Starting a Bahiagrass Lawn

By Jane Morse, University of Florida/IFAS Pinellas County Extension Agent

Some of the advantages of a bahiagrass lawn are drought tolerance, low fertility requirements, relatively few disease problems and only one primary insect problem (mole crickets). Disadvantages include tall seedheads that some people find unsightly, not much tolerance to shade, traffic or saltwater, and lower performance in alkaline soils.

There are four varieties of bahiagrass available for home lawns. These varieties are Common, Argentine, Pensacola and Paraquay. All of these may be established by seed or sod. Only two of these four varieties are best suited for lawns. Argentine is relatively dense with a dark green color. It has good insect and disease resistance and tolerates cold temperatures well. Pensacola has excellent drought tolerance and tolerates either hot or cold temperatures well, but it produces an abundance of seed heads.

The best time to establish bahiagrass is during the spring or early summer months. This timing allows the grass to become established before the cooler months arrive and growth is reduced.

Properly preparing the soil before planting is critical. This should be done whether you are planting a new lawn or replanting an old one, and whether you are seeding or sodding. The first step is to remove any debris, brush, large roots, rocks, weeds or old tree stumps. Rough grade the site so it is sloped at 1 to 2 % away from the house (1/2 to 1 foot fall per 50 feet). Poorly drained soil may require installation of drainage lines. If an area cannot be leveled, use ground cover plants other than turf grass. Control of perennial weeds such as Bermuda grass and torpedo grass needs to be done during site preparation. Several applications of a non selective herbicide are usually required to get rid of these tenacious weeds.

It’s always a good idea to have a soil analysis done whenever planting is undertaken. This will provide you with information about the soil including its pH (acidity or alkalinity). Depending on which soil analysis is done, it can also provide information about the fertility of the soil and pH adjustments that may be required. To obtain a soil sample, collect several small plugs from the top 6 inches of the soil in the area to be planted. Throw all the samples together, mix them up, then take at least a cup’s worth to be analyzed. Analysis can be provided by Pinellas County Extension. (For detailed information on collecting a soil sample: http://plantingpinellas.blogspot.com/2008/04/collecting-soil-sample-for-ph-testing.html) Extension can also provide the mailing materials for a more in depth analysis done by the University of Florida

Next, install irrigation equipment if desired. Add any desired soil amendments. Just make sure that all organic soil amendment materials are sterilized to prevent the introduction of weed seeds. Rototill to loosen compacted soil and improve the speed and depth of rooting. If soil amendments, lime or fertilizer have been added, till the soil deeply down to about 6 or 8 inches.

Finally, do a final grading just prior to planting to provide a smooth planting bed. The site can be hand-raked and dragged with a hand-pulled drag. Large areas can be smoothed by tractor-drawn equipment with a tiller rake or grading box and then hand-finished. Irrigation can be used to settle the soil before planting. Hand-rake to break up a crusty surface prior to seeding.

Seeding or sodding are the next step and these will be covered in my next article. Can’t wait. . . see this publication: http://edis.ifas.ufl.edu/lh013 or Google “Establishing Your Florida Lawn IFAS.”

Information for this article came from University of Florida IFAS publications:

Bahiagrass for Florida Lawns: http://edis.ifas.ufl.edu/LH006

Preparing to Plant a Florida Lawn: http://edis.ifas.ufl.edu/LH012

Controlling Crabgrass

By Jane Morse, University of Florida/IFAS Extension Agent, Pinellas County

If crabgrass has taken over your lawn, early February is the time to put out a pre-emergent herbicide. Pendimethalin (sold as Pendulum, Pre-M, Turf Weedgrass Control, Halts Crabgrass Preventer) provides excellent control of crabgrass and is safe at the recommended rate on mature, actively growing grass (Bahia, Bermuda, St. Augustine and Zoysia). Apply herbicide when daytime temperatures reach 65 to 70 degrees Fahrenheit for 4-5 days in a row, or usually about the same time that azalea plants start blooming in the spring. Plan to reapply herbicide about 2 months later for season-long control.

If weeds are a recurring problem in your lawn, follow these steps to have a healthy, thick lawn that will out-compete most weeds:

1. Start off with the right grass. Bahia is best suited for sandy, acidic soils that are subject to drought. St. Augustine is better suited for mildly acidic to alkaline soils that are subjected to salty conditions. Also choose grasses based on the amount of care that you are willing to provide. Bahia has a low maintenance level, St. Augustine a moderate level, while Zoysia and Bermuda have a high maintenance level. For areas of dense shade choose a shade-tolerant ground cover or use mulch.

2. Mow at the right height. Set those mower height adjustments high for St. Augustine and Bahia grass which should be mowed at a height of 3 to 4 inches. Dwarf St. Augustine grasses (Delmar, Jade, Seville) are mowed at 2 - 2 ½ inches. Bermuda is mowed at ½ to 1 ½ inches and Zoysia 1 - 2 inches. Proper mowing height and frequency will get rid of many annual weeds.

3. Mow often. Only 1/3 of the leaf blade should be removed each time the lawn is mowed. The shorter it’s mowed, the more often it needs to be mowed. Repeatedly removing too much of the grass blade (more than 1/3) will eventually kill the grass. Keep the mower blades sharp for the best cut. Mow when grass is dry.

4. Water only when it needs it. When 30% of the lawn starts to show symptoms of wilt (i.e. folded leaf blades, bluish-gray color, foot-prints that last for more than 10-15 minutes, and soil is dry), water the grass (unless rain is expected in the next day). Apply ½ to ¾ inch of water each time the lawn is watered. Overly wet lawns promote sedges, spurges and dollar weed, as well as root rots. When watered and mowed correctly the grass will develop a deep root system and will not require water as often. Water in the early morning when dew is still present. Watering late in the evening promotes disease development.

5. Fertilize correctly. Lawns that have been over-fertilized are much more prone to getting chinch bugs, brown patch, grey leaf spot, pythium blight, powdery mildew and thatch. Under-fertilized lawns are prone to getting take-all root rot, dollar spot and rust. Of course, if the lawn gets attacked by these insects and diseases, large areas die off, leaving a perfect place for weeds to sprout.

Fertilize St. Augustine two weeks after the start of spring regrowth using a complete fertilizer (16-4-8) containing slow-release nitrogen (e.g., Isobutylidene diurea [IBDU], Sulfur-coated urea [SCU], urea formaldehyde, cottonseed meal, or poly-coated sources). Sewage sludge products are also a slow-release nitrogen source, but avoid them if you have palms. Apply 1 pound of nitrogen to 1000 square feet of lawn (divide 100 by the first number on the fertilizer bag to get the pounds of fertilizer to apply per1000 sq. ft.) e.g. 6.25 pounds of 16-4-8 fertilizer per 1000 square feet. Apply ferrous sulfate or a chelated iron source in July. For Bahia grass apply a complete fertilizer with slow-release nitrogen in March and August and an iron source in May.

6. Scout. Watch turf closely for symptoms of disease or insect attack. Keep track of any problems on a calendar and note the location where symptoms first appeared. Knowing when to expect a certain disease or insect pest (i.e., chinch bugs, brown patch, etc.) will help to catch problems early before much damage can be done. Pest problems should be greatly lessened or non-existent when proper maintenance steps are used. Using these steps will lessen the need for pesticides, fungicides and herbicides and help to keep our environment clean.

For more information call the Extension Service’s Horticulture Help Line at 727-582-2110, visit our website at: pinellascountyextension.org; or visit the University of Florida Turfgrass website at turf.ifas.ufl.edu.