Setting the sprinkler head for an irrigation system. UF/IFAS Photo: Josh Wickham
Lawns and landscapes require water to flourish and provide the green surroundings desired around homes and recreational areas. Often nature provides water for the landscape in the form of rain, but that is not always adequate. Turf and ornamental plants in the establishment stage need supplemental irrigation during hotter months, especially in the sandy soils of northwest Florida, which can dry out at a rapid pace. February is typically a time when very little supplemental irrigation water is needed because most of the desired landscape plants and grasses do not use much water in the cooler temperatures. The warmth of spring and the heat of summer are around the corner and preparations should be made now to ensure that irrigation systems are working properly before being needed. Here are a few things to think about when prepping irrigation systems for spring:
Maintain, Repair, or Replace the Rotors, Nozzles, and Heads. Many sprinkler heads get damaged over time from riding lawn mowers, utility workers, vehicles, or other causes. To avoid having a geyser in the irrigation zone, it is a good idea to test run the system to make sure the rotor and heads are working properly and the nozzles have not been knocked loose. Many times broken rotor or spray heads can be replaced simply by taking the interior mechanical parts out and replacing them with new parts. This may not even require digging! Sometimes repairs are as simple as replacing a filter or spray nozzle that has popped off over time.
Calibrate the system to provide 1/2 inch to 3/4 inch during an irrigation event. Many Florida homeowners and horticultural professionals apply too much or too little water while irrigating. Most do not even know how much irrigation water is being applied. It is important to calibrate the irrigation system to apply only 1/2 inch to 3/4 inch of water during an irrigation event to promote a healthy lawn and landscape. To little water will stress the plants while too much water may promote disease and insect problems. Irrigating improperly may also cause environmental issues, from soil and fertilizer runoff, to develop. Watch this short video on irrigation calibration.
Inspect and make sure the Rain Shutoff Device is working properly. In Florida, it is state law to have a rain shutoff device on an automatic irrigation system. Most systems have a device installed that utilizes a small cork disc that expands when wet and physically clicks a button to tell the system to skip the next automatic cycle. As the cork degrades over time, it will cause system malfunction and should be replaced periodically. It is best to skip using an automatic timer and instead watch the weather and the plants for symptoms of drought stress. If an automatic timer is used, a functioning rain shutoff device is essential for proper irrigation management. Other types of shutoff devices are available as well.
The following University of Florida / IFAS publications contains more information on proper irrigation management for landscapes:
Though the calendar says December, the weather in Northwest Florida fluctuates between winter and spring temperatures. The nice days are wonderful opportunities to accomplish many of those outside landscape chores in preparation for spring. But, it is also a good time to start planning for next month’s colder temperatures. Since we don’t experience frozen soil, winter is the best time to transplant hardy trees and shrubs. Deciduous trees establish root systems more quickly while dormant; versus installing them in the spring with all their tender new leaves. Here are a few suggestions for tasks that can be performed this month:
Plant shade trees, fruit trees, and evergreen shrubs.
Plant pre-chilled daffodil and narcissus bulbs (late December/early January).
Do major re-shaping of shade trees, if needed, during the winter dormancy.
Water live Christmas trees as needed and water holiday plants such as poinsettias as needed.
Check houseplants for insect pests such as scale, mealy bugs, fungus gnats, whitefly and spider mites.
Continue to mulch leaves from the lawn. Shred excess leaves and add to planting beds or compost pile.
Replenish finished compost and mulch in planting beds, preferably before the first freeze.
Switch sprinkler systems to ‘Manual’ mode for the balance of winter.
Water thoroughly before a hard freeze to reduce plants’ chances of damage.
Water lawn and all other plants once every three weeks or so, if supplemental rainfall is less than one inch in a three week period.
Fertilize pansies and other winter annuals as needed.
Protect tender plants from hard freezes.
Be sure to clean, sharpen and repair all your garden and lawn tools. Now is also the best time to clean and have your power mower, edger and trimmer serviced.
Be sure the mower blade is sharpened and balanced as well.
Provide food and water to the area’s wintering birds.
“We have replaced this grass several times over the past few years; and it’s dying again.” I have heard this complaint too many times this summer. Last summer’s heavy rain, the stress of January’s icy weather, and this year’s extended summer have contributed to widespread outbreaks of Take-All Root Rot, a soil-inhabiting fungus Gaeumannomyces graminis var. graminis.
