September Gardening Checklist for Central Texas


September is a gardening transition time in central Texas. At some point during the month, the weather changes. Maybe it is a bit cooler one morning or evening, but the weather begins to noticeably shift. It could be rain after an extended drought but whatever occurs, that is when a gardener knows that fall gardening is about to commence. 

September is a good time to add new growing areas to vegetable gardens and landscapes. If there is a problem area in your landscape, spend some time coming up with a plan to make changes and improvements. Determine what materials will be needed for “do it yourself” projects or identify a someone to do the project.

Days can still be warm in September, so plan to do outside chores early or late in the day. Cooler weather is coming, so get ready and get gardening with these checklist tasks.  

What to plant in Central Texas in September?  

Planting season kicks off in September in Central Texas and continues usually into November. As weather gets cooler and especially after a rain, begin to replace plants and add new plantings. Evaluate your garden and take inventory of the plants that performed best through the summer. Source those plants – shrubs and perennials – to be ready for planting. Fall blooming perennials to look for are autumn aster, butterfly ginger, garden mums and Mexican mint marigold.  

Fall is prime time for butterfly gardens in central Texas. To entice these winged beauties to your garden be sure to include perennials such as Gregg’s mistflower and Mexican bush sage. See my July gardening checklist for more of the plants that not only survive but thrive in Texas heat.

If you would like to add a tree, begin looking into possibilities and locating sources. Be sure to see my October checklist for detailed information on tree selection and planting. The first Friday of November is Texas Arbor Day.

Divide and transplant spring blooming perennials like daylilies, iris, daisies and cannas. Liriope and ajuga, if growing vigorously can be divided and transplanted. Be sure to replenish mulch as you add new plants.

Depending on the weather, some cool season and transitional annual flowers can be planted late in the month. Refresh containers and begin filling them with fall ornamentals as they become available. Look for celosia, copper plant, dianthus, dusty miller, gazania, marigolds, petunia and snapdragons. 

If you do indoor seed starting, quickly plant seeds of calendula, feverfew, poppies, rudbeckia, scabiosa, snapdragons and stock. These may be started indoors in August through the first week or so of September for zone 8b.   

Order seeds of fall planted annuals for spring flowers – bluebonnet, larkspur and poppies. Order bulbs that are planted in fall for spring blooms – daffodils, tulips and hyacinths.

Spread compost in borders and beds to alleviate the effects of summer’s heat and drought. Extreme hot, dry summer weather impacts beneficial soil microbes. Reinvigorate your soil by applying a finished compost.  

Turfgrass can be planted but do this very early in the month so that it has time to develop enough roots to carry it through the winter before going dormant. 

What to do in the Vegetable Garden in September 

September through February is considered by many, myself included to be one of the best vegetable gardening seasons. Weather is mild, pests are few, vegetables thrive in cooler weather and it is more comfortable to be outdoors in central Texas. If you’ve been wanting to start home gardening, this is the best season to start.  

Prepare vegetable gardens for the cool growing season. Clean the garden, remove weeds and debris from planting areas. Add compost or shredded leaves to enrich the soil. Get these seeds for fall planting – beets, carrots, chard, lettuce, mustard greens, snow and snap peas, radish and turnips.    

While all these vegetables may be planted in September, note that the prime planting time for all these crops, starts midway through the month in central Texas. The exception is artichoke with the entire month of September as prime planting time. Adjust planting times for your zone.

What are good things to plant In September?

Here are planting periods for vegetables by seed and *transplant for zone 8b central Texas:

Week 1 – *artichoke, bush bean, pole beans, beets, radish, Swiss chard, turnips

Week 2 – *artichoke, bush bean, beets, bok choi, *broccoli, *Brussels sprouts, *cabbage, *cauliflower, *collards, garlic, *kale, *kohlrabi, leeks, mustard, *onion/green bunching, radish, Swiss chard, turnips

Week 3 – *artichoke, beets, bok choi, *broccoli, *Brussels sprouts, *cabbage, carrots, *cauliflower, *collards, garlic, *kale, *kohlrabi, leeks, mustard, *onion/green bunching, peas – English/snow/snap, radish, Swiss chard, turnips

Week 4 – *artichoke, beets, bok choi, *broccoli, *Brussels sprouts, *cabbage, carrots, *cauliflower, *collards, garlic, *kale, *kohlrabi, leeks, mustard, *onion/green bunching, peas – English/snow/snap, radish, turnips

Pruning and mowing in September

Clean out spent summer annuals and remove damage off perennials. Some spring to summer blooming perennials like sage or cape plumbago benefit from pruning a couple of times during the growing season. Fertilize to invigorate them and promote fall flowering.

Prune roses from a fourth up to one third, if you have not already done so. Then fertilize with a high nitrogen product and mulch well for repeat bloomers. These are “lifetime” hand pruners, my favorite.

Prune dead limbs and branches from trees that could be broken off in wind during winter.  

Lawn care in September

Mow lawns regularly, removing no more than one third of the leaf blade at each mowing. If watered, lawns still grow in September but with cooler nights growth will slow down. 

Continue to water if needed but irrigate early in the morning to avoid development of fungal diseases. If possible, set automatic irrigation systems to run between 4am to 9am. Use timers made for hose end sprinkler applications. The goal is to get soil moist down to 3 to 4 inches.

Watering lawns and landscapes 3 to 4 times a week results in wasteful runoff, grows shallow rooted turf, may promote disease and can literally drown some plants.

What to fertilize in September

Fertilize garden roses after pruning with nitrogen. Also, containers and hanging baskets with water soluble nitrogen every 2 weeks.  

Should you fertilize your lawn in September? September is a good time to fertilize lawns in Central Texas if needed. Some turf experts say this is the most important time to fertilize. It “winterizes” lawns and  promotes healthier turf for the spring. This is best done based on a soil test performed every 3 to 5 years. 

Landscape pests in September 

If hot weather persists into the month, continue to be on the lookout for insect pests. Watch for aphids, lace bug and red spider mites on ornamentals and chinch bugs in lawns. See my August checklist for information on recognizing and managing these pests. 

September is fire ant awareness month because it is one of the best times to apply a broadcast bait to control this pest. This is an economical and environmentally friendly control method.  

Watch for brown patch (aka large patch) in St. Augustine lawns. Cooler nights and high humidity encourage development of this fungal disease that shows up as roundish patterns of browned turf. A fall application of fungicide is a good management strategy.   

Apply pre-emergent herbicides this month when the soil temperature is at 70 degrees for about a week. This prevents certain winter annual weeds like henbit, rescue grass and bluegrass.

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