What to Plant in Phoenix in March

Still Possible to Plant in March

Tomatoes, Peppers, and Eggplant (By March 15)

The University of Arizona Cooperative Extension window for tomato and pepper transplants runs February 15–March 15, and eggplant transplants go in March 1–15. Get them in early in the month if you can — every week counts before the heat.

Cucumbers and Summer Squash

If you missed February, direct sow summer squash by April 1 and cucumbers by April 15 (UA dates). You'll get a harvest, though shorter than February-planted crops. The earlier you sow, the longer you pick before the heat.

Green Beans (From March 15)

Direct sow green bean seeds from March 15 through April 15 (UA dates). Beans sown in mid-March will produce in May and are reliable right up to the heat. Sow early in the window — late plantings may struggle as temperatures approach 95°F.

Basil (March Through April)

Basil loves Phoenix spring and summer heat. Transplants or seeds go in anytime March through April. One of the few crops with a long productive window here — basil thrives until monsoon humidity promotes fungal disease in August.

Okra (By April 15)

Sow okra seeds now through April 15 (the UA window opens February 15) — it needs warm soil (70°F+) to germinate well and actually performs better when it has to struggle a bit in spring heat. Okra produces all summer in Phoenix when most other crops are resting. One of the true desert-adapted vegetables.

March Garden Tasks

Fertilize

Tomatoes and peppers transplanted in February need their first fertilizer boost. Use a balanced fertilizer (8-8-8 or similar) about 3–4 weeks after transplanting. Once you see flower buds forming, switch to a lower-nitrogen, higher-phosphorus formula to promote fruit set rather than leaf growth.

Increase Watering

March temperatures are rising — adjust your drip timer from twice-weekly to three times weekly. Tomatoes especially need consistent moisture from first flower through harvest to prevent blossom end rot and fruit cracking.

Harvest Remaining Cool-Season Crops

Lettuce, spinach, and arugula will bolt (send up a seed stalk and go bitter) as temperatures hit 75–80°F consistently. Don't wait — harvest aggressively in March before the flavor turns. Kale and Swiss chard are more heat-tolerant and can be harvested into April.

Install Cages and Trellises

If you haven't already, install tomato cages and cucumber trellises in March before plants get too large. Doing this while plants are small avoids root disturbance later.

What NOT to Plant in March in Phoenix

• Tomatoes and peppers after March 15 — Past the UA window. Won't have enough production time before summer heat.
• Eggplant after March 15 — Past the UA window (March 1–15).
• Cool-season crops — Lettuce, kale, broccoli, peas are all done for spring. Next window is October.

Frequently Asked Questions

What can I plant in Phoenix in March?

Tomato and pepper transplants (through March 15), eggplant transplants (March 1–15), green beans (from March 15), cucumbers and summer squash, basil, and okra (University of Arizona Cooperative Extension dates). After mid-March the focus shifts to maintenance and harvest.

Can I still plant tomatoes in March in Phoenix?

Yes, through March 15 — the end of the University of Arizona Cooperative Extension window (February 15–March 15). Plant as early as you can; after March 15, plants won't have enough time before Phoenix heat exceeds 95°F in late May and shuts down fruit set.

When do Phoenix spring crops start producing?

Tomatoes transplanted in late February typically begin producing in April. Cucumbers and squash planted in late February produce in April–May. Beans sown in mid-March produce in May. March is when you see first flowers and early harvests begin.

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