August 28, 2025 – With August almost gone, it’s time to look at gardening in September. September can be a difficult month, as hot summer temperatures can hang on throughout the month, while in some years the cool fall temps arrive quickly, and fall begins. To prepare for the much-awaited cool season, gardeners have several things to do to make the season change a beautiful and productive time for your landscape.
CLEAN UP IN THE GARDEN
Begin your fall clean-up by removing all spent summer flowering plants and veggies, including any weeds that are present. Put all plant refuse in either the compost pile or the trash. Dead plants can harbor insects and/or disease, so it is important to remove them completely from the garden areas and any containers that will be re-used.
ADD COMPOST
2-4 inches of compost, tilled or mixed into the soil, will give your fall plants a healthy start, and also improve the soil. Compost helps the soil to retain moisture, reduce clumping, and adds nutrients. Container potting mix will also benefit from a dose of compost as well.
MULCH
A layer of mulch 2”-4” deep around your new plantings will keep the soil moist and give some protection when the temperatures drop at night. Mulch also helps keep weeds from germinating, and as it decays, improves the soil.
PRE-EMERGENT TREATMENT
Early September is prime time for applying a pre-emergent to both lawn and garden areas. Pre-emergents have a short window for application, and are not effective when applied after the weeds have germinated. Apply according to recommended rates and water-in thoroughly for best results.
Dimension, Balan, and Halts are 3 pre-emergent products that can prevent winter weeds.
LAWNS
Keep lawn grasses at recommended heights—1 ½” for Bermuda, and 2 ½” for St. Augustine. Try to mow regularly so that the mower doesn’t remove more than 1/3 of the grass leaves. If we have a “wet” fall with lots of rain, watering can be reduced to ½” per week. A fertilizer with a 3-1-2 ratio (15-5-10 or similar) can be applied for a final feeding in September.
VEGETABLES
Broccoli, cauliflower, cabbage, collards, Brussel sprouts, beets, radishes, and turnips can all be planted in early September, with plenty of time for harvest before the first frost. At planting, water thoroughly, and aim to keep the soil moist by using mulch. Fertilize every 2 weeks for higher yields.
FLOWERS
Check local garden centers for fall flowering plants. Many plants have vibrant colors in the fall, and the selection is large. Don’t forget that fall is the best time to plant trees and crape myrtles!
