How to “Read the Weeds” for a Healthier Lawn
Problem plants are a symptom, not a disease — listen and they will help you understand your soil’s needs.Posted May 29, 2014
“Weeds” are plants out of place. Each of these species have their own niche in their native ecosystem, but when introduced to disturbed soil around human habitation, can flourish out of control…
They boldly claim space and nutrients intended for our chosen ornamentals or edibles. Some were deliberately imported, but spread far beyond the control of their propagators. Other weeds provided essential nutrients and healing remedies to our hunter/gatherer ancestors (modern foragers are rediscovering wild edibles — even the dreaded invasive Japanese Knotweed can make a tasty pie!).
Dangerous and costly landscaping services are marketed to concerned homeowners who are confused about how to make their lawn resemble an idyllic manicured golf course. Fortunately there are alternatives! Your weeds are trying to tell you something. Once you learn a little of their language, these misunderstood plants can often provide the information you need to adjust your soil health and cultivation techniques naturally.
When assessing your lawn or garden area, just scan for the dominant weeds, and overlook the occasional volunteer. If you don’t know their names, . There are several basic problem areas to look for: pH imbalance (too acidic or too alkaline), fertility imbalance (too rich or too poor), soil compaction or crusting, and moisture imbalance (too wet or too dry). Here are several common weeds and a rough translation of their message to you.
An opportunist, crabgrass often shows up in newly planted lawns where fertility is high and space is available. Both drought and sogginess can give crabgrass an advantage over lawn turf. Make sure you’re not mowing too low: crabgrass can often be controlled by keeping the surrounding grass higher. It’s an annual, so preventing seed-spreading is key. Corn gluten can be used on established lawns to discourage germination.
Every toddler’s favorite flower, the perennial dandelion is now well known as a nutritious edible spring green. A few dandelions can be pretty, but if you find they are taking over your yard, you may have a calcium deficiency or an excess of potassium. Dandelions also thrive in compacted soil. They can actually help loosen earth with their long taproot, and bring up calcium from deep down to share with other plants! If you mow your grass long (3+ inches) to shade the leaves, and correct your soil’s imbalances and texture (consider renting an aerator if compaction is the problem), the mature dandelions will weaken and your vigorous grass will out compete any new seedlings.
This tuft-like grass produces abundant seed even when mowed closely. It grows well in shady spots but needs lots of moisture. Causes include low mowing height and over-frequent watering (this also applies to bentgrasses, another seedy tufted invader). Generally an indicator of high fertility, annual bluegrass prevalence is sometimes corrected by aerating, as it grows well in poorly-drained ground where conventional grass struggles.
Often mistakenly referred to as “yellow clover”, black medic means nitrogen deficiency and general poor fertility. Unchecked, this plant will lay foot-wide flat mats of spreading tendrils. Top dressing your lawn with compost or an organic fertilizer should reduce black medic to a harmless visitor.
Prostrate knotweed gets its advantage from early germination, claiming space and gobbling up resources before neighboring plants have even awoken. Any bare spots will be vulnerable to this low, tendrily plant which can mimic grass upon first emergence. Look for hard, compacted soil or high acidity where you find prostrate knotweed.
A tasty addition to spring salads, chickweed thrives in fertile, well-watered conditions. Chickweed overgrowth may be a sign that your lawn is poorly drained, over-watered, or your soil is overly dense and compacted. Aeration helps. Always wait between waterings until your lawn shows visible signs of drought stress, and then water deeply.
These tough little plants dig their taproots where nothing else can grow: driveways, sidewalks, footpaths. With lots of traditional healing uses, it’s handy to have a few plantain leaves growing near to apply to a wasp or nettle sting; children are soothed by the ritual of chewing the leaf to make a poultice. If the plantains in your lawn are outperforming the grass, fertility is low and density or compaction may be high. Try the screwdriver test to see if aeration is needed: if you can’t easily plunge a screwdriver up to the handle into your lawn, it’s too dense. Look into significant compost mulching, and mow high to shade plantain. High acidity is also likely.
Also called sheep sorrel, this weed is an indicator of acidic conditions, and will quickly colonize disturbed soil even very low in nutrients: thick colonies of red sorrel are found in depleted sites like abandoned mines. If you improve your soil’s fertility and regulate over-acidity with lime, red sorrel should subside.
If you’re finding yourself gathering sweet little bunches of violets more often than you’d wish, it will probably come as no surprise that your lawn is shady and wet. Drainage can be improved, but shade is often not correctable. With shaded lawns, it’s especially important to avoid mowing too low, as the grass takes longer to recover. Make sure you’re using a grass well-suited to your site: fine fescues will compete better in this situation than Kentucky bluegrass.
