What to Plant in Phoenix in January

Why January Is Critical in Phoenix

Most of the country is buried in snow in January. Phoenix gardeners are starting tomatoes. Our warm-season spring crops (tomatoes, peppers, eggplant) go in the ground from mid-February to mid-March (the University of Arizona Cooperative Extension window), so January is when you start seeds and line up transplants.

Tomatoes transplanted in mid-February have about three months before temperatures hit 95°F in late May and blossom drop stops production. That's why your transplants need to be ready the moment the window opens.

What to Plant in Phoenix in January: Warm-Season Crops

Warm-Season Seeds to Start Indoors Now:

• Tomatoes — Start seeds indoors by mid-January (6–8 weeks before transplant), or line up nursery transplants for February 15–March 15. Full guide: How to Grow Tomatoes in Phoenix
• Peppers (all types) — Jalapeños, Anaheims, bells, serranos. Start seeds indoors now (8–10 weeks before the February 15–March 15 transplant window). Full guide: Peppers in Phoenix
• Eggplant — Start seeds indoors now for March 1–15 transplanting. One of the best Phoenix crops. Full guide: Eggplant in the Phoenix Desert

From Seed in January:

• Onions (sets) — Plant onion sets directly in the ground by February 1. Harvest in late spring.
• Basil — Not yet: sow from February 15 or transplant from March 1. Basil thrives alongside tomatoes in spring.
• Herbs — Oregano, chives, parsley transplants all go in January.
• Potatoes — Plant certified seed potatoes mid-January to mid-February. See growing potatoes in Phoenix.
• Asparagus crowns — Plant by February 1 (UA Extension window). See growing asparagus in Phoenix.
• Artichoke transplants — From January 15 through March 15. See growing artichokes in Phoenix.

What's Still Producing From Fall Planting in January

If you planted a fall garden in October, January is peak harvest season for cool-season crops:

• Lettuce, kale, spinach, chard — cut-and-come-again harvesting at its best
• Broccoli and cauliflower — heads forming or ready to harvest
• Carrots and beets — ready for harvest if planted in October
• Snap peas — at peak production in January

What NOT to Plant in Phoenix in January

• Tomatoes, peppers, eggplant (outdoors) — Wait for February 15 (eggplant March 1).
• Cucumbers, squash, melons, beans — Wait until February 15 (beans March 15) when soil is warmer. Planted in January these will stall and struggle.
• Okra, Armenian cucumber — Sow from February 15 once soil warms (okra by April 15).

January Frost Risk in Phoenix

Central Phoenix (Sky Harbor) freezes less than once a year on average, but East Valley areas like Mesa and Chandler average about 10 freezing nights a year, mostly in December and January. See Phoenix frost dates for your area. When frost is forecast:

• Cover transplants with frost cloth, old sheets, or cardboard overnight
• Remove coverings in the morning once temperatures rise above 40°F
• Don't panic — brief light frost rarely kills established transplants
• Seedlings under 4 inches tall are more vulnerable than established plants

Your January Garden Checklist

• ☐ Check local nurseries for tomato, pepper, and eggplant transplants (usually arrive in early January)
• ☐ Prepare raised bed soil — add fresh compost if needed
• ☐ Test soil moisture before planting (soil should be moist but not waterlogged)
• ☐ Install drip irrigation before planting if you haven't already
• ☐ Start tomato, pepper, and eggplant seeds indoors (tomatoes by mid-January)
• ☐ Plant onion sets directly in soil (by February 1)
• ☐ Harvest remaining fall cool-season crops before they bolt in February

Frequently Asked Questions

What can I plant in Phoenix in January?

In January you can plant onion sets (by February 1) and cool-season herbs, and start tomato, pepper, and eggplant seeds indoors. Tomato and pepper transplants go outside February 15–March 15 and eggplant March 1–15 (University of Arizona Cooperative Extension dates), so January is when the spring garden gets started.

Is it safe to plant tomatoes in January in Phoenix?

It's too early. The University of Arizona Cooperative Extension window for tomato transplants in Maricopa County is February 15–March 15, after the coldest nights have passed. Central Phoenix rarely freezes, but East Valley areas like Mesa and Chandler average about 10 freezing nights a year, mostly in December and January. Use January to start seeds indoors or line up nursery transplants.

What should I NOT plant in January in Phoenix?

Avoid planting tomatoes, peppers, eggplant, cucumbers, squash, melons, okra, and beans outdoors in January. Tomatoes, peppers, cucumbers, squash, melons, and okra start February 15; eggplant March 1; beans March 15.

Why is January so important for Phoenix gardeners?

January is seed-starting month for warm-season crops. Seeds started indoors now are ready for the February 15–March 15 transplant window, which gives tomatoes and peppers enough time to produce before Phoenix temperatures exceed 95°F in late May — when fruit set stops entirely.

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