By Elaine Applebaum, UC Master Gardeners of Placer County
Q: I would like a lawn but am concerned about the environmental effects. Is it possible to have a beautiful green lawn without using chemical fertilizers and pesticides?
A: Taking a low- or no-chemical approach to lawn care is becoming increasingly desirable as people realize the dangers of non-point source pollution and exposure to children when they play on chemically treated lawns and athletic fields.
We tend to turn to chemicals to “fix” the problems we encounter in our yards. These problems arise when turf is stressed. Instead of going into reactive attack mode, we should be proactive and focus on the overall health of the grass. Healthy lawns can successfully fend off the stresses of disease, insect damage and weed infestation without chemical input.
If you are putting in a new lawn, autumn is the best time of year to do it. Proper location, turf selection and soil preparation are key to the success of any lawn. Most lawns require sun, good air circulation and good drainage to avoid fungal and bacterial disease problems. Putting a lawn in shady or boggy areas is asking for trouble.
Choose a grass type that is suited to your site and climate. Cool-season grasses are appropriate for most areas of Placer and Nevada counties. Tall fescue is a well-adapted variety that withstands our summer heat.
Test your soil and amend as necessary. Turf thrives with a pH of 6.5 to 7.0, a calcium to magnesium ratio of 10:1, and 5% to 8% organic material (OM). Adjusting the pH level will allow the lawn to properly uptake the nutrients it needs. Our foothill soils tend to be acidic and benefit from the addition of lime. Use calcitic lime to increase calcium levels and dolomitic lime to increase magnesium levels.
Once properly chosen and installed, regular maintenance can keep your lawn healthy. Top dressing with compost is an effective way to maintain organic matter levels. A commercial, bagged product will avoid introducing weed seeds common in homemade compost.
Lawns with high organic matter content need less fertilizer. Apply an organic fertilizer only if soil tests indicate it is necessary. Be aware that not all products labeled as “natural” or “organic” truly are. Look for OMRI certification.
Proper mowing is critical to lawn health. Mower blades should be kept sharp. A dull blade will tear the grass blade, leaving it more susceptible to disease. Grass should be kept to a height of 3 to 4 inches and you should never remove more than 1/3 of the blade length at a time. Longer grass blades allow for greater photosynthesis and shade out weed seeds, keeping them from germinating. Longer blade length also results in deeper roots, which in turn results in greater drought tolerance. Mulching mowers, which leave the cuttings on the lawn as they cut, return nitrogen to the soil and, contrary to popular belief, do not add to thatch build-up.