Lawn Rehab (Decisions)
Planning a Lawn
If you don’t have a thick, lush lawn to begin with, nothing’s more frustrating than hearing about how the best defense against weeds or lawn pests is a healthy lawn. How do you convert a crappy, scrappy, weed-infested yard into a nice, thick, self-sustaining lawn?
First — and you probably don’t want to hear this — cultivate patience. Rebuilding a damaged lawn takes about two years, so figure on investing a fair amount of energy on planning in the early days. There are three steps to this process: finding out what you’ve got, figuring out what you want, and then planning how to get from the one to the other. The first two steps can be done in either order, as it really doesn’t matter whether you explore your imagination or your yard first; that’s a matter of temperament, and I’m not ready to take a stand on which is superior. Sometimes it helps to start with the purely imaginary, before you’re brought back to earth by reality. However, your ideas about what you want will probably grow and change with time, so keep those initial lists handy for updating. If you do start by assessing, don’t let what’s actually there keep you from seeing what could be.
While you’re in the planning process, cast a wide net. The library and the internet can help you, but landscapers, bookstores, nurseries, neighbors, and local organizations can be great resources as well.
Think big — or perhaps small. For too many of us, the lawn becomes a box. Think outside it. Some areas may need something other than grass. Grass loves sun, so if you have shaded areas you may want to put another form of ground cover there. Several options require less water and no mowing — always a plus. See Grass Alternatives for more on these.
If you like to barbecue, it may make sense to have a special outdoor cooking area that features brick, gravel, or something else that is fire resistant and can handle plenty of foot traffic. Not only will it be more functional, it may look better, too. Trees can be encircled with rock gardens, native plants, or even gravel, any of which reduces the amount of grass in heavily shaded areas. These ground covers will also make mowing easier and protect trees from the occasional nicks that can allow disease to take hold.
Don’t stop at finding the best grass seed for your neck of the woods; think also about adding rock, meadow or ornamental grasses, shrubs, and garden beds. When it comes to the lawn, less can be more (see Less Lawn More Life).
Even thinking about thinking about all this can be exhausting, but it’s probably worth tackling. After all, why renovate lawn in areas where in fact you’d rather be growing something else?
The Wish List: The Golden Future
What do you want your lawn and garden to look like? How perfect does the grass have to be to keep you happy? Do you care whether you have several kinds of grass in your yard? Do you care whether you have broad or fine-bladed grass? What’s your weed tolerance? If you can’t see them and they’re not going to take over, do they bother you?
Answers to these questions will help you determine your lawn needs.
Within the space you’ve got available, how big a lawn do you want? This question overlaps with, Use, of course, because crochet and volleyball, for example, require a fair amount of space, while if you just want vistas of the distant mountains and a path to reach the garage, you may not need much lawn at all.
How much time do you want to spend on your lawn? Is it one of your pet projects, or is it the step-sister to the garden, which you love?
What kind of use does your lawn get? If kids are playing soccer on it, you’ll need a tough, resilient grass. If it’s where you set your lawn chair to read, almost anything will do.
Assessment: The Leaden Present
Map What You’ve Got.
Start by mapping your current yard. Distances don’t need to be precise, so “sketch” might be a better term, except that there’s no need here for artistry. Note what plants are located where, and sketch in existing structures, trees, shrubs and grass. Also, figure out how much sun different sections of your yard gets. What parts are in shade for most of the day? In direct sun? Such differences affect moisture retention as well as light level, and these factors can affect planting choices.
The Smart Yard: 60-Minute Lawn Care (by Jeff Ball and Liz Ball) devotes a chapter to assessment. See this book for great tips on how to figure out how compacted your soil is, how healthy your grass is, and so on.
The Overview: Space, Time, Appearance, and Uses.
Pretend you’re a stranger, and look at your lawn. How does it look, over all? Don’t be your own worst enemy here, just be honest.
How big is the lawn? Knowing the square footage of your yard not only makes it easy to calculate seed and fertilizer needs, but it also protects you from awkward social situations, such as this sort of exchange at the seed counter:
Clerk: How much do you need?
You: Uh– Uh–
Clerk: Well, how big is your lawn?
Its best to get out there with a tape measure and do the math.
How much time do you spend caring for your lawn and how do you spend it? How often do you mow? Fertilize? Aerate? Do you rake up the grass after mowing? What do you do with it? Do you rake leaves? What happens to them?
