Weeds are basically unwanted plants or plants growing out of place. Proper identification and some understanding of how and why weeds are present in a lawn are important when selecting the best management tactics. All turf weeds can be grouped into one of three life cycles: annual, biennial, or perennial.
Annual: Produces seeds during one season only
Biennial: Produces seeds during two back-to-back seasons
Perennial: Produces seeds over many seasons
Knowing the types of weed previously present in an area also can help one to be better prepared and what control measures to employ in the future.
Weeds may appear in multiple categories, either broadleaf, grass, or Sedges/rushes.
Broadleaves, or dicotyledonous plants, have two cotyledons (seed leaves) when the weed seed germinates.
Appearance: Broad, flat leaves with net-like veins and usually have showy flowers.
Common types: Clover, ground ivy, dandelions, chickweed, plantain, henbit, beggarweed.
Grasses are monocotyledonous plants that have only one cotyledon, or seed leaf, present when seedlings emerge from the soil.
Appearance: Narrow leaves with parallel veins in their true leaves. Hollow rounded stems.
Common types: crabgrass, goosegrass, crowfoot grass, bull grass, annual bluegrass, alexander grass, cogon grass, torpedo grass, and smut grass.
Sedges/rushes. Both favor a moist habitat. Appearance: triangular-shaped, solid stems, while rush stems are round and solid.
Common types: yellow and purple nutsedge and, to some degree, globe, Texas, annual, and water sedge.
One of the first steps in managing weeds is to have a healthy dense lawn/ turf to provide shade that prevents seed germination. Having a healthy lawn depends on turf species selected – making sure you put the right plant and right place. Other factors that influence a heathy turf and a reduced amount of weeds include proper cultural control, fertilizing regularly, mowing at the appropriate height, watering deeply, reducing traffic, pest control, and sanitation. If you only have a few bothersome weeds in your lawn, you may be able to dig them up by hand—but if your lawn is overrun with weeds, you may need to start from scratch. If you decide to start from the beginning, you have a choice ahead of you. Do you want to lay down seed or sod? There are pros and cons to each.
Pros: Less expensive, more variety
Cons: Takes longer to germinate, can only lay at certain times of year depending on grass type
Pros: Instant grass, can lay any time of year, requires little maintenance
Cons: More costly, less variety in grass can mean less healthy lawn overall
To prepare the soil after either method, make sure you till it down to roughly 6 to 8 inches.
Summer should be the time to relax and enjoy the fruit of all the hard work performed in the landscape over the previous winter and spring. However, there are still some essential tasks that need to be completed during the summer. Perform them in short energy bursts early in the morning or late in the evening.
1. Aerate Your Lawn
If your yard is starting to look weak and thin, even with fertilizing and proper moisture, it may need aeration. Aeration, which is creating channels into your lawn, allows water and nutrients to reach the deep roots of your grass more efficiently.
To test if you need to aerate your lawn, shovel up a patch of grass to a depth of at least four inches. If the layer of thatch is a half-inch thick or higher, your yard would benefit from aeration. There are self-drive aeration machines and tractor-pulled devices you can rent to make quick work of large areas. For smaller areas, simply punching multiple holes with a pitchfork will do the job.
Turf grass often displays a yellow color during the mid-summer rainy seasons due to the heavy rains flushing nitrogen away from plant roots. If your lawn is looking sad and yellow, chelated iron can often give a temporary green-up. Iron is not a replacement for nitrogen, but it can work well during our summer rainy season.
If you soil test revealed a potassium or magnesium deficiency, summer is a good time to make the last corrective application. Potassium (K) is an essential macronutrient. Fertilizer bags typically show the percentage of potassium in a product as the third number displayed on the front of the bag (e.g., the “8” in 16-2-8). Potassium acts as a “vitamin” for turf grass, increasing root strength, disease resistance and cold hardiness.
Magnesium (Mg), also a macronutrient, is essential for the production of chlorophyll, necessary for photosynthesis, and also plays a part in the movement of carbohydrates from leaves to other parts of the plant.
3. Don’t Mow Too Short
It’s a natural inclination to want to mow your grass as short as you can, so you have the longest time until you have to mow it again. However, giving your grass a buzz cut every time you mow can hurt your lawn over time.
While some turf grasses can be mowed relatively short, like Bermudas and some Zoysias, most grass types shouldn’t be cut shorter than two-and-one-half to four inches high. Mowing shorter than that can damage the growth point and leave it susceptible to disease and pest infestation. It can also dehydrate the grass and lead to long term damage.
5. Water Infrequently but Deeply
One common mistake made by many is watering too often and too shallow. When only given frequent shallow waterings, grass will begin to grow their roots upwards to take advantage of the small amounts of water, which makes weak and unhealthy. The grass becomes even more dependent on water and very susceptible to disease and insect attack.
Try watering only once or twice a week, but for a considerably longer time so that the water can penetrate deeper into the soil and encourage downward roots. Ideally, each irrigation zone is calibrated to determine the length of time it take to deliver ½ – ¾ inch. Then set the system to run every 3-4 days for that number of minutes. While checking the irrigation delivery system, make sure the rain shut-off device is working and set to the same ½ – ¾ inch.
