting
The pairings that make vegetables, herbs, and flowers grow better — and the ones that quietly wreck a bed.
- Proven pairings for 200+ vegetables, herbs, flowers, and fruits
- Full seed-starting + planting schedule with timing and spacing
- Bonus: square-foot gardening guide + printable seasonal planners
Seed Saving & Storage Guide
Most saved seeds go bad before next season. This shows exactly when to pick, how to dry, and where to store seeds from 200 plants so yours don't.
- 200 plants, step-by-step: life cycle, pollination type, isolation
- Exact temperature + humidity ranges that keep seeds viable
- Bonus: searchable Google Sheets tracker + custom GPT assistant
Composting Guide for Homesteaders
Turn kitchen scraps and yard waste into compost that actually feeds the garden — instead of a pile that smells, attracts pests, and never breaks down.
- 14 sections on composting methods, soil science, and troubleshooting
- The 7-step hot-compost system from start to finish
- Bonus tools: troubleshooting chart, safety guide, monitoring log