LAKE FRIENDLY LAWN CARE

By Alexandra Andrews  

Reprinted from the Lake Boon Gazette Vol. 42 - August 2000

Concerned about our lake’s nutrient loading problem? Want a nice lawn?  Armed with some basic knowledge about soil, fertilizer, and turfgrass, you can have a green yard without adding to the lake’s growing weed problems.  And even better, you will probably end up spending less time and money maintaining it.  

Healthy, Living Soil: The Foundation

A healthy lawn is really a living system composed of the soil and plants, and the nutrients you add (compost, fertilizer, grass cuttings, air, light, water).  Healthy soil contains sufficient amounts of many “ingredients”: organic matter, clay, sand, silt, air, water, etc., as well as millions of microorganisms, earthworms and insects (including the eggs for predatory wasps which eat grubs!).  A healthy living soil supports a HUGE diversity of life, plant, animal and microscopic.

When you “feed” your lawn one of the available “4-step lawn care programs”, you replace nature’s checks and balances with an unnatural, self-perpetuating lawn chemical habit.  These programs often contain excess nutrients, herbicides and pesticides because they must work in most soils and climates in order to be a good profit-maker for the manufacturer.  They are not specifically designed for our site and soil conditions on Lake Boon .  Commercial fertilizers can overfeed your lawn, which means you have to water and mow more often. Over time, these mixes kill the naturally occurring predators of pests like “grubs”, and the microorganisms which decompose thatch, creating more work and expense for you: you need to apply more pesticides and you have to de-thatch, re-seed, and re-fertilize.  Plus, any unused fertilizer, herbicides and pesticides end up in our lake and drinking water.  

Soil Test

The first step in switching over to more ‘lake friendly’ lawn care is finding out what nutrients your lawn needs by getting a soil test.  The Extension Service at UMass/Amherst will analyze your soil samples for $12.  The complete analysis will tell you your soil’s organic matter content, pH, and nutrient levels, and will make recommendations for improving your soil for turfgrass planting. UMass will also test for lead or other heavy metals levels (good information for families with young children and older homes, where peeling lead paint may contaminate soil).

The ideal soil pH for growing turf is 6.3 to 6.8.  At this level, grasses take up nutrients most effectively and there is the highest level of microbial activity beneficial to them. New England soil tends to be acidic, and is usually “sweetened” with an application of lime. But be aware that what you water with will affect soil pH as well: if you water with town water or have a water treatment system, which raises pH, you may be making your soil too sweet.

Feeding the Soil—Compost and Fertilizer

If your soil has adequate mineral nutrient levels, and your soil pH is right, many lawns will need nothing more than an annual top-dressing of compost.  This means raking in ¼” or so of top-quality, finished compost at the end of the season.  Late summer and early autumn are good times to do this, because you may have some spots to re-seed and the compost will help germination. Commercial bagged compost is often fine enough to be put on the lawn with a spreader. Homemade compost usually has to be raked out. In between compost applications, leave the grass clippings on your lawn so you are returning some organic matter back to the soil. You can also chew up some autumn leaves with your lawn mower and leave them on the grass to decompose over the winter. Just a sprinkling, though!

If you use a commercial fertilizer, know what you are putting on your lawn and don’t put on too much. Commercial fertilizers are sold with a numeric rating describing the ratio of their three essential nutrients: nitrogen (N), potassium (K), and phosphorus (P). Nitrogen produces chlorophyll, that is, leaf growth and green color.  Potassium helps with stem growth and flower or fruit set.  And phosphorus is responsible for root growth and strong cell walls.

Most commercial lawn fertilizers are rated something like 29-4-4 , which means LOTS of nitrogen (29 lbs. per 100 lbs. fertilizer) and a little potassium and phosphorus.   Your lawn probably doesn’t need that much nitrogen. In fact, leaving the clippings on the ground to decompose can provide as much as 1/3 of your lawn’s nitrogen requirements!   Another advantage to maintaining a living soil: Soil microbes will “fix” nitrogen, that is make the nitrogen in the air available to the roots of your lawn grasses, further reducing the amount of nitrogen you need to apply as fertilizer. Pay attention to the form of nitrogen in your fertilizer: NO3 is the form you want, because in the form ammonium nitrate (NH4), the nitrogen is extremely volatile--it will “gas off” before your lawn’s roots have a chance to take it up. 