6. Prevent Mosquitoes
Summer rains on a nearly daily basis lead to lots of standing water. In less than one inch of water, hundreds of mosquitoes can hatch 3 -5 days later. Not only are these blood-sucking pests annoying, but they can also transmit dangerous diseases like West Nile and Zika Virus. Even without disease, their bites are painful and irritating.
To prevent mosquitoes, make sure no standing water is allowed to remain in your yard, either in low points or in empty containers like flower pots or wheelbarrows. Any amount of stagnant water is the perfect breeding ground for mosquitoes. Take a walk around the yard, dumping out water and disturbing the oak and magnolia leaves that are acting a collection cup. Treat birdbaths and water features with floating “donuts” specifically designed to kill mosquito eggs.
While getting tasks done in quick morning trips to the yard, make sure to keep hydrated. Heat exhaustion can happen fast.
Dr. Bryan Unruh with robotic mower. Credit: UF/IFAS
With gas prices increasing, there are practical ways to reduce gasoline use in your own backyard.
There are electric, battery, solar powered and robotic (autonomous) lawnmowers. Do you remember the non-motorized reel mower? Or, you could use sheep. But, for the time being, most people have gasoline powered mowers. There are costs involved with mowing, including the cost of gas or diesel fuel.
Be smart as to where you grow grass. Use grass where it serves a purpose. Concentrate your efforts in growing grass where it will grow. It’s normal for lawns to decline in close proximity to large trees. As a lawn gives way to tree competition, do something else in that area. Use mulch under trees or plant shade tolerant plants.
Fertilize smart. Lawns need fertilizer. But, too much fertilizer, particularly too much nitrogen, results in excessive grass growth that requires more mowing.
Many homeowners overdo it with too much nitrogen and too little potassium. Fertilizers with the correct ratios of nitrogen to potassium will produce the right balance of shoot to root growth. Choose a fertilizer such as 15-0-15 or some similar analysis with some slow release nitrogen. Fertilize to produce adequate growth and the correct color. If your lawn is a healthy green and you’re mowing, mowing, mowing… why add more fertilizer?
Centipedegrass and bahiagrass will grow best with fewer problems when fertilized sparingly. This would be one or two light applications of fertilizer per year, or none at all if these grasses are performing well. St. Augustinegrass and zoysiagrass might get by on one spring application; however, it’s more common to apply a second time during summer.
Never apply more than the recommended amount of fertilizer per application. You can always split the total amount into two or more applications, which will produce more even growth and minimize sudden growth spurts.
Though it’s a popular practice, reconsider overseeding your lawn with ryegrass this fall. Weigh the desire to have a green lawn through winter with the extra time and costs (gas, fertilizer, water and pesticides) involved with maintaining it.
Finally, keep your gas-powered lawnmower in good working condition. It can make a difference in how efficiently it operates. Make sure the equipment is clean. Change the oil if needed. Replace or clean the air filter and spark plug. Keep lawnmower blades sharp. Basically, follow the owner’s manual for routine maintenance.
Implementing these ideas can help conserve fuel and result in a healthier lawn.
The lawn is a staple when you picture the typical American home. It is where your kids play, where you stand to associate with your neighbors and the first impression you give to passers-by. It has also no doubt been a subject of frustration as you notice brown patches or open spots. Could this situation have been avoided in the first place? Lawn care is a topic we address in extension extensively. Proper maintenance practices will help your lawn be green and healthy providing you with years of enjoyment. Below are a few principles that if applied will help you avoid issues and grow a worry-free yard.
Before you do anything else you will need to know what species you are working with. In this area we have warm season grasses with names like centipede and zoysia. Their individual characteristics will identify yours from the others. For instance, centipede grass is a lighter color with a course textured blade about 1/16 to 1/8 inches wide and a creeping habit as it spreads via stolon. This is very basic, as identifying grasses could be a day long course on its own. Knowing your lawn species will inform you as to mowing height and when periodic tasks such as dethatching may be necessary. All of these are necessities for a healthy lawn, but there are two universal tasks that need to be on the forefront of your mind.
Irrigation is arguably the most important topic in lawn care. Improper watering may cause your grass to die back opening bare spots for weeds and insects to infiltrate. Scheduled irrigation is not the best option. Your grass will tell you when it needs water. Look for indicators such as folding blades, color change, and lingering footprints as keys to irrigation. When you see these, apply ½ to ¾ inch of water preferably in the early morning. Take your soil type into consideration when watering as you will want this water in the root zone. Sandy soils may need a little more to saturate the area while clay may need to soak in through multiple applications. Watering only when required will encourage deeper rooting of your grass. So, how do you know how long to run your system? Calibrate your system by placing straight sided cans in your watering zones. Run the system until they fill to the desired level. The amount of time this takes will tell you how long you should run the system. While you are calibrating the system, take a look at where the sprinkler heads are aimed. Readjust any that place water in undesired locations like the street. Lastly, install a rain sensor. The Panhandle received an average 68.32 inches of rain in 2021*. There is no need to run your water system if mother nature is doing it for you.
