Good Soil and the Right Type of Grass

Lawn care companies would likely blame the damage to the lawn above on chinch bugs and offer to poison them for you, but the real solution is to address the underlying causes: poor soil and the wrong choice of grass! Photo: http://www.growinglawns.com

When I hear people complain that their lawn is full of weeds, turns yellow, suffers from dead patches, is infested with insects and diseases, etc., I know right away what is really wrong. Someone decided, perhaps ages ago, to save cash by installing sod without taking a crucial step: putting down a good layer of quality top soil first.

I’m not necessarily blaming the current owner. You may have bought your home second-hand. And even if it’s a new residence, it may well have been the builder who installed the turf and, as is so often the case, decided to cut corners by laying sod directly on crappy landfill or subsoil.

And what a mess a lawn becomes when it planted on poor soil! Of all the things you grow, only vegetables depend more on good soil than a lawn. Yet, at first, the problem is not too obvious. Sod comes with a very thin layer of really good soil and covers a lot of defects. As the result, at first the lawn may seem to be doing fine, even if it was placed directly on hardpan clay, sand or construction waste. 

But in most temperate climates (and, sorry for you Southerners, but this article is based on a “cool season lawn”: the type of lawn used climates with cold winters and hot summers), the only lawn grass sold as rolls of turf is Kentucky bluegrass (Poa pratensis) and it’s the most demanding of all the lawn grasses. A freshly sodded bluegrass lawn will often live on its reserves for a year or two, maybe three, actually looking quite nice and giving the impression that the installation was successful, but begins to fall apart after that. And when it weakens, weeds, insects and diseases move right in.

The First Key to Success: Good Soil

You simply cannot grow a decent lawn on poor quality soil. It takes at least a 6-inch (15 cm) layer of top-quality soil (8 inches/20 cm is even better!). Ideally, this would be a soil mix especially designed for lawns, structurally more stable than, for example, a blend designed for vegetable gardens, as it has to put up with foot traffic. And it should be free of weed seeds.

With good soil at its base, you’ll have a much better chance of keeping your lawn in excellent condition!

The advice above is great if you are putting in a brand new lawn, but what if it’s too late and your lawn is already in poor condition?

Revamping a Badly Damaged Lawn

If your grass is really in bad shape, with over half the lawn dead, the most logical thing to do is start over. Remove the old lawn (consider renting a motorized sod cutter), cover the now-bare space with 6 inches (15 cm) of quality lawn soil and install new grass, but—here’s the clincher! —, not just any grass.

The Second Key to Success: Low Maintenance Grass

Yes, the second key to success in having a beautiful lawn is to install not a classic cool-season lawn composed only of Kentucky bluegrass, but a low maintenance lawn (also called an eco-lawn).

This kind of lawn contains several grass species. Yes, there is probably some Kentucky bluegrass included, but if so, only selections especially resistant to tough conditions. Above all, though, these lawn mixtures contain other grasses, in particular various fescues and perennial ryegrasses, which are specially chosen to tolerate abuse and which are notably more drought resistant than most bluegrasses. In addition, the varieties chosen require less mowing and much less fertilizer than conventional turf… and no poisonous fungicides and insecticides.

But the biggest advantage of low-maintenance lawns is that the majority of the grasses used contain endophytes, that is, beneficial fungi, and they’re found in all green parts of the plant (although not in their roots).

You cannot “add” endophytes to an existing lawn in the same way you can add mycorrhizae (another type of beneficial fungus). Endophyte means “within the leaf”. Endophytic fungi live in symbiosis with grasses, but inside their tissues. And when these grasses produce seeds, the endophytes are present in those seeds and are thus carried to the next generation.

Why are endophytes so valuable? Because they help the grasses that contain them better resist weeds, survive extreme heat and recover faster after a drought. Most importantly, though, they make the green parts of the plant toxic to defoliating insects, which greatly reduces or even eliminates predation, especially from chinch bugs and sod webworms. Apparently, they even reduce predation from white grubs, although it’s not fully understood why. Therefore, the presence of endophytic grasses in a lawn is highly desirable and seriously reduces maintenance.

Kentucky bluegrass never contains endophytes (it simply doesn’t host them), but many varieties of fescue and perennial ryegrass do. And it is these varieties that are incorporated into low maintenance seed blends.

Also, low maintenance grass seed often also contains white clover seeds (if not, it can be added during seeding). Clover is always useful to a lawn because it provides nitrogen to the grasses and stays green even in the worst droughts.

When to Sow Lawn Seed?

The best time of year to redo a dying lawn or start a new one is in late summer or early fall, from late August to mid-October, depending on your climate. It can also be carried out in the spring.

Where to Find Low Maintenance Grass?

Usually, low maintenance lawns are mostly available as seed. You now can find low maintenance seed mixes in most garden centers. If not, try on-line sources. Two brands with an excellent reputation are Eco-Lawn and Pearl’s. Yes, they cost more than the lowest quality Kentucky bluegrass seed, but it’s an investment that pays for itself.

A few sod growers now offer ready-to-install low-maintenance sod. It remains a fairly rare product, but check with local sod producers. You’ll probably have to place a special order to obtain it. The sod inevitably offered in garden centers is still entirely composed of bluegrass and not even quality bluegrass at that. (Quality varieties are usually saved for golf courses!)

Do remember that even low maintenance grasses, whether from sod or seed, still require that 6 inches (15 cm) of quality soil to do well.

How to Fix a Weak Lawn

Not all lawns require a total reboot. If your lawn is “not that bad”, but could be better, it’s possible to convert it to better quality sod. 

Start by topdressing the lawn, that is, covering it with about 3/4 inch (2 cm) of lawn soil or compost, then overseed that with low maintenance grass seed. Again, late summer/early fall is the best season for makeovers. It would probably take a second top dressing/overseeding combination treatment the following year to really bring your lawn up to par.

In the future, maybe every 4 or 5 years, if you see your lawn’s quality starting to decline, repeat the same treatment: topdressing with quality soil or compost followed by overseeding with low maintenance grasses. That way, your lawn will always be beautiful!

Good luck with your properly restored lawn!