September Gardening in Alabama: A Second Spring in the Deep South

September 2025 - As summer's grip begins to loosen and the air takes on a gentler edge, Alabama gardeners find themselves at a seasonal crossroads. September isn't just a transitional month-it's a second spring. With soil still warm, rainfall more frequent, and daylight hours gently waning, this is one of the most productive and rewarding times to dig in.

Whether you're tending raised beds in the foothills of North Alabama, refreshing ornamental borders in Birmingham, or coaxing greens from sandy soil along the Gulf Coast, September offers a bounty of opportunity. Here's how to make the most of it.

Know Your Zone: Timing Is Everything

Alabama spans USDA Hardiness Zones 7b to 9a, meaning frost dates and planting windows vary across the state:

• North Alabama (Zone 7b–8a): First frost typically arrives late October to early November. September is prime time to transplant brassicas and sow root crops.

• Central Alabama (Zone 8a): Frost comes mid to late November. You have a wider window for staggered planting.

• South & Coastal Alabama (Zone 8b–9a): Frost may not arrive until late December-or not at all. You can double-dip with warm-season crops early in the month and cool-season staples later.

Understanding your zone helps you time plantings for optimal growth and harvest.

What to Plant: Cool-Season Crops Take Center Stage

September is ideal for planting cool-season vegetables that thrive in Alabama's fall climate. These crops root quickly in warm soil and mature as temperatures drop.

Direct Sow:

• Carrots

• Beets

• Radishes

• Turnips

• Spinach

• Mustard greens

• Swiss chard

• Lettuce

• Collards

• Kale

Transplants:

• Broccoli

• Cabbage

• Cauliflower

• Brussels sprouts

• Onion sets

In South Alabama, you can even sneak in a final round of bush beans or summer squash in early September before cooler nights settle in.

Divide and Conquer: Perennials and Ornamentals

September is the perfect time to divide overcrowded perennials like daylilies, irises, hostas, and coneflowers. The soil is still warm enough to encourage root establishment, and cooler air reduces transplant stress.

• Dig up mature clumps and gently separate them.

• Replant divisions with compost and water deeply.

• Mulch to retain moisture and suppress weeds.

This rejuvenation sets the stage for stronger blooms next spring.

Mulch, Compost, and Soil Prep

After a long summer, your soil may be tired. September is the time to refresh mulch layers, build compost, and rejuvenate garden beds.

• Add 2–3 inches of pine straw or bark mulch around trees and shrubs to insulate roots and retain moisture.

• Start a compost bin with falling leaves, kitchen scraps, and spent summer plants.

• Mix in organic matter like compost or aged manure to improve soil structure and fertility.

Use a digging fork or broadfork to aerate without disturbing soil layers. Healthy soil means healthier plants.

Cover Crops: Feed the Soil, Not Just Yourself

Empty garden beds don't have to sit idle. Planting cover crops like crimson clover, winter rye, or Austrian winter peas helps prevent erosion, suppress weeds, and enrich soil with organic matter.

• Sow seeds in cleared beds.

• Water lightly until established.

• Let them grow through winter, then till under in spring.

Cover crops are a low-effort, high-reward strategy for long-term soil health.

Seed Saving and Herb Cuttings

September is a great time to collect seeds from summer favorites like zinnias, marigolds, and sunflowers. Once flower heads dry, snip them off and store seeds in labeled envelopes in a cool, dry place.

For herbs like basil, oregano, and thyme, take cuttings before the first frost:

• Snip 4–6 inch stems.

• Remove lower leaves.

• Place in water or moist soil.

• Keep in bright, indirect light until roots form.

These cuttings can be overwintered indoors or replanted in spring.

Pest and Disease Management

As temperatures cool, some pests retreat-but others surge. Keep an eye out for:

• Aphids on fall roses and brassicas

• Thrips on camellias and gardenias

• Fire ants in lawns (apply bait if temps stay below 80°F)

Use neem oil or insecticidal soap as needed, and avoid spraying during freezing conditions.

Landscape and Lawn Care

September is a strategic month for lawn renovation and landscape planning:

• Reseed tall fescue lawns and fertilize with slow-release nitrogen.

• Apply pre-emergent herbicides if winter weeds were a problem last year.

• Study your landscape for gaps or damaged shrubs-replace as needed.

• Spray fungicide on shrubs after fall growth to prevent disease.

This is also a good time to plant spring-flowering bulbs in North Alabama. In the south, wait until October.

Indoor Prep and Miscellaneous Tasks

Before bringing houseplants indoors, inspect for pests and diseases. Treat as needed to avoid infestations. Clean tools, sharpen blades, and organize your shed-winter will be here before you know it.

Final Thoughts: Lean Into the Season

September in Alabama is a gardener's gift-a month of renewal, productivity, and promise. While other regions wind down, we lean in. With smart timing, steady effort, and a little Southern grit, your garden can thrive from now through Thanksgiving and beyond.

Whether you're sowing spinach in Shelby County, dividing irises in Huntsville, or mulching azaleas in Mobile, this is your moment. Grab your gloves, sharpen your pruners, and let the soil remind you: every ending is just another beginning.