Timing is Everything when Controlling Lawn Weeds

Timing is Everything when Controlling Lawn Weeds

Hot, summer months are not the time to be using most lawn herbicides.

One issue is the heat of summer. Most lawn herbicide labels include statements such as the following.

“Do not apply when temperature exceeds 90°F.” “Do not broadcast apply this product when air temperatures are above 90°F (85°F for St. Augustinegrass) unless temporary turf injury can be tolerated.”

Every year we’ll see lawns that are injured or killed because of lawn herbicides being applied when temperatures are too hot.

Summer is usually a rainy and windy time of the year. Many lawn herbicide labels include statements such as the following.

“Allow 12 hours after application before watering lawn for maximum effectives on listed weeds.” “Apply only when wind is no more than 10 mph.” “Applying this product in calm weather when rain is not predicted for the next 24 hours will help to ensure that wind or rain does not blow or wash pesticide off the treatment area.”

It is critical to read and follow the label directions and precautions for any pesticide you use. Pesticide labels, including herbicides, include the following statements.

“To the extent consistent with applicable law, the buyer assumes all risks of use, storage, or handling of this product not in accordance with label directions.” “It is a violation of Federal law to use this product in a manner inconsistent with its labeling.”

Crabgrass plant growing in centipedegrass lawn

Crabgrass growing in centipedegrass lawn. Photo credit: UF/IFAS Extension

By the time summer arrives, many of the lawn weeds are mature, which means they are well established with extensive root systems. These mature, well established weeds are much more difficult to control. They are more susceptible to herbicides when they are small, young, and not well established. Also, these mature weeds have been allowed to produce countless numbers of seeds as they move into summer. Most weeds are prolific seed producers. For example, a single crabgrass plant (a common summer lawn weed) can produce 150,000 seeds.

Applying a preemergence lawn herbicide in February to help prevent summer annual weeds such as crabgrass or applying a postemergence lawn herbicide during spring while the weather is mild and before the weeds are out of control simply makes more sense than waiting until summer.

The best options now with lawn weed control involve continuing to follow good mowing practices, maybe hand removal of some weeds, and just simply waiting it out until next February and spring to worry with the use of lawn herbicides.

In the meantime, you may want to read the following UF/IFAS Extension publication on lawn weed control.

https://edis.ifas.ufl.edu/pdf/EP/EP14100.pdf

Larry Williams, UF/IFAS

Five Reasons for Lack of Fruiting in Figs

Five Reasons for Lack of Fruiting in Figs

Q. One of my two fig trees has produced a few figs. The other one, which is the largest and healthiest tree, has never had a fig on it. Both where planted six years ago. Why is it not producing?

Section of mature fig tree with ripe fruit

Mature fig tree with fruit. Photo credit: Larry Williams

A. It may be a matter of age and being overly vigorous. When a fruit tree is younger, it puts most of its energy into producing leaves and shoots. Until the plant becomes mature and slows down in the production of leaves and shoots, it will produce few to no fruit. It may take a year or two more for your tree to slowly and gradually switch from producing mostly leaves and shoots to producing and maturing some fruit. Patience is needed.

Be careful to not overdo it in fertilizing and/or pruning your fig tree. Too much fertilizer, especially nitrogen, or severely pruning the tree will result in the tree becoming overly vigorous at the expense of setting and maturing fruit. This includes fertilizer that the tree may pull up from a nearby lawn area. A tree’s roots will grow outward two to three times beyond its branch spread into adjacent lawn areas.

The end result of being heavy handed with fertilizing and/or overdoing it in pruning is the same – it forces the plant to become overly vigorous in producing leaves and shoots at the expense of producing and maturing fruit.

In addition, the following is taken from an Extension publication on figs and includes the most common reasons for lack of fruiting, in order of importance.

