Peak time for lawn work
The passing of Labor Day opens the best window of the year for lawn work. September and October are peak months both for starting new lawns and rehabbing sad ones.
The soil is still plenty warm enough for good grass-seed germination, while the cooling temperatures and (ideally) more regular rain make for good growing conditions for those young grass roots.
If you’re starting from scratch, you have two options.
One is to clear and loosen the existing soil, then tamp grass seed into the surface.
The other is laying sod, which is carpet-like sections of already-growing grass that garden centers sell – roots and all. This option gives you an instant, mature lawn but is much more expensive.
Here’s how to seed a new lawn:
1.) Prepare the soil by removing all vegetation and loosening to a depth of four to six inches. Rent a tiller unless you’re seeding a small area that can be dug by hand.
2.) Add an inch of organic material, such as compost, mushroom soil, or peat moss, and incorporate it thoroughly into the existing loosened soil. If your soil already is good, skip this step.
3.) Rake the soil smooth, and scatter grass seed over the surface at about the density you’d salt a steak. Seed doesn’t need to be so dense that it touches, but you’ll need more than just a few seeds per square foot.
4.) Lightly rake in the seed so that some is a quarter-inch deep and some remains on the surface. Lightly tamp, and cover with a thin layer of straw or a lightweight, spun-bonded polyester garden fabric (also called “floating row cover”) to discourage birds, retain soil moisture, and help prevent erosion from heavy rain.
- Watch George’s video on floating row covers
5.) Water enough to wet the soil about two inches deep, then keep the soil surface consistently damp with frequent light waterings until the seed sprouts. Figure on daily waterings and maybe even twice a day if it’s hot and dry.
6.) Remove the fabric once the seed is up, and cut back on the watering to every two or three days. If you used straw, that can be left in place, unless it’s matting down the new grass. Wait until the grass is three inches tall to mow for the first time.
To start a new lawn with sod, do the same first two soil-preparation steps as with seeding, then:
1.) Buy, unroll, and lay strips of sod, butting them up against each other and in a staggered pattern, similar to how bricks are overlapped.
2.) Fill in any gaps with cut pieces, and fill small cracks with topsoil. Tamp down the laid pieces or go over larger areas with a roller.
3.) Water well so that both the sod and the top two inches of soil are damp. Keep the planting damp – with daily watering, if necessary – for the first four to six weeks.
To thicken a thin lawn, the process is similar to seeding a new lawn, except that you’re not clearing and loosening the entire area.
However, scratching or roughing the soil surface is very important because seed will germinate best when it’s either tamped into the surface or incorporated into the top quarter-inch of soil.
You won’t get very good results by just tossing seed on top of the hard ground.
To overseed a thin lawn:
1.) Mow the grass shorter than usual, to about one or two inches. Rake up any debris.
2.) Loosen or at least scratch the surface of bare areas that will get seed. Or plan on overseeding after you aerate or dethatch the lawn or otherwise disturb the soil surface.
3.) Scatter seed over the bare or thin areas, lightly rake, and lightly tamp to achieve good seed-to-soil contact. Covering with a light layer of straw is optional… more useful in larger and thinner areas than where the grass is just a little thin.
4.) Water the same as above after seeding a new lawn.
A seeding alternative for large areas is renting a “slit-seeder” or seeding machine. This power equipment has vertical blades that cut shallow slits in the soil. It then inserts seed from hoppers behind the slits.
- Watch George’s video on how to fix a ratty lawn
What kind of seed?
Grass might seem like grass, but it’s a plant that comes in many varieties – each suited to a different situation.
The performance of a lawn depends much more on the variety planted than most people realize.
Choose poorly, and you could set yourself up for way more trouble with bugs, disease, drought, and dead patches than if you had picked a good variety in the first place.
Three types of grass make up most Pennsylvania lawns: Kentucky bluegrass, perennial ryegrass, and fine fescues.
A fourth type – turf-type tall fescue – is another choice that’s especially good at tolerating foot traffic, although it often looks a little coarser than the above three.
Under each of those types, particular varieties are available that deliver supposed improvements in different growing aspects. Universities spend a lot of time trialing these new and different varieties to determine which ones really are better.
Golf courses, public park systems, sports-field greenskeepers, and other large-use planters pay way more attention to variety differences than homeowners, who are usually attracted to whichever bag is the cheapest.
Since homeowners shop on price, most retailers tend to carry cheap varieties instead of the best-performing varieties.
What’s more, pay attention to how much seed is actually in a bag if you’re retail shopping. Many if not most retail seed now comes with mulch and/or seed coatings that can account for half or more of the material in the bag. Read the label to see what percentage of the material is seed.
If you care about planting the best – or at least better – varieties, you can see each state’s variety-trial results on the National Turfgrass Evaluation Program website.
Select the State Data button, then hit Pennsylvania on the map to see results from Penn State University’s trials. Then start reading labels and/or searching online for varieties that catch your eye.
For seeding a new lawn, Penn State’s Center for Turfgrass Science recommends one of these mixes:
For a sunny, open area: Use either all Kentucky bluegrass or all turf-type tall fescue. Or use a mix that’s 80 percent Kentucky bluegrass and 20 percent perennial ryegrass, or a mix that’s 40 to 60 percent Kentucky bluegrass, 30 to 40 percent fine fescue and 10 to 20 percent perennial ryegrass.
For a partly shaded area: Use a mix of 40 to 50 percent Kentucky bluegrass, 40 to 50 percent fine fescue, and 10 to 20 percent perennial ryegrass.
For a shady area: Use all fine fescues.
For a sunny area that gets a lot of foot traffic: Use all turf-type tall fescue or a mix of 80 to 90 percent Kentucky bluegrass and 10 to 20 percent perennial ryegrass.
Adding superior seed varieties each autumn or two gradually improves your lawn quality as the older grasses age and die out.
Black-eyed susan disease
Lots of gardeners have been reporting troubles the last couple of years with their black-eyed susans – long a reliable summer-blooming perennial. The plants are turning black and dying back to the ground.
The problem most likely is a fungal disease that thrives in wet or humid summers – Septoria leaf spot.
Septoria causes black spots on the leaves that multiply and coalesce until most of the foliage is black and dead.
Fungicides can keep a lid on the problem, but the key is getting the sprays on at the onset of the disease and keeping the leaves treated as long as the weather is ripe for fungal growth.
After the damage is done, it’s too late. The time to spray (if you’re a spray-prone gardener) is at the first sign of spotting on the lower or inner leaves.
Plant pathologists recommend weekly sprays to prevent the disease from getting a foothold. Chlorothalonil (Daconil) is a common fungicide that’s effective. Organic gardeners can use copper-based fungicides.
The good news is that there’s a very good chance infected plants will regrow the following spring.
A few things help discourage a repeat of the disease.
One is raking and removing dead foliage, since that’s a source of spores to keep the disease active.
Another is dividing and spacing out the plants to 18 to 24 inches apart. Crowded plantings trap moisture on the leaves that encourages the disease. Airing them out helps the leaves dry better.
A third option – if this becomes an annual problem – is replacing the disease-plagued black-eyed susans either with more disease-resistant varieties of them or with altogether different species, such as mums, coneflowers, coreopsis, daylilies, or salvia.
The popular ‘Goldsturm’ variety of black-eyed susan (which most gardeners have) apparently is very susceptible to leaf-spot diseases. The new ‘American Gold Rush’ variety is one high-performing, heavy-blooming variety that’s also more disease-resistant.
- More when-to-do-what tips: George’s “Pennsylvania Month-by-Month Gardening” book