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When to Plant Chard in Maricopa County, AZ

Swiss chard is a colorful, heat-tolerant green with large crinkled leaves and vibrant stalks in red, yellow, and white. Both the leaves and stems are edible and nutritious.

Maricopa County, Arizona is in USDA Zone 9b. The average last spring frost is January 31 and the first fall frost is December 6, giving you a growing season of approximately 309 days.

At an elevation of 4,014 feet, Maricopa County receives approximately 12.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 108ยฐF, so Chard may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Chard will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Chard successfully. Mulch heavily to conserve soil moisture.

Maricopa County, AZ (Zone 9b) Year-round
309 days
Last Spring Frost January 31
309 growing days
First Fall Frost December 6

Maricopa County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (213 days to spare)
Start indoors: Dec 20 Transplant: Jan 17 🍅 Harvest: Mar 14 – May 2
Recommended (50%) ✓ Fits season (204 days to spare)
Start indoors: Jan 3 Transplant: Jan 31 🍅 Harvest: Mar 28 – May 16
Safe Start (90%) ✓ Fits season (199 days to spare)
Start indoors: Jan 30 Transplant: Feb 27 🍅 Harvest: Apr 24 – Jun 12

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 Maricopa County

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

Soil pH

Your soil pH (7.2โ€“8.5) is more alkaline than Chard prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is low (0.7%). Add 2-3 inches of compost before planting Chard.

How to Plant Chard

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Chard

7
successive plantings in your 309-day season

Sow every 5.7 weeks. Last sowing by Oct 07 to harvest before frost.

For a dedicated fall crop, sow by Oct 11.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.2″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 2,088 gal / 100 sq ft
Drought risk

Water stress score is 10/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Chard

Chard needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Chard Needs Rainfall You Supplement Action
Jan 3.5" 0.9" 2.6" ๐Ÿšฟ Regular watering
Feb 3.5" 0.8" 2.7" ๐Ÿšฟ Regular watering
Mar 3.5" 0.7" 2.8" ๐Ÿšฟ Regular watering
Apr 3.5" 0.5" 3" ๐Ÿšฟ Regular watering
May 3.5" 0.3" 3.2" ๐Ÿšฟ Regular watering
Jun 3.5" 0.4" 3.1" ๐Ÿšฟ Regular watering
Jul 3.5" 2.1" 1.4" ๐Ÿ’ง Light watering
Aug 3.5" 2.3" 1.2" ๐Ÿ’ง Light watering
Sep 3.5" 1.9" 1.6" ๐Ÿ’ง Light watering
Oct 3.5" 1.2" 2.3" ๐Ÿšฟ Regular watering
Nov 3.5" 0.6" 2.9" ๐Ÿšฟ Regular watering
Dec 3.5" 0.8" 2.7" ๐Ÿšฟ Regular watering

Water needs are for active growing months only (Janโ€“Dec in Maricopa County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Chard 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" โ€” every day above 50ยฐF 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.

Chard needs ~1,705 GDD — county provides 9,610 GDD Excellent fit

Chard Planting Timeline โ€” Maricopa County, AZ

Chard Planting Calendar

Activity When Date Range
Start Indoors January 3 Jan 3 โ€“ Jan 17
Transplant Outdoors January 31 Jan 31 โ€“ Feb 14
Direct Sow January 10 Jan 10 โ€“ Jan 31
Harvest March 28 Mar 28 โ€“ May 16
Fall Sowing October 11 Oct 11 โ€“ Oct 25

Plant 1" deep ยท 15" apart ยท Rows 24" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors Transplant Outdoors Direct Sow
February Transplant Outdoors
March Harvest
April Harvest
May Harvest
June โ€”
July โ€”
August โ€”
September โ€”
October Fall Sowing
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

0.8"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

50โ€“60 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 9b

๐Ÿ“† Growing Season

309 days in Maricopa County

Growing Tips for Chard in Maricopa County

Direct sow Chard outdoors after January 31 in Maricopa County when soil has warmed and frost danger has passed.

Sandy soil in Maricopa County dries quickly โ€” mulch Chard with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Summer highs in Maricopa County reach 108ยฐF โ€” grow Chard as a spring or fall crop. Use shade cloth if planting in summer.

General growing tips

Direct sow or transplant after last frost. Harvest outer leaves regularly to encourage continuous production. Chard tolerates both heat and light frost.

Companion Planting

Good Companions

Avoid Planting Near

  • Corn
  • Cucumbers

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Chard in Maricopa County, AZ?

Maricopa County is in Zone 9b with an average last frost of January 31. Plan your Chard planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Maricopa County, AZ?

Maricopa County, Arizona is in USDA Hardiness Zone 9b. The average last spring frost is January 31 and first fall frost is December 6.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Maricopa County gardeners in Zone 9b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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