One of the most exasperating landscape challenges for homeowners can be what seems like it should be the easiest of tasks: growing grass. For many, though, growing grass isn't so easy.
Sometimes the problem is bare spots where grass stubbornly refuses to grow. In other cases, the entire lawn — despite hours of effort and money spent on grass seed, fertilizers and pre- and post-emergent — resembles a weed-filled field. (And for some people, a well-mowed weed lawn works just fine.)
But an ugly lawn can be especially frustrating for homeowners who have a neighbor with a streetscape that looks like it belongs on the cover of a home and garden magazine or for people who must abide by strict homeowner association (HOA) rules. It's not unusual for HOA covenants, for example, to require that a percentage of the property be not just grass but grass grown and cut in a certain way.
But what if you can't get grass to grow, no matter how hard you try? While your first instinct might be to wonder what you're doing wrong, don't be too quick to blame yourself. There's a good chance it's not your fault.
"Sometimes, sites just aren't conducive for turf," said Clint Waltz, an extension turfgrass specialist at the University of Georgia's Turfgrass Research & Education Center in Griffin, Georgia. "Be willing to accept that whenever it presents itself."
Waltz said there are five primary reasons grass won't grow. Here's how he ranks them based on conditions he encounters when visiting property owners who have called him for help.
1. Lack of sunlight or a shaded environment
2. Competition from tree roots
3. Compacted soil
4. Underground objects (a variation of a theme with No. 2)
5. Lack of air flow, which Waltz also calls air drainage
In these situations, Waltz said he tells homeowners probably the last thing they want to hear. "I've had to tell people that this just isn't a suitable site for turf," he said. "It would be nice if it was, but it's not. Grass will always be a challenge here."
To help you overcome Waltz's top five challenges to growing grass, here's a look at each of them and what he suggests you can do about them.
Lack of sunlight, a shaded environment
The first thing to do when grass isn't growing well — or not at all — is don't look down, advises Waltz. Look up. The most common issue he sees with problem turf is a lack of sunlight. Trees that have matured, hedges that were planted as privacy screens or even nearby buildings are examples of objects that cast too much shade on sun-loving turf — even if that wasn't always the case.
"Many times folks will tell me, 'Gosh, I had the prettiest lawn 15 years ago,'" said Waltz. "What they tend to forget is that landscapes mature with time. So, that little oak tree or maple that was about head high and barely 5 foot tall 15 years ago is now 25 feet tall, and it's grown into about an 8-inch caliper tree."
In situations like this, he said homeowners will lose grass with time as landscapes mature and areas that once were in full sun gradually become shadier and shadier. "This is a very common thing," said Waltz. "Landscapes mature, and those lawns that looked good 10, 15, 20 years ago aren't looking so good now."
A similar problem can happen when a homeowner plants a sun-loving grass in a landscape that already has mature trees. It's important for homeowners to remember that the horticultural mantra of Right Plant, Right Place applies to grass as much as to any other plant, said Waltz. You must put the right plant — grass, in this case — in the right place to have some reasonable expectations of success, he emphasized. "If you don't, you're going to have problems, and it's going to be a struggle."
Luckily for homeowners, there's diversity within the turf species. While some grass plants require eight hours-plus of full sun a day during the growing season, others are fine at handling limited light.
All warm-season grass species — Bermuda grass is an example — perform well in full sun. But some warm-season grasses can handle limited-light environments, or even shade. Some zoysia grasses can take five to five and a half hours of intermittent sun during the growing season to maintain what Waltz calls commercial acceptability.
If shade is the reason you can't get grass to grow, Waltz offers several remedies. The first solution assumes you're not going to cut down the offending tree or hedge. That solution would be to find a more shade-tolerant turf for your environment. Another option would be to increase your mowing height a little bit in the shaded areas.
But if you have a sun-loving grass such as Bermuda grass and part of the lawn isn't growing well because the problem area is in shade, the solution will be to remove the turf. In that case, Waltz suggests changing your landscape design and extending the bed line to include the shaded area.
Then, in the area inside the new bed line where the grass wasn't growing well, he recommends planting shade-tolerant ground covers such as liriope or mondo grass, or simply covering the extended bed with a mulch such as bark or pine straw or a mulch that is popular in the region of the country where you live.
Competition from tree roots
Grass may also perform poorly in sections of the lawn close to trees, hedges and large shrubs. This time the issue isn't the canopy but the roots. The problem for grass that isn't growing well in these situations is that the roots out-compete the grass for water and nutrients, resulting in weak and spotty turf. "It's not always trees," says Waltz. "I've seen some large shrubs cause some of the same things."
He uses osmanthus as an example. "A big hedge of osmanthus will smell great, but those things get up to 8, 10, 12 feet tall, and they're blocking the sun and preventing air movement. Their roots, just like with trees, will out-compete the grass for light, water, space and nutrients. The water and nutrient part of it can be an issue because they will compete more aggressively for water and nutrients than the turf."
Again, as with grass trying to grow in too much shade, he said the grass becomes a stressed plant in a poor environment, and it can't get the basic elements of life when it has to compete with the large roots of bigger plants. "It's going to struggle and it's never going to do well." The solution, as with shade, is to expand bed line to at least the drip line of the tree or shrub.
