With our warm weather, many homeowners are looking to create a beautiful lawn for the year. There are so many products in the home improvement stores and nurseries that promise to make your lawn into a green paradise. What to choose?
Photo UF/IFAS Extension. Spring is a good time to check the water flow and direction of a pop-up irrigation system and make adjustments as necessary.
UF/IFAS Extension provides advice based on scientific research. This is what the science says:
Wait to apply lawn fertilizer in north Florida until mid-April. Lawn grasses don’t have sufficient root growth and capabilities to use the fertilizer until then. Applying fertilizer earlier in February and March feeds the winter weeds or is lost to leaching down into the soil below the grass roots. Here’s more detail on fertilizing your lawn.
Weed and feed products are not recommended. Instead, spot treat weeds when they are small before they mature and set seed. Consult our Weed Management Guide.
Preemergence herbicide, if applied correctly, can cut down on the weeds. Apply in late February or first of March for summer weeds and October 1 for winter weeds. Now in late March – Early April is still a good time to use a preemergence herbicide for those weeds that have not yet sprouted. It is crucial to apply the product correctly, following all label directions. Measure your lawn and make sure the right amount of product is applied. This is a convenient way to measure your lawn from your armchair.
Sharpen your mower blades! A clean cut on the grass blade cuts down on lawn stress and diseases setting in.
Water efficiently. We see more damage to lawns from overwatering than underwatering. Overwatering leads to increased weeds, disease, insect pests and weakens grass roots. Lawns need ½” to ¾“ of water and this will tell you how to determine when to water. The root system is healthier and stronger when watered deeply only when it needs it. Learn how long it takes your sprinkler system to deliver that amount.
The University of Florida provides more advice and information at:
Most lawn weeds are annoying, appearing in unwanted places and numbers, but few actually cause physical harm like the pest plant Lawn Burweed (Soliva sessilis)! This infamous small, spreading winter weed’s seeds generally germinate when temperatures begin to cool in the fall (late October-November). Burweed then grows mostly unnoticed through the winter until spring, when it then produces the hard, spiny burs that contain the plant’s seeds and the plants finally die. Once the burs have formed, Burweed’s presence makes walking on newly greened-up spring turf extremely painful for pets and people (barefoot of course, the burs aren’t large enough to puncture shoe soles). At this point of the plant’s life, once it has made its unwanted presence known, control is not feasible as the Burweed plants have set seed, ensuring a new crop next year, and killing the remaining foliage doesn’t remove the burs. What is a homeowner to do?
Newly germinated Lawn Burweed. Photo courtesy of the author.
Fortunately, Lawn Burweed is relatively easy to control chemically if one pays close attention to seasonal changes and uses herbicides (either pre-emergent or post-emergent herbicides) effectively.
Pre-emergent Herbicide Options: The first chemical control option for Lawn Burweed is a timely application of the pre-emergent herbicide Isoxaben (sold under various brand names at most farm or garden stores) to prevent Burweed seeds from germinating, greatly reducing plant populations. However, pre-emergent Isoxaben applications must be made before the plants sprout and begin to grow to be effective. For Burweed, this generally means application in October, once nighttime temperatures dip into the 55-60 degrees F range for several nights in a row, as consistent temperatures in this range give Burweed seeds the signal to germinate. Though we’re already past the point of pre-emergent herbicides being an option for control this year, homeowners should plan to include this method in their Lawn Burweed control plan for fall 2020!
Post-Emergent Herbicide Options: If you haven’t already used a pre-emergent herbicide this fall for Burweed control, you must turn to post-emergent options. Like pre-emergent herbicides, timing is critical if you want your post-emergent applications to work! These herbicides are most effective when Burweed plants are young, small, vigorously growing, and haven’t set burs yet. Successful post-emergent applications may be made from December-early February before burs harden. Unlike pre-emergents, where there is only one strong option for Burweed control, many post-emergent herbicides exist that are extremely effective! When shopping, look for products containing the following active ingredients:
Lawn Burweed around 10 days after emergence. Photo courtesy of author.
Atrazine – sold under many brand names and safe in Centipede, St. Augustine, & Bermudagrass. Do not use in Zoysia or Bahiagrass lawns.