This leafy perennial is hard to ignore, with big coarse leaves that sprout up fast and high if you miss a mowing or two. The flower stalk is a towering, prehistoric-looking brown spindle. Dock grows in acidic, wet conditions, and loves bare patches. Liming and improving drainage are long-term solutions; meanwhile, cut back often to prevent seed production. Seeds are viable up to 50 years! Existing plants will die after 3-5 years, so vigilant mowing is a good alternative to laborious digging of deep root systems.
Too many daisies of any variety indicates mild acidity, and Oxeye in particular is a sign of seasonal sogginess. Like all species who reproduce only by seed, the daisy is dependent on available space for germination. Conditions leading to bare patches or insufficient density of grass provides an opportunity for daisies to multiply. Correct poor fertility, and reseed if necessary with regionally appropriate grass seed to provide the necessary density to crowd out seed-borne weeds.
Too much clover? Your chlorine, magnesium, and sodium are all likely to be high. Over-enthusiastic clover is also a sign of nitrogen deficiency, but this helpful weed actually contributes nitrogen to your depleted soil! It also stays green in drought conditions longer than grass. For these reasons clover is often deliberately added to organic lawns, especially in areas where nitrogen-depletion is common. It developed the reputation of a weed because chemical herbicides kill clover, leaving unsightly bare patches. Increasing your lawn’s fertility with compost will give the grass a hand.
Traditionally used to heal cuts, Achilles was rumored to carry yarrow leaves into battle for staunching wounds. Potassium and moisture levels are probably low where yarrow is vigorous; this hardy sweet-scented perennial grows in poor, dry soil. In fact, in drought-ridden California, some are experimenting with deliberately planting a “yarrow-lawn” as a low-maintenance grass-alternative. If your area is experiencing prolonged drought, consider this or other xeriscaping alternatives to opt-out of the worsening stress of maintaining thirsty grass in a water shortage. Another promising option is drought-tolerant grass such as Eco-Lawn.
Earth-Friendly Lawn Care Tips
If your favorite (or least favorite) weed is not featured here, check the links below to find out more. Regardless of the specifics of your terrain, all lawns benefit from a few earth-friendly tips:
- Test your soil if you’d like more details about how to work with what you’ve got. A pH of 6.0-7.0 is ideal for lawns.
- While you wait for your grass to strengthen and compete with the weeds, consider hand-digging or topping weeds to avoid seed production, which can lengthen your struggle by years.
- Mow high, mow often: adjust your mower to leave at least 3 inches of grass. You’ll get healthier root systems, less thatch, and shade to weaken low weeds.
- Wait to water until your lawn looks thirsty: the color should dull and footprints should stay compressed for more than a few seconds. When you do water, put a cup in the sprinkler zone and wait for 1” of water to accumulate.
- If your lawn is too dense to sink a screwdriver, talk to your neighbors about renting an aerator together to save money.
- Corn gluten, applied to established lawns in early spring, wards off many weeds by preventing germination, while nourishing grass through moderate nitrogen gain. Avoid corn gluten when reseeding.
- To enhance your mowing experience and lower your lawn’s carbon footprint, switch to a reel mower.
- Once the soil and grass are healthy, try to develop a tolerance for the occasional weed volunteer. Remember, a blooming lawn attracts and supports beneficial insects like butterflies and bees. Without pollinators— widely threatened by pesticides, climate change, and habitat loss — human civilization in its current form would be unable to sustain itself. By avoiding poisonous weedkillers, you’re reducing the damage to pollinators, as well as people and pets.
Since an English engineer named Edward Beard Budding invented the lawn mower in 1830 (mechanizing a process that had previously been accomplished by grazing animals or servants with scythes), the cultivation and maintenance of our household lawns has become a national preoccupation. It’s the view out of our living room windows, a soft place for our children to romp, a carpet for our summer barbecues and a backdrop for our personal ideas of domestic beauty. Though more and more Americans are feeling the pressures of climate change and rethinking the lawn’s primacy, for many of us the lawn remains central to our daily routines. Luckily, in most climates there are sustainable ways to keep and maintain this treasured play-space.
In lawn-care as in life, we strive to strike a balance. The healthier your soil, the more naturally luxurious your lawn will become. Listen to your lawn, approaching each weed in a spirit of curiosity and collaboration. The pay-off: less toxic chemicals, greater understanding of your ecosystem, and less yard work in the long run.