Fertilization is another often misunderstood topic. Grass is a plant, and therefore requires nutrients to thrive. Over doing it in certain grasses may cause them to die back much like improper irrigation. Application rates vary by grass species and are given in terms of required nitrogen per 1000ft2 for a single growing season. You can tell how much Nitrogen a fertilizer has by looking at the first of the three-digit NPK rating. It indicates the amount by weight in the bag (8-8-8 = 0.08lbs nitrogen per 1lb fertilizer). Keep in mind that rate of fertilizer your grass needs is for the entire year. This means you will want to apply multiple times. So, if you need 13lbs of fertilizer it is best to apply about 4.33lbs three times across the growing season versus all at once. Only apply fertilizer during active growth. In the Panhandle this is mid-April through mid-September. Appropriate rates and timing will keep those expensive fertilizers in your root zone and not in our local waterways.
Appropriate care will provide lush healthy growth and a full lawn. Taking the time to identify your grasses will inform you as to what it needs to support your family for years to come. Appropriate irrigation and fertilization will in-turn support the health of local watersheds and potentially save you some money and effort. For more information on lawn maintenance, see these Ask IFAS documents, or contact your local extension agent for additional information on this and any topic regarding your gardens and more.
Chewing caterpillar damage on St. Augustinegrass Photo by: Steven Arthurs, UF
Tropical sod webworm larvae are destructive pests of warm season turfgrasses in the southeastern U.S. especially in the fall. Commonly referred to as a worm, they are truly caterpillars, the larvae of a moth. Larval feeding damage reduces turfgrass aesthetics, vigor, photosynthesis and density, which is very evident on finer-bladed grasses such as bermudagrass and zoysiagrass. Feeding damage is possible on all grass types however. Adults, a dull brown colored moth about ¾ inch long, rest in sheltered and shrubby areas during the day and are active at dusk. Females deposit clusters of 10-35 eggs on the upper surface of grass blades. The eggs hatch in 3-4 days and develop from a 1 mm long caterpillar to one over 11 mm long through six instars within 21 to 47 days, depending on temperature. Larval feeding occurs at night, leaving the grass looking ragged, shortened and missing.
Sod webworm on soil surface Photo by: Steven Arthurs, UF
Control should be against damaging larvae, not the flying moths. However, insecticidal soap applications to moth harboring areas can reduce re-population frequency. Soil-drenching soap flushes can be used to find the caterpillars, especially in dry and hot grass areas. Bacterial-based insecticides, such as Bt, Bacillus thuringiensis var. kurstaki or Spinosad, will control sod webworm caterpillars without impacting beneficial species as long as they are applied with each flush of grass growth.
Fall armyworms are also active when the weather turns cooler. They feed any time of the day or night, but are most active early in the morning or late in the evening. The 1 ½ inch long gray and white moth lays about 1,000 eggs in multiple masses on any vegetation. Two to 10 days later, the small caterpillar hatches and begins to grow to nearly 2 inches long over a two week period. The fall armyworm is easily recognized by its dark head marked with a distinct pale-colored inverted Y and the long black stripe running along each side of its body. These aggressive feeders “march” rapidly across grassed areas consuming every above-ground plant part. While bacterial-based insecticides will reduce the numbers, control of armyworms usually requires synthetic insecticides.
Armyworm Photo by: Jim Castner, UF
The good news is that grass “worms” can be controlled and the blades will grow back. The damage may be devastating to see, but usually not a permanent problem.
As October gets by us and November quickly approaches, I would like to include the preparation on What to Plant? And What to Do? Some great annual plant choices are digitalis (foxglove), petunias, and Shasta daisy. There are many daffodil bulb varieties for North Florida including the following: Carlton, Fortune, Silver Charms, Thalia, and Sweetness. We will be getting into more of the cooler days, so this is a good time to start bulb onions and salad crops such as arugula, lettuce, and spinach. Dill, fennel, oregano, and sage are all herbs that can be planted throughout the fall months.
Start preparing now so your fall garden will be full of dark leafy greens, multi-colored lettuces, and root vegetables of all shapes and sizes. Photo by Molly Jameson.
In lawns there are a few key things that can be done in October. It is possible to control winter weeds before they appear. This is the time to use preemergent herbicides when nighttime temperatures are between 55-60 degrees Fahrenheit for four to five days in a row. If a green lawn is desired, you can overseed with annual ryegrass when the daytime temperatures are in the low 70s. Remember, the lawn will still need to be watered and mowed to maintain a healthy ryegrass. Watch for fungus like brown patch and large patch disease. This can become active when the soil temperature is between 65-75 degrees Fahrenheit.
Hollies also attract bees to the landscape. Credit: Beth Bolles, UF IFAS Extension Escambia County
And last but not least as you prepare for winter around the corner you can plant evergreen hollies that will make it through the cold and provide a splash of color with red berries. Gather pine needles that are dropping and use as a natural mulch, and this is the last month that strawberry plants can be established in a bed or a large container.