Dicamba, Mecoprop, 2,4-D – commonly sold in three-way formulations through many brand names. Generally safe in Centipede, St. Augustine, Bermuda, Zoysia, & Bahiagrass lawns.
Metsulfuron – sold under several brand names and safe in Centipede, St. Augustine, Zoysia & Bermudagrass. Do not use in Bahiagrass. Be careful if used around ornamentals.
Thiencarbazone, iodosulfuron, dicamba – sold as Celsius WG from Bayer. Safe in Centipedegrass, Zoysiagrass, Bermudagrass, and St. Augustinegrass. Do not use in Bahiagrass.
Lawn Burweed control with of all the above-listed herbicides will be most effective with a follow-up application 10-14 days later.
Note: With the exception of the Thiencarbazone, iodosulfuron & dicamba mixture (Celsius), do not apply any of these post-emergent herbicides during spring turf green up.
For a state that receives around 60” of rainfall a year, it is sure dry in Florida right now! In the Panhandle, the majority of our annual rainfall occurs in in bunches during winter and early spring via near-weekly cold fronts, in the mid-summer as a result of afternoon thunderstorms, and periodically in late summer/early fall if a tropical system crosses our path. Mixed in, however, are two distinct, historically dry periods: the first one in April through mid-May (contrary to popular myth, if we have May flowers, they’re gonna have to make it without April showers) and the second right now in September and October. The prolonged second dry period that we’re experiencing now makes it difficult to manage the mostly unirrigated, low-input turfgrass common in rural Panhandle lawns and pastures. It is critical to enter these expected droughts with healthy turf and remembering to employ 3 simple management tips when it quits raining (although you should follow them year-round ideally) can greatly increase your turf’s resiliency!
Unirrigated Centipdedegrass turf showing drought stress- Photo courtesy of the author.
Water Wisely – The average Florida turfgrass requires ¾-1” of water per week and we generally achieve that through rainfall. However, in our droughty months, supplemental irrigation can be a lawn saver, particularly in high traffic or more stressed areas of the yard. I realize that many of you, myself included, maintain large lawns without irrigation systems and it’s impossible to keep all your lawn well-watered during drought, but you can maintain the areas around your home, hardscapes and landscaped beds with the highest impact/visibility nicely! In these areas, put down no more than ¾” of water per irrigation event, a ballpark number that ordinarily allows the turf root zone to become saturated. Measuring your sprinkler’s water output is easily done by setting several straight-sided cans (tuna or cat food containers work great) under the sprinkler and timing how long it takes to achieve 3/4”. You might be surprised how much water you waste by leaving a sprinkler running for an hour or more!
Apply Herbicides Appropriately – Herbicides are a great item to have in the turf care toolbox, but if used incorrectly can be a waste of time and money at best, harmful to your turf at worst! Once turf and associated weeds become drought stressed (turning bluish gray, obvious wilting, leaves curling, etc.), it is too late for weed control with herbicides. There are a couple of reasons for this. First, when plants get stressed, they slow or stop their growth and focus on survival. This survival response prevents herbicides from being taken up properly and ultimately causes ineffectual weed control. Also, many herbicides specifically state on the product label that they should not be applied during certain conditions (drought, temperatures above 85-90 degrees, etc.). It is critical that one adhere to these label directions as applying the incorrect product in hot and dry conditions can cause volatility, drift to non-target plants, and in some cases, toxicity to turf you’re treating in. When it’s droughty like it is now, leave the herbicides in the chemical shed to prevent wasting your time and money and potentially damaging non-target plants!
Unirrigated Centipedegrass turf showing drought stress – photo courtesy of the author
Raise that Deck – Finally, one of the most important turf management strategies during an extended drought is to reduce mowing and raise your mower’s cutting height when/if you do mow. As mentioned above, plants are already stressed during a drought and physically chopping off a chunk of the turf plant stresses it further, causing an energy-intensive wound response when the plant is actively conserving resources for survival. Therefore, if you just HAVE to mow, raise the cutting height as high as possible to make the smallest injury possible on the grass and keep your mower blades sharp to ensure a clean cut, which will heal easier and require a smaller energy response from the plant.