Grass is Grass, Right?
Type(s). What kind or kinds of grass have you got? You might know the answer, but if you don’t (and that would make you like most of us) you’ve got several options. You can hire an expert to come tell you what’s what (be sure to take notes!), or you can pull up representative samples and drop in at your county extension office, where you’ll probably have to pay a small fee, or you can do the job yourself.
If you go for the third, I recommend using one of the grass identification sites listed in Sites & Sources, under Identifying and Choosing a Grass. Most use branching algorithms, so you make a basic choice between two possibilities, which takes you to another page, where you make another choice. If you don’t have a laptop, or a perfect memory, you’ll do a lot of running inside and out unless you pull a sprig (with a bit of root) and take it with you to wherever you’ll be doing the job.
Density. If you can see patches of dirt between the clumps of grass in your yard, you have a problem. Those patches are weed-magnets, and if you don’t fill them with grass, then nature will fill them for you — and probably not with grass.
Thatch. If instead of seeing dirt, you see a matted layer of roots and dead stuff, you’re looking at thatch. It’s a good thing as long as it’s only about a quarter to half an inch thick, as it helps slow evaporation from the ground, provides organic matter to the soil, protects both soil and roots from summer’s heat, and to some extent slows seed germination, thus providing a minor barrier against weeds.
When thatch accumulates to more than half an inch in depth, though, it can cause problems. It may start choking out the grass, and it may prevent light rain or watering from reaching the soil where it’s needed. So, how deep is your thatch? Measure.
Root Depth. Shallow roots cannot reach as many nutrients as can deep ones and cannot reach water for as long after a rainfall. With a sharp, narrow trowel, dig out a “core sample” from your lawn — a grass plug about six inches deep — and look at the root depth. Roots should extend through all six inches of the core. If they don’t, your grass is not as healthy as it could be.
Weeds. First of all, approximately what percent of your lawn is weeds? Experts generally agree that if you’ve got over 50% weeds, fighting them is fighting a losing battle. In this case it’s probably time to kill it off, either the whole thing or one section at a time, and either all at once or over time. What option you choose will depend on what weeds you’ve got, how much of a hurry you’re in, and a number of other factors. There’s a section on all this here: the 50% solution.
If your lawn is under the 50% mark, then how many weeds does it have, and what sorts? Is your main problem the occasional dandelion? If it’s clover, consider that until the 1950s most grass-seed mixes included clover, which has pretty flowers, stays green all summer, and adds nitrogen to the soil, where grass can use it (see Establishing Clover in Lawns). However, it also attracts bees, which is reason enough for some people not to want it around, especially if you have kids.
If you don’t know what you’re looking at, try to identify it using whatever resources come to hand, (friends, neighbors, the many plant ID sites on the web) or dig out a sample and take it, alive, to your local county extension office where for a small fee you can let the experts figure it out. Do the weeds grow in dense patches, or are they interspersed in the grass? Different tactics are successful with these different situations.
There’s a more detailed discussion of soil itself in the page on Know Your Lawn; you can go there to get an idea of what precisely humus is, what pH stands for, and so on.
To improve your lawn, though, you need to know your soil’s texture, structure, and density; its pH, organic content, and mineral content; and finally its depth. You don’t need to know these with great precision (at least not all of them), but you need a ballpark estimate.
The first attributes (texture, structure and density) determine how easily and freely water and air move through the soil, while its pH and its organic and mineral contents reveal what nutrients the soil contains and how available they are to plants growing in it. Depth just tells you how much top-soil you’ve got, and whether it’s enough to support your grass.
Structure: does it crumble? Structure, which describes how soil particles (or peds) group or amalgamate, is a critical aspect of soil health, but tests for it generally carry Do Not Try This At Home labels, if only because they’re too complex. Fortunately, there is one exception. It’s best to perform this test a day or so after a rain (or watering), depending of course on temperature, shade and so on. The soil should not be either soaking wet or bone dry.
Remember all those movies in which the farmer squats down, picks up a handful of earth, and feels it? That’s our test.
Here’s what you do: Cut through the sod in an “average” part of your lawn, so you can get at the dirt beneath. You may not want to cut into your lawn, but it’s the only way to get an accurate reading of the soil underneath, as the garden dirt right next to it probably gets treated very differently. As soon as you lay the sod back, the cut will be almost invisible, and it should heal easily and swiftly.