Symptoms of Take-All-Root-Rot. Photo credit: Sheila Dunning, UF/IFAS.
This disease causes yellow grass patches ranging in diameter from a few inches to more than 15 feet. The symptoms first appear in the spring, but the disease can persist all summer and survive the winter. Over time, the entire area dies as the root system rots away. The pathogen is naturally present on warm-season turfgrass roots. High rainfall and stressed turfgrass trigger the disease.
Since the roots are affected, they are not able to efficiently obtain water or nutrients from the soil, nor are they able to store the products of photosynthesis, which result in the loss of color in the leaves. By the time the leaf symptoms appear, the pathogen has been active on the roots for several weeks, probably longer; the disease has been there potentially for years. If the turfgrass is not stressed, leaf symptoms may never be observed.
This disease is very difficult to control once the aboveground symptoms are observed. Measures that prevent or alleviate stress are the best methods for controlling the disease. Any stress (environmental or manmade) placed on the turf weakens it, making it more susceptible to disease. Remember, that every maintenance practice, fertilizer application, and chemical (especially herbicide), application has an impact on turfgrass health. Cultural practices that impact the level of stress experienced by a lawn include:
proper turfgrass species selection
mowing at the correct height
irrigation timing, frequency and volume
fertilizer: nitrogen and potassium sources and application quantities
thatch accumulation, and
soil compaction
The selection of turfgrass species should be based on existing soil pH, sunlight exposure, use of the area and planned maintenance level.
Mower blades must be sharp to avoid tearing of the leaves. Additionally, turfgrasses that are cut below their optimum height become stressed and more susceptible to diseases, especially root rots. When any disease occurs, raise the cutting height. Scalping the grass damages the growing point. Raising the cutting height increases the green plant tissue available for photosynthesis, resulting in more energy for turfgrass growth and subsequent recovery from disease.
If an area of the lawn has an active fungus, washing or blowing off the mower following use will reduce the spread of the disease to unaffected areas.
The amount of water and the timing of its application can prevent or contribute to disease development. Most fungal pathogens that cause leaf diseases require free water (rainfall, irrigation, dew) on the leaf to initiate the infection process. Irrigating every day for a few minutes is not beneficial for the turfgrass because it does not provide enough water to the root zone, but it is beneficial for turfgrass pathogens. It is always best to irrigate when dew is already present, usually between 2 and 8 a.m., and then only apply enough water to wet the root zone of the turfgrass.
Excessively high nitrogen fertility contributes to turfgrass diseases. The minimum amount required for the grass species should be applied. Potassium (K) is an important component in the prevention of diseases, because it prevents plant stress. Application of equal amounts of nitrogen and potassium is recommended for turfgrass health. When turfgrass roots are damaged from disease, it is beneficial to apply nutrients in a liquid solution. However, nitrate-nitrogen increases the severity of diseases, so their use should be avoided when possible. Ammonium-containing fertilizers are the preferred nitrogen sources.
Heavy liming has also been linked to increases in Take-All Root Rot. Since most turfgrasses can tolerate a range of pH, maintaining soil at 5.5 to 6.0 can suppress the development of the pathogen. When the disease is active, frequent foliar applications of small amounts of nutrients is necessary to keep the turfgrass from declining.
Additional maintenance practices that need to be addressed are thatch removal and reduction of soil compaction. Excessive thatch often causes the mower to sink which can result in scalping and reducing the amount of leaf tissue capable of photosynthesizing. Thatch and compacted soil prevent proper drainage, resulting in areas remaining excessively wet, depriving root systems of oxygen. Since recovery of Take-All-Root-Rot damaged turfgrass is often poor, complete renovation of the lawn may be necessary. Removal of all diseased tissue is advised.
As a native soil-inhabiting pathogen, Take-All-Root-Rot cannot be eliminated. However, suppression of the organism through physical removal followed by proper cultivation of the new sod is critical to the establishment of a new lawn. Turfgrass management practices, not chemicals, offer the best control of the disease.
It is acceptable to use fungicides on a preventative basis while rooting in the sod. Azoxystrobin, fenarimol, myclobutanil, propiconazole, pyraclostrobin, thiophate methyl, and triadimefon are all fungicides that can be utilized to prevent disease development while having to excessively irrigate newly laid sod. Ideally, the turf area should be mowed and irrigated prior to a fungicide application. Unless the product needs to be watered in, do not irrigate for at least 24 hours after a chemical treatment. Do not mow for at least 24 hours, to avoid removal of the product attached to the leaf blades.