  1. Young, vigorous plants and over-fertilized plants will often produce fruit that drops off before maturing. If plants are excessively vigorous, stop fertilizing them. Quite often, three of four years may pass before the plant matures a crop because figs have a long juvenile period before producing edible quality fruit.
  2. Dry, hot periods that occur before ripening can cause poor fruit quality. If this is the case, mulching and supplemental watering during dry spells will reduce the problem.
  3. The variety Celeste will often drop fruit prematurely in hot weather regardless of the quality of plant care. However, it is still a good variety to grow.
  4. An infestation of root-knot nematodes can intensify the problem when conditions are as described in item 2.
  5. You could have a fig tree that requires cross-pollination by a special wasp. This is a rare problem. If this is the case, then it will never set a good crop. The best way to resolve this is to replace the plant with a rooted shoot of a neighbor’s plant you know produces a good crop each year.
Don’t Blame Pests for Dry Spots in Your Lawn

Don’t Blame Pests for Dry Spots in Your Lawn

Every time we have a dry period in spring or summer, I get those predictable calls about some mysterious pest that’s playing havoc in lawns.

 

Dry areas in lawn that show up during dry periods from imperfections in irrigations system

Dry spots in lawn. Photo credit: Larry Williams

Without realizing it, the caller usually describes a textbook example of dry spots in a lawn. And many times that’s what the problem areas are – dry spots.

 

Dry spots are the result of imperfections in an irrigation system. They are revealed during dry weather. Adequate rainfall masks the imperfections in an irrigation system.

 

Possible imperfections are many. The homeowner may easily fix some irrigation system problems while other problems may require the expertise of a licensed irrigation contractor. There may be too few sprinkler heads for adequate coverage, insufficient pressure to operate each zone, incorrect choice of nozzles or wrongly mixing rotors with spray heads on the same zone. The cause for dry spots may be as simple as a maladjusted spray head, a broken spray head, a plugged nozzle, a tree or shrub blocking the water, grass that has grown over a pop-up spray head, etc.

Regardless of the cause, there are a couple of simple tests that can help confirm that the problem areas are to be blamed on lack of sufficient water vs. a mysterious pest.

First, check the affected areas by taking a soil sample in the root zone. Use a soil probe or shovel to remove a core of soil to a depth of 6 to 8 inches. Visually inspect and feel the soil sample for moisture. Do the same test in an area of the lawn that looks normal and compare the difference. It should be obvious if there is a difference in moisture between the areas tested.

The second test involves placing several empty straight-sided cans such as tuna fish cans in the affected area and several in a “normal” area of the lawn. Then let the irrigation system run long enough to collect some water in the cans. Compare the amount of water collected in the two areas. It should be obvious if there is a difference in the amount of water applied in the areas tested.

These tests are cheaper, less trouble and more environmentally friendly as compared to purchasing and applying pesticides for nonexistent pests as a result of incorrectly diagnosing the problem. If these tests do not identify the problem as lack of water, you may have a lawn pest. But don’t guess.

Occasionally inspect your irrigation system while it’s running for obvious, easily corrected problems such as a maladjusted or broken spray head. The following UF/IFAS Extension publications will help with your inspection. https://edis.ifas.ufl.edu/entity/topic/residential_sprinkler_systems

North Florida Lawns are Frustrating

North Florida Lawns are Frustrating

I’ll be the first to admit that North Florida lawns are frustrating. With time, most people discover this.

Why are lawns so difficult here? The answer involves a combination of factors.

We are not far enough north to benefit from the better soils. Florida is known for sandy, low fertility, low water holding capacity soils. Some areas of the country enjoy richer soils with better water and nutrient holding capacities. These better soils result in a more favorable lawn root environment with roots being more competitive and resilient.

Something else happens in more northern areas. The heavier soils and colder temperatures (sometimes resulting in the soil freezing) are natural means of inhibiting and/or controlling certain soil dwelling pests. For example, nematodes are not nearly the concern in northern lawns. Many people that move to our area have never heard of these microscopic roundworms that play havoc in our low fertility, warm, sandy soils. After a lawn has been in place for a number of years, allowing the nematode population to reach a threshold, the lawn begins to decline. And we have few legal, effective chemical control options for nematodes in Florida lawns.

