Gardening Tips for September 2025 In Arizona

Here are gardening tips for September 2025, tailored to U.S. climate zones, with a focus on late-summer/early-fall transitions. Whether you’re cleaning up, planting fall crops, or preparing for winter, September is a key month in the garden.

🌿 GENERAL GARDENING TIPS FOR SEPTEMBER

✅ 1. Harvest & Clean-Up

• Harvest remaining summer crops (tomatoes, squash, cucumbers).

• Pull spent annuals and vegetables to prevent pests and disease.

• Cut back faded perennials (like lilies and hostas).

✅ 2. Soil Preparation

• Add compost or aged manure to garden beds.

• Test your soil before fall planting or cover cropping.

• Mulch bare soil to suppress weeds and retain moisture.

✅ 3. Fall Planting

• Cool-season vegetables: Start seeds or transplants of:

  • Lettuce, kale, spinach, broccoli, cabbage, beets, carrots

• Bulbs: Begin planting spring-flowering bulbs like tulips, daffodils, crocus (especially in northern zones).

• Perennials: Great time to plant or divide many perennials.

• Trees & shrubs: Plant now so roots can establish before frost.

✅ 4. Water Wisely

• Water deeply but less frequently as temperatures cool.

• Check irrigation systems and reduce watering schedule.

• In dry climates (like Arizona), continue to water container plants and trees.

📍 REGIONAL HIGHLIGHTS (U.S. Zones)

🌵 Southwest (e.g., Arizona, NM, Southern CA – Zones 9–10)

• Start fall vegetable gardens: peas, radishes, leafy greens.

• Plant desert-adapted perennials and succulents.

• Fertilize citrus trees if needed.

• Keep mulched areas cool and weed-free.

🌻 Midwest/Northeast (Zones 4–6)

• Sow cold-hardy greens and root crops.

• Begin leaf cleanup and composting.

• Protect tender plants from early frost with row covers.

• Plant garlic late this month or early October.

🌳 Pacific Northwest (Zones 7–9)

• Direct sow lettuce, spinach, and arugula.

• Harvest apples, pears, and late berries.

• Begin pruning raspberries and blackberries after fruiting.

🌴 Southeast (Zones 7–10)

• Ideal time to plant fall flowers (pansies, snapdragons).

• Start fall herbs: parsley, cilantro, dill.

• Watch for fungal diseases in humid areas.

🌼 FLOWER GARDEN TASKS

• Deadhead annuals to keep them blooming longer.

• Start chrysanthemums and asters for fall color.

• Divide irises and daylilies if crowded.

🌱 LAWN CARE

• Cool-season lawns (fescue, bluegrass): Great time to overseed, fertilize, and dethatch.

• Warm-season lawns (Bermuda, zoysia): Reduce mowing, do final fertilizing early in the month.

🐛 PEST & DISEASE WATCH

• Watch for late-summer pests: aphids, whiteflies, squash bugs.

• Remove diseased plant material and don’t compost it.

• Use neem oil or insecticidal soap as needed.