With all the stresses that our lawns have experienced, it is very important to continue monitoring the turf and be cautious about the cultural practices being used. Take-All Root Rot is likely to flourish. Do not encourage its development. A pathology test with the University of Florida Laboratory can confirm the presence of the disease causing organism. Before resodding again, have the dying sod tested.
A frozen perennial plant. Photo credit: Taylor Vandiver UF/IFAS Extension.
When you look out at your landscape nobody has to tell you that winter temperatures in Northwest Florida Afterwards, the temperatures warm up and you feel compelled to do something about it. You just need to “turn your back and slam the door”. “Conceal, don’t feel; don’t let them know”. Cold injury can affect the entire plant or just certain plant or parts such as fruits, flowers, buds, leaves, trunks, stems, or roots. Many plant parts can adapt to tolerate cold. Root systems in the landscape are seldom ‘frozen’ in Florida. “The cold never bothered” them “anyway”. While dead, unsightly leaves may be removed as soon as they turn brown after a freeze, the remaining dry looking stems serve as food storage and should be allowed to remain. If they are removed before the weather is warm enough for the plant to resume growth, the root system may not be enough to support the plant and it will die. So, “let it go, let it go, let it go”. “The perfect” landscape “is gone”. “The past is in the past”. “It’s funny how some distance makes everything seem so small”.Tropical plants and summer annuals do not adapt or harden to withstand temperatures below freezing, and many suffer injury at temperatures below 50°F (10°C). Subtropical plants can harden or acclimate (become accustomed to a new climate) to withstand freezing temperatures, and properly conditioned temperate plants can withstand temperatures substantially below freezing.
Recently planted, unestablished plants may be more susceptible to cold injury. One type of winter injury is plant desiccation or drying out. This is characterized by marginal or leaf tip burn in mild cases and totally brown leaves in severe cases. Desiccation occurs when dry winds and solar radiation result in the loss of more water from the leaves than can be absorbed and/or transported by a cold root system. Plant water needs should be checked after a freeze. Plants may have lost substantial moisture during a windy freeze. Plants will transpire (lose water vapor) on a sunny day after a freeze. Cold injured wood can be identified by lightly scraping the bark with your fingernail and examining the color of the cambium layer (food conducting tissue) just underneath. Green tissue indicates the plant is still alive at that point; black or brown coloration indicates dead or injured tissue.
After a particularly harsh cold event, some plants may be very slow to recover, so some patience is required. “It will rise” with “the break of spring”. Branch tips may be damaged while older wood is free of injury. Delay pruning until new growth appears next spring to ensure that live wood is not removed. In the meantime, take Elsa’s advice and “let it go, let it go, let it go”. You may be “too relieved to grieve”. I hope I haven’t infringed on any copyrights by letting you know “It’s okay to put off the yard work in the name of plant physiology”.
Many of us have a tendency to want to spoil those we care for – our significant other, our pets, our children, even our lawns. Some homeowners who long to have a lush, green, healthy lawn tend to spoil their lawns with lots of water. Their lawns should not suffer through a dry, thirsty day! However, spoiling a lawn with too much water can literally be killing it with kindness. (Keep in mind that we are discussing established turf, not newly installed lawns; new lawns do need special care.)
Turfgrass that is overwatered can suffer several fates. Roots can stay shallow near the surface and not dig deep into the soil as they should. A deep root system allows the turf to be more resistant to stress from drought, disease and abiotic factors such as wear from traffic. Excessive water leads to excessive lush growth – that may sound like a good thing, but it’s not. Excessive lush growth leads to thatch build-up and it creates a perfect environment for pests and diseases. An abundance of water also assists those nasty weed seeds to germinate and compete with your turfgrass.
So how do you know how much irrigation is best for the health of your lawn? That depends on the temperature, time of year, the type of turf and your soil type. Irrigate just enough to get water to the root zone without leaching beond that zone. Usually, that amount is 1/2″ to 3/4″ of water each time you irrigate. How often, then, do you turn on those sprinklers?
Let your lawn get thirsty before you water. University of Florida research shows that lawns that dry out and start to show a little drought stress before getting more water actually perform better in the long run. So wait until the leaf blades start to fold, the blades start to look a bit off-color, or you can start to see footprints where you’ve walked.
For lots of great information and publications on caring for your lawn, consult the Your Florida lawn website.