During droughts like the one we’re currently in, there isn’t one silver bullet to keep your non-irrigated turf looking good. However, there are several strategies you can use throughout the year to get your lawn through dry times. Remember to water ¾”-1” per week when you can, where you can. Before you water, calibrate your sprinkler to ensure you put out enough water and don’t waste your time and inflate your utility bill by putting out too much! Reduce or eliminate use of herbicides as they are ineffective during stress periods and can harm your turfgrass. Finally, reduce or eliminate mowing and if you must mow, raise the deck! If you have any questions about getting your turf through the drought or other horticultural or agronomic topics, please contact your local UF/IFAS Extension Office!
Weeds identification and management is still one of the most common questions we receive at the local UF IFAS Extension office. Learn about the chamberbitter weed that can grow in turf and ornamental beds and the multi faceted approach that is necessary for management In the Garden with Beth Bolles, UF IFAS Extension Escambia County.
Seldom do we find the answer to a problem as being easy. More often, a difficult and complicated answer is what’s needed. However, the solution to a healthy lawn rebound may be found simply by adjusting your mower height and mowing schedule.
Mowing strategy is an important variable that keeps a lawn healthy and flourishing, no matter the species or cultivar of grass. Mowing too high can lead to an undesirable look and cause unwanted thatch buildup, which can create a favorable environment for pests and diseases. Mowing too low can weaken the root system causing thinning, which allows space for weeds to invade. Another problem with mowing too low is that it affects nutritional needs. Lawn grasses generate food for themselves through a process called photosynthesis. A healthy leaf surface area is needed to effectively accomplish this. If the lawn is mowed too low, then leaf surface area is lost. The grass can literally starve itself.
Table: Suggested mowing height for lawn grasses. Frequency of cut will vary based on species and time of year. Credit: L. E. Trenholm, J. B. Unruh & J. L. Cisar, UF/IFAS Extensio
Not all lawn grasses should be mowed at the same height, as show in the table above. Fine textured grasses like Bermuda and Zoysia matrella can be cut significantly lower than coarse textured grasses, such as Bahia or St. Augustine. Not sure of the type of lawn grass you have? Visit this site https://edis.ifas.ufl.edu/topic_book_florida_lawn_handbook_3rd_ed to review the Florida Lawn Handbook or contact your local county extension office for questions.
Mowing schedule is the other side of the coin. How often to mow ultimately depends on how fast your grass grows. By nature, Bermuda will grow quickly and Zoysia is somewhat slower growing. Regardless, summer months are when warm-season lawn grasses grow more rapidly. Historically, lawn grasses begin a dormant-slow growth stage in October and continues through March. Fertilizer schedule also plays a role in grass growth rate. So how often do you need to mow? This rate is best determined by the amount of growth since the last cutting, rather than the number of days which have elapsed. You should mow often enough so that no more than 1/4 to 1/3 of the total leaf surface is removed at any given mowing. In other words, leave twice as much leaf surface as you cut off. Remember, incremental adjustments should be made to your current practices. Never drastically change the height of the grass. If the lawn has been allowed to grow too long, you should gradually lower the mowing height on successive cuttings.
What are some other helpful tips? Always use a well-adjusted mower with a sharpened blade. You may find it easier replace your blade each year or every 2 years than periodic resharpening. Dull mower blades do a tremendous amount of damage with uneven cuts. This will cause gashes and splits in the leaf where fungal and bacterial pathogens can thrive. Never mow grass when it’s wet, either. Dry grass cuts are cleaner cuts and won’t clog the mower deck. If you have built up thatch, it’s a good idea to attach a bag to your mower that will catch clippings. These clippings will be great additions to your compost pile or to use as natural mulch. If no thatch problems exist, mowing without a bag will distribute clippings throughout the lawn, and the clippings will decompose into nutrients for the root system.
With proper mowing strategies, along with fertilizing & watering, your lawn grass can bounce back. For more information contact your local county extension office.
Information for this article provided by the UF/IFAS Extension EDIS Publication, “Mowing Your Florida Lawn”, by L. E. Trenholm, J. B. Unruh & J. L. Cisar: https://edis.ifas.ufl.edu/pdffiles/LH/LH02800.pdf
UF/IFAS Extension is an Equal Opportunity Institution.
