When to Plant Broccoli in Maricopa County, AZ
What to do in May
If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.
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It's harvest week for broccoli
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
Broccoli is a nutrient-dense cool-season crop that produces large central heads followed by smaller side shoots. It is one of the most popular garden vegetables.
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 108°F, so Broccoli may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Broccoli will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Broccoli successfully. Mulch heavily to conserve soil moisture.
Maricopa County Soil Profile
Soil Type
Sandy Loam
Soil pH
7.2-8.5
Drainage
Well Drained
Plant Planting Risk Windows
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 Broccoli's growing requirements.
Soil pH
Your soil pH (7.2–8.5) is more alkaline than Broccoli prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
Sandy soil in Maricopa County warms quickly in spring but drains fast. Broccoli 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 Broccoli.
How to Plant Broccoli
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Succession Planting Broccoli
Sow every 6.9 weeks. Last sowing by Sep 07 to harvest before frost.
For a dedicated fall crop, sow by Oct 11.
Plant Water Budget
Water stress score is 10/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Broccoli
Broccoli needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Broccoli Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | 4.3" | 0.9" | 3.4" | 🚿 Regular watering |
| Feb | 4.3" | 0.8" | 3.5" | 🚿 Regular watering |
| Mar | 4.3" | 0.7" | 3.6" | 🚿 Regular watering |
| Apr | 4.3" | 0.5" | 3.8" | 🚿 Regular watering |
| May | 4.3" | 0.3" | 4" | 🚿 Regular watering |
| Jun | 4.3" | 0.4" | 3.9" | 🚿 Regular watering |
| Jul | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Aug | 4.3" | 2.3" | 2" | 💧 Light watering |
| Sep | 4.3" | 1.9" | 2.4" | 🚿 Regular watering |
| Oct | 4.3" | 1.2" | 3.1" | 🚿 Regular watering |
| Nov | 4.3" | 0.6" | 3.7" | 🚿 Regular watering |
| Dec | 4.3" | 0.8" | 3.5" | 🚿 Regular watering |
Water needs are for active growing months only (Jan–Dec in Maricopa County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Broccoli 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.
Broccoli Planting Timeline — Maricopa County, AZ
Broccoli Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 3 | Jan 3 – Jan 17 |
| Transplant Outdoors | January 31 | Jan 31 – Feb 14 |
| Direct Sow | January 10 | Jan 10 – Jan 31 |
| Harvest | April 4 | Apr 4 – May 16 |
| Fall Sowing | October 11 | Oct 11 – Oct 25 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors Transplant Outdoors Direct Sow |
| February | Transplant Outdoors |
| March | — |
| April | Harvest |
| May | Harvest |
| June | — |
| July | — |
| August | — |
| September | — |
| October | Fall Sowing |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 2-3 times/week
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 9b
📆 Growing Season
309 days in Maricopa County
Growing Tips for Broccoli in Maricopa County
Direct sow Broccoli outdoors after January 31 in Maricopa County when soil has warmed and frost danger has passed.
Sandy soil in Maricopa County dries quickly — mulch Broccoli 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 108°F — grow Broccoli as a spring or fall crop. Use shade cloth if planting in summer.
Common pests for Broccoli in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
Maricopa County receives only 12" of rain annually. Broccoli needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Start seeds indoors 6-8 weeks before last frost. Provide consistent moisture to prevent hollow stems. Harvest heads before yellow flowers appear.
Recommended Broccoli Varieties for Maricopa County
Heat-tolerant broccoli — plant as early spring or fall crop
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Isolate 1/2 mile from other brassicas. Biennial — must overwinter roots.
Broccoli in Other Locations
Frequently Asked Questions
When should I plant Broccoli in Maricopa County, AZ?
Maricopa County is in Zone 9b with an average last frost of January 31. Plan your Broccoli planting based on this frost date — 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.
Your Maricopa County Garden Planner — Free
A 24-page printable planner built for Maricopa County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.