One of the most under-appreciated reasons grass isn't growing well is compacted soil. This is a problem because plant roots need to breathe, and they can't do that in compacted soil.
"My analogy on that is how many hours a day do you like to breathe oxygen?" asked Waltz. "The answer is 24. Roots are no different." In compacted soil, oxygen's ability to move through pores within the soil down to the roots is severely limited.
Several things can cause soil to become compacted. One is that the site for the lawn was not properly prepared — tilled with organic matter added to the soil — before grass seed was sown or turf was laid.
This is common in many new housing developments, said Waltz. "The builder has spent money on everything else and is probably somewhat over budget. The last thing he is going to do is pay for somebody to come in there and deep till the lawn or landscape and break it up 6 or 8 inches deep and soften it up in the upper 3 to 4 inches before ever putting sod down. I can say I almost never see that happen. More often than not, they scrape off the area where they are going to install the lawn, they get it somewhat smooth on top, they might run a tiller over it and say it was tilled and then they lay sod with the green side up."
When this is the case, the compacted soil limits oxygen to the roots. "And when you start limiting the oxygen down to the roots, the roots grow near the soil surface to get what oxygen they can.With shallow roots, the grass is more susceptible to environmental stresses like heat and drought.The deeper roots can grow, the more soil volume the grass can use to extract water and nutrients, helping the plant make it through stress periods."
Notably, Waltz said there's a lot of information on the ornamental side about how to dig a hole to plant a tree or shrub, but seldom does anyone emphasize soil preparation prior to installing grass. "Most landscape architects have details or specifications for planting trees," he pointed out. "Short of a constructed root zone, I'm not sure I've ever seen a 'detail' on a set of plans for preparing soil for sodding or seeding."
Another reason soil becomes compacted can be because of the same small tree the contractor planted that eventually matures and casts shade across the landscape. "Ten or 15 years down the road when that tree is walking its roots across the surface of the soil, you can't grow grass on it anymore, and the homeowner is wondering why," said Waltz.
"When you wind up having exposed tree roots, many times that can give you an indication that you have some compacted soil. Because if those tree roots could go down, they would go down. They wouldn't crawl across the top of the soil. As tree roots kind of start to mature and get bigger, you have the same amount of soil there, so those roots are occupying volume and space so they are compressing that soil as well. So, the tree roots can add to some compaction issues. So, if the soil wasn't prepared well, then with time and the increased number of roots right there at the surface, many times compaction will go up as well."
If you have compacted soil, Waltz recommends core aeration to open the soil to allow oxygen to get down to the root system. Core aeration is typically performed with a powered machine that has a drum with hollow tines that pull plugs of soil out of the lawn. The plugs lay on the surface and look unsightly for a short time, but will dissolve back into the lawn with rain and when you run your sprinkler.
Even aerating 3 and 4 inches deep can make all the difference in spots, said Waltz, pointing out that many lawns need aerating annually on a continuing basis. "If you have a significant compaction issue, the lawn may need to be core aerated a couple of times a year. This may be a two- to three-year process. After that, you may just need to core aerate every second or third year. Core aeration opens the soil and introduces oxygen into the soil system, benefiting the grass, the trees and soil microorganisms."
Sometimes, homeowners might notice that some sections of the lawn appear particularly stressed during weather extremes such as drought and prolonged high temperatures. In this case, you may not only have to look down but underneath, as in underneath the soil, to find the problem. It's possible an underground object is preventing deep root growth and limiting the ability of roots in that area to reach a soil reservoir from which they can pull water and nutrients to keep the grass in that area strong and vibrant.
"There have been times where I have taken my soil probe into some areas and hit granite at about 3 or 4 inches," said Waltz. "You tend to see that become a problem when there are stress problems — when it's hot, when it's dry and when the grass doesn't have as deep a root system."
Through the years, he has seen all kinds of issues with underground objects. "I've even found buried construction debris, although that's supposed to be illegal. I can't tell you how many times I have pulled the probe back up and found a piece of shingle on it just 1, 2 or 3 inches deep into the soil. And all the time the homeowner has been wondering why this area is the one that seems to wilt out and die every year! If you do enough probing, you'll start to find out why."
Sometimes with probing Waltz discovers that the problem is just hard clay. "The clay just isn't worked up, and you have a restricted clay layer where 2, 3 or 4 inches down that the volume of soil that the roots have to pull water and nutrients from is compromised. Those tend to show themselves during extreme stress periods."
Unfortunately, there isn't an inexpensive or easy fix for homeowners to find themselves in this situation. Short of digging up the lawn and starting over, core aerification may be the only solution, said Waltz. Even this can be a problem, though, if you have what he calls shallow soils where there are one or more large rocks near the surface. Sometimes, he said, the homeowner has to face the reality of "it is what it is” and manage what they have.
Lack of air flow
The final problem Waltz encounters most frequently is a small backyard around which Leyland cypress has been planted as a privacy screen. The cypress solves one problem — neighbors being able to look into your yard and vice versa — but it also creates another, a restricted airflow that results in stagnant air because there's little-to-no air exchange.