Now we get to the highly technical part of this test: scoop up a handful of dirt and feel it. If you can’t scoop it up with your fingers, you already know something important about the soil: it’s compacted, and the structure is damaged. Use a trowel if necessary.
If the dirt runs loosely through your fingers, like sand, it has poor soil structure. Assuming it holds together, give it a little squeeze and wiggle your fingers as if you were trying to break it up with your thumb and fingers. That’s in fact exactly what you are trying to do — but don’t use a lot of pressure. You’re not trying to squeeze it together, you’re trying to break it apart — gently.
Soil with good structure will crumble in your hand (and out of it) when subjected to fairly mild pressure. It should not “dissolve” into tiny sand-sized particles, but break apart into many pieces of varying sizes.
If it doesn’t crumble, apply more pressure. Soil that crumbles at this stage probably has adequate if not stellar structure, but if you keep trying to crumble it and it keeps holding together, it probably has high clay content and poor structure. Try pinching a piece between your thumb and finger. If you can squash but not break it, it has very poor structure.
Texture: sand, clay, silt. In soil science, texture refers to the size of the ground-up rock particles in soil. Texture focuses on the mineral content, ignoring the organic material.
As with soil structure, you can get a feel, literally, for your soil texture by picking up a bit. Sandy soils will feel gritty and fall apart even when they’re damp, and you cannot roll out a sausage or ribbon of them, or even squeeze them into a coherent lump in your fist. Silt will feel powdery when dry, and will hold together somewhat if you squeeze a lump or roll it out. Clay can be so hard that a dry bit will be hard and sharp as a pebble. Wet, it feels slick or even slippery. Loam, at 20% clay, 40% silt, and 40% sand, is generally considered ideal for gardening.
To perform an easy, time-honored test for soil texture, you’ll need to dig about five inches of loose dirt from under your grass (and it’s important to dig, as what’s right on top may not resemble what’s three inches down) and put it in a quart-sized jar. Fill the jar with water, shake vigorously, and leave it overnight. The dirt will settle out in easily visible bands with sand on the bottom, silt above that, and clay on top (see How’s Your Soil Texture?).
If more than half is clay, you’ve got a very clayey soil. If more than three-quarters is sand, you’re looking at very sandy soil. In either case, you’ll need to amend your soil to improve its drainage.
Density: compaction. Packed earth impedes the movement of air, water, and roots themselves, and the grass suffers. There are several informal tests for compaction, but none suffices in itself, so be sure to use several. Compaction is so common that some parts of your yard probably have compacted earth unless you aerate and add organic matter regularly.
Here are several indicators of compacted soil:
• Rain runs off or puddles rather than soaking into lawn.
• It’s difficult to push a trowel or dandelion weeder into the ground when it’s dry.
• Grass roots extend less than three inches into top soil. (Check grass plug!)
• Even a good rainfall doesn’t soak into soil. (Dig to check. Soil should be damp 4 or 6 inches deep.)
• Topsoil is thin — less than 6 inches deep.
• Ice remains on lawn after snow has melted elsewhere.
A number of things can cause or contribute to soil compaction. Obviously, first among these is heavy use, which is why paths are almost always compacted. But a thin layer of topsoil, for instance, will compact more quickly and completely than a thick one, so building up your topsoil helps to relieve and prevent compaction. Clay soils, being composed of such minute mineral pieces, compacts more quickly than do sandy soils or soils containing plenty of organic material. Lawns that have not been recently aerated are likely to be compacted, as are those in recently built subdivisions where building and landscaping were done by machine. Finally, and this one may come as a surprise, walking on the lawn when it is frozen or snowy will lead to compaction.
pH. Soil pH, measured on a scale from 0 to 14, is a measure of soil acidity, with 7 being neutral. Low numbers indicate high acidity; high numbers indicate high alkalinity. Neither extreme is conducive to most plants, and a soil pH too far from that preferred by a particular plant means that it will not be able to gain access to the nutrients it needs. Grass prefers a slightly acidic soil, so a high pH would go a long way towards explaining an unhappy lawn.