Dying area in lawn due to ground pearls

Declining area in lawn due to ground pearl. Photo credit: Larry Williams

Some other soil dwelling pests that northerners don’t have to deal with include ground pearls, small scale-like insects that bother centipedegrass roots. Mole crickets are not a pest much north of Central Alabama. Years ago, a representative with the company that manufactured the once popular mole cricket insecticide Oftanol told me that in the absence of the state of Florida, they would not sell enough Oftanol to keep it on the market. Take-all Root Rot, a common soil dwelling fungus, plays havoc in our Florida lawns and it is difficult to control.

We are not far enough north to use the more trouble-free northern grasses to create a permanent lawn. These include bluegrasses, fescues and perennial ryegrass. At best, these grasses can be used to overseed our lawns during the cooler fall and winter months to create a temporary winter lawn. But they will not survive our hot, wet summers.

We are not far enough south to benefit from the lack of freezing temperatures during winter. A late freeze that occurred on April 8 a number of years ago resulted in much lawn injury. I saw lawns with seventy percent kill from this late freeze. This is something that typically does not happen in Central and South Florida.

We deal with saltwater issues, high humidity, hurricanes and tropical storms, an array of lawn insects and diseases and extremes in rainfall and temperatures.

It’s no wonder most people become dissatisfied with their lawns. Perhaps we should lower our expectations and enjoy the natural flora and fauna of our state.

Winter Annual Weeds, a Great Place to Hide Easter Eggs

Winter Annual Weeds, a Great Place to Hide Easter Eggs

As a boy in a small town in Georgia we had a St. Augustinegrass lawn. My dad started the lawn before I was born. That lawn was still doing fine when I left for college at age seventeen. I don’t remember weeds in the lawn during summer months. I do fondly remember winter “weeds” in that lawn.

To see clumps of winter annuals in our yard and in neighbors’ yards was a natural part of the transition from winter to spring. They added interest to what

Bluish Easter egg hidden in chickweed

Blue Easter egg hidden in chickweed. Photo credit: Larry Williams

would have been a plain palette of green. It was expected to see henbit with its square stiff stems holding up a display of small pinkish purple flowers in late winter and early spring. A clump of henbit was a great place to hide an Easter egg, especially a pink or purple one.

Wild geranium, another common winter annual, offered another good hiding place for Easter eggs with its pink to purple flowers. Large clumps of annual chickweed would nicely hide whole eggs. Green colored eggs would blend with chickweed’s green leaves.

Pink Easter egg hidden in crimson clover and hop clover mix

Pink Easter egg hidden in crimson clover & hop clover mix. Photo credit: Larry Williams

Crimson clover with its reddish flowers, hop clover and black medic with their bright yellow flowers were good hiding places for Easter eggs. Plus clovers add nitrogen back to our soils.

I never remember my dad using any weed killer, he rarely watered. The lawn was healthy and thick enough to be a deterrent to summer weeds. But during fall and winter as the lawn would naturally thin and go dormant, winter annual weeds would run their course.

I’ve heard that the sense of smell provides our strongest memories. I remember the first mowing of the season with the clean smell of chlorophyll in the spring air. It was refreshing. Once mowed and as the heat took its toll, by late April or mid-May, these winter annual weeds were gone. What was left was a green lawn to help cool the landscape as the weather warmed. The lawn was mowed high as St. Augustine should be, played on and typically not worried with.

Most people have winter weeds in their lawns that let us know spring is near. Perhaps we worry too much with these seasonal, temporary plants that may have wrongly been labeled as weeds. Besides, how long have we been doing battle with these weeds and they are still here. Most lawns have countless numbers of winter annual seeds awaiting the cooler temperatures and shorter days of early winter to begin yet another generation. By May they are gone.