 In the right soil, beautiful grass can grow just fine without additional fertilizer!  However, if you are going to fertilize your lawn, calculate how much you will actually need before you just lay it down according to the package directions.  Any fertilizer (as well as the herbicides and pesticides in the mix) not used by your lawn will end up in the air and the lake, feeding weeds and wasting your time and money. Figure out how many square feet of lawn you have (give or take 100 feet or so) and figure out actually how much nitrogen your lawn needs: Bluegrass requires about 5 lbs. of nitrogen per 1000 square feet of lawn per season.  Ryes and fescues require 3 lbs. per 1000 square feet.  Don’t forget to allow for nitrogen returned back to the soil when leaving the clippings in place, as well as any provided in the water you use!

            For example: Let’s assume your lawn is 1000 square feet, and about 1/3 bluegrass, 1/3 fescues, 1/3 ryes.  (Identifying grass species is a whole lot easier said than done; it’s probably okay to assume that it is a mix like this example.)  That means the nitrogen requirements for an astonishingly green lawn would be somewhere about 4 lbs. per season, applied in 4 parts: May, June, July and August.  Take the 5-3-4 fertilizer (the 5 means 5 lbs. nitrogen for every 100 lbs. of fertilizer), and apply about 20 lbs. of fertilizer for each of those 4 feedings.  Soil temperature must be around 45-50 degrees in order for the right microbial activity to be present to allow the nutrients to release, so you don’t want to make your first application too early. 

Non-toxic Treatments for Pests and Weeds

Some plants, such as Queen Anne’s Lace, milkweed, black-eyed suasions and daisies, attract beneficial insects, such as grub-eating wasps. (Some types of ants eat grubs as well.)  “Milky Spore Disease” powder is also effective in controlling grubs when used several times a season, and may be applied anytime when the soil is moist.  Adding beneficial soil nematodes is another form of grub control.

                Corn gluten (available in several brands) is a non-toxic form of weed control.  For best crabgrass control it must be applied before the weed seeds germinate; around here, that’s when the forsythia bloom in the spring.  Some organic fertilizers are available with the corn gluten and milky spore included.  Please remember that a healthy, living soil will contain a variety of organisms (including grubs and their predatory diseases, insects, etc.), and if your soil is healthy, your lawn will survive and revive if the pests and weeds flare up periodically.  Most turfgrasses are aggressive enough to crowd out weeds once you let them get the upper hand and give them the conditions they like. 

 It Doesn’t Happen Overnight

Weaning your lawn from heavy fertilizer, herbicide and pesticide use will be more successful if you take one or two seasons to do it.  You will find that overall, an organic (or nearly-organic) lawn is just as green as the chemically dependent, over-fed lawn, and you won’t have to “stay off the grass” for a few days after the application of pesticides and herbicides that may not be necessary.  The lake and our drinking water will be the better for it, and you will save time and money. 

 Sources:

The information contained in this article comes from a number of sources, particularly New England Wildflower Society’s course in Organic Lawn Care. 

·         See articles on lawn care at Connecticut College’s web site: http://www.canr.uconn.edu/ces/garden/index.html

·         For other native groundcover and wetland buffer zone plants, visit Garden in the Woods/New England Wildflower Society, 180 Hemenway Road, Framingham, MA (508) 877-7630. http://www.newfs.org/garden.htm

·         Soil and Plant Tissue Testing Lab, West Experiment Station, University of Massachusetts, Amherst, MA 01003, (413) 545-2311, or www.umass.edu/plsoils/soiltest/. This web page also features a link to the UMass Extension Service.

·         Massachusetts Horticultural Society Help Line, (781) 235-2116. Answering questions Monday, Wednesday and Thursday from 10 a.m. to 2 p.m.

·         Tower Hill Botanic Garden/Worcester County Horticultural Society, Boylston, MA, (508) 869-6111 (they have a help line as well—from 2 to 4 p.m. on Wednesday) http://www.towerhillbg.org/

Sources of fertilizers, corn gluten, grub control, etc.

·         North Country Organics, PO Box 372, Bradford, VT 05033 (802) 222-9661 http://www.norganics.com/index.html - Natural No-Phos (6-0-6) especially formulated for areas near streams or lakes…Their phone number is 802-222-4277 Paul Sachs is the owner; can ship to homeowners or to your local nursery. 

·         Gardener’s Supply Co., 128 Intervale Road, Burlington, VT 05401 (800) 863-1700 (www.gardeners.com)

·         The Green Spot Ltd., 93 Priest Road, Nottingham, NH 03290-6204 (603) 942-8925 http://www.agrobiologicals.com/company/C1271.htm

·         Peaceful Valley Farm Supply, PO Box 2209, Grass Valley, CA 95945 (530) 272-4769; http://www.groworganic.com/

·         Gardens Alive, 5100 Schenley Place, Lawrenceburg, IN 47025  (812) 537-8651       http://www.gardensalive.com/index.asp