You can buy kits to measure pH at home, or you can have it tested professionally, either by a university extension office, a county agricultural office, or a local nursery or landscaper. The home kits are relatively easy to use, but be sure to get a good one so that you can trust the results.
pH imbalances can be corrected with appropriate soil amendments.
Organic content: worms and humus. Good topsoil need only contain three to five per-cent organic matter, but that much is essential. Most U.S. lawns cannot boast so much, largely because most of us have been trained to rake up mown grass and fallen leaves, thus removing the only natural organic additions available.
One of the simplest (though not necessarily easiest!) ways to check for organic content is to do an earthworm count. Since earthworms eat humus, their presence indicates a reasonably high organic content. This test, which requires digging out a lot of dirt, should only be conducted when the soil is moist, for two reasons. First, digging in bone-dry dirt is really really difficult. (When the dirt is hard, the digging is harder.) Second, earthworms require moisture, so you won’t find any in dry earth. They’ll have moved out to more appealing quarters, deeper down or under a tree.
Start by removing a square foot of sod from your lawn; lay it aside in the shade while you work. Then dig straight down for seven to twelve inches, dumping the soil onto a tarp or square of plastic. (Seven inches will often bring you to the end of your topsoil; twelve will usually take you down into the subsoil, making it easier to measure the topsoil — see depth, below.) Sort through that soil, looking for earthworms. If you find at least five, you’re doing okay. If you don’t, you need to add compost, worm food. If you’ve got twenty-five worms or more, you soil qualifies as “rich.” Congratulations!
Mineral content. Thirteen fairly common minerals lead a double life as plant nutrients. In most cases, organic lawn-care practices including the use of compost and other soil amendments as needed should ensure that soil maintains an adequate supply of these. However, if your curiosity runs rampant, or your lawn seems not to flourish no matter what you throw on it, or you have reason to suspect some sort of mineral deficiency, you can test the mineral content of your dirt.
Some soil test kits available at gardening stores can test for the three primary nutrients needed by all plants, nitrogen (N), phosphorus (P), and potassium (K). Beyond that, though, you will need professional help. Your county extension office (again) will be able to put you in touch with soil analysis resources. An on-line search of that office should bring up a list of companies that do such analysis, detailing what precisely each one will test for and how much it costs. Twenty-five dollars or less can get you a measurement of the three primary nutrients, six of the others, plus analysis of pH, organic matter, salts, and lime.
Tip: The Rapitest Soil Tester (shown here) includes 5 color coded test tubes and a color comparison chart for testing nitrogen, phosphorous, potassium and pH (2 tests each – 10 total). Get instant results on the soil conditions in different parts of your garden or yard.
One note of caution: don’t grab a pinch of earth from the yard, throw it in a plastic bag and mail it off with a note asking for a soil analysis. A soil test requires a good deal more soil than that, and accuracy requires that it be gathered from here and there about the yard, so that results don’t get skewed by odd, local factors. (For instance, if you picked the one spot where the neighbor’s dog peed yesterday.) It’s necessary to contact the company, let them know what you want, and await instructions. They’ll send you a collection kit with detailed instructions.
Depth. It’s impossible to have a really healthy lawn unless you have enough topsoil, that rich top layer that’s the same to soil as cream is to milk. Just sticking a shovel into the ground can give you a good idea of how much you have, because there’s usually a clearly visible line dividing topsoil, which is dark, from the lighter subsoil. If you did the worm count mentioned above, check the sides of the hole. Eighteen inches of top soil or more is optimal but rare; you can get away with six to eight inches.
If you dug that hole, you probably noticed when the going got tough and you started hitting stones or cement-like clay. That’s subsoil — a different creature entirely and all very well in its place, but quite inferior as far as growing plants. Seriously, subsoil performs important functions in the structure of soil, but it’s not what you want near the top.
Adding a few inches of soil to a lawn that hasn’t been seeded is expensive but not impossible. Burying an existing lawn, however, makes no sense unless you never liked that lawn much anyway and you’re planning to re-seed entirely. (Just be aware that some hardy survivors from the old lawn will probably make it to the top of the new one.)
Building new topsoil on an old lawn requires a more gradual approach, a combination of aeration, top-dressing, and amending the soil. Aerating “fluffs up” the soil that’s already there. Top dressing adds to the layer. Amending the soil adds bulk as well, but it also improves the soil’s structure so that it’s better able to maintain its new, more porous state.