"You know how it is in your house when the fan doesn't go on with your air conditioner?" asked Waltz. "The air in the house gets kind of stuffy and stagnant. It's the same thing with a closed-in backyard, especially if you've got a little humidity mixed in. The air just gets stale and kind of stagnant," he explained, pointing out that the lack of air flow increases the likelihood the grass will develop disease issues. "You've got a weak plant (grass) and when you compound that with lack of air movement and air drainage, you run the risk of much-higher disease incidence. Sick plants don't live real well!"
Once again, correcting this situation can be a challenge since the plants that are causing the problem were planted for a purpose, such as to provide a privacy screen. Solutions, said Waltz, may include using something other than grass in the turf area or limbing-up trees and shrubs to promote greater air flow. Homeowners can also do what golf courses sometimes do to create airflow around putting greens, which is to install fans — though he quickly admits this isn't an inexpensive solution.
Over-correcting is often not the answer
Some homeowners may think that they can add more fertilizer or aerate more often to correct problems where grass isn't growing well. Waltz cautions against that.
The real problem, he contends, is that you have the wrong plant in the wrong place. Therefore, increasing the amount of input to try and get grass to perform in these situations, especially in shady locations, will result in, at best, weak and tender new growth that's susceptible to disease and pests. Disease is difficult to control in these situations because the environment is so conducive to disease. You're also likely to find yourself spending more on pest control.
His preference, he said, is to always help folks grow grass sustainably so they're not always having to dump what he considers above-and-beyond resources back into the landscape. That's just not the way he believes that grass should be managed.
"So, you have to be real careful there," Waltz advised. Again, ask yourself: Is what I am doing sustainable? Therein is the paradox of the wrong plant in wrong place. "So, is increasing inputs really the sustainable solution?" he asks. "Many times, I would say it is not."
What about HOAs that require grass?
Waltz said that through the years he's gotten pleas for help from desperate homeowners who tell him they can't grow grass, and now their HOA is threatening to fine them because their lawn looks so bad. When that happens, he makes a site visit to determine what's going on with the homeowner's lawn. On occasions, his assessment has been that the site isn't suitable for turf for one of the five reasons above.
When that's the case, he steps up and says growing grass here just isn't going to work. When he finds himself in these situations, he has "to be an advocate for the plant and that includes not setting the plant up to fail." After all, he points out, plants aren't going to advocate for themselves.
"I go back to a little bit of terminology and try to articulate the real issue," he said, adding that he does this in emails and letters to HOAs. He said he's been very honest in his correspondence and told the HOA that, "You are asking this individual to do something that is agronomically unsound and possibly environmentally irresponsible."
I've recommended to a couple of them that either they throw away their covenants or go back and re-write them so they stipulate requirements that are more agronomically and environmentally sound. "What I have found is that many times this tends to be enough. I haven't gotten a whole lot of blowback off that."
Waltz has had some other firsthand experiences with HOAs that have made unreasonable requests. "One HOA in north Atlanta called me one time and wanted me to bless a list of native grasses because they were going to make all of their homeowners put in native grasses. One of those was buffalo grass. I said, 'I'm not going to do it.' They asked why. I said, 'You are setting yourself up for failure.' They asked if buffalo grass wasn't a native. I said, 'Yeah, but not here in Georgia. It's native to North Texas and Oklahoma and Kansas. Buffalo grass will fail here.' They didn't want Bermuda grass because they said it's on the invasive plant list. I said, 'Well, that's your decision to make, but as much open space and sun as you have, that is going to be your most sustainable species.' I don't know whatever became of that ..."
For anyone who has Bermuda grass, Waltz said not to worry about its reputation as an invasive plant. "Bermuda grass has been here long enough to have gotten its citizenship," he said. Without Bermuda grass, besides for turf purposes, we'd have a hard time feeding cows, goats and horses, so be thankful it's somewhat "invasive"!
Where to go for help?
"If you have a problem growing grass, I would start with your county extension office and county extension agent," Waltz said. "Some will come to your home to evaluate your situation. In urban areas where a county has a million people, it may be difficult. So, obviously, they can't make all the home visits they would like."
He thinks that's a better option than going to a lawn care professional as the first option. Landscape designers, contractors and practitioners would understand the problem, he said, but their use of terminology isn't always spot-on. "They are in the target, but many times they are on the outer rings of the bullseye to articulate exactly what is happening."
Extension agents, on the other hand, are specialists in assessing turf problems and resolutions. Even if the agent can't come out, he or she may be able to send a master gardener instead.
"Many offices will use master gardener volunteers," Waltz said. "The volunteers have to apply and then be accepted into master gardener program. After that, they have to go through a really extensive year-long course to maintain their master gardener status and then they have to give back volunteer hours on an annual basis. Sometimes those volunteer hours are a matter of helping the county agent out."
The master gardener would assess the site and they can report back to the county agent. They might also send out a local professional they are comfortable with. Regardless, Waltz advised, "This is where I would start" if I was someone who is having a hard time getting grass to grow.