| Be Smart! Be Thrifty! Be Really Cool! Get Your Soil Tested!
By Mike "low pH; high phosphorus" McGrath
Did you know that homeowners use an average of four times more agricultural chemicals per square foot than farmers? Some big-city water quality specialists tell me that runoff from those people's lawns and gardens is now a bigger water pollution problem for them than farms and industry combined!
Well, one way we all can help keep our drinking water and streams clean and unpolluted (and our garden plants happier and healthier!) is to make sure we don't over-feed our gardens or add lime to lawns that don't need it. But, of course, some times a little fertilizer IS necessary. So how do you know whether or not your lawn or garden DOES need something added?
It's actually very easy and inexpensive to find out, thanks to an amazing service available to every one of us gardeners here in the mid-Atlantic region. It tells you lots of wonderful things you didn't know about your soil, helps you improve your plants chances of doing better, AND prevents you from adding things that your landscape doesn't need. It's a soil test--and you have access to one at a very low cost through (take a deep breath now) your County Cooperative Agricultural Extension Service. Whew--that's a mouthful--eh?
Seriously, soil tests are one of the great bargains of gardening. In fact, they're (get ready now) "DIRT CHEAP!" (Get it? 'Dirt cheap'? Boy--you people are tough...) And they're lots of fun--these horoscopes of horticulture reveal the secrets of your soil by doing a divining of your dirt!
All the instructions on taking a proper sample will come with your test kit. But basically, you'll use a stainless steel or plastic trowel (or other non-reactive-metal scoopy thing) to dig samples of soil from several places in your garden, mix those samples together well in a CLEAN (non-galvanized) bucket or large glass jar, then fill up your soil test collection bag or box with some of that mix and mail it in.
Every state's services and prices are a little different (details below). But no matter where you live, you start the dirt rolling by getting in touch with your local Extension office. One of the easiest ways to do this is on the web. We've listed a few sample web address for you, but you can also just type "Cooperative Extension" + Alabama (or the name of your state) into a search engine. That state web site will list all the local offices by county. Pick yours, then give them a call and ask how they supply their test kits.
Almost all offices will mail a kit directly to you. Many others will also provide a list of nearby nurseries and other businesses where you can pick up a kit. Some others have very innovative programs for distributing the kits. In Virginia's Fairfax County, for instance, you can pick up a soil test kit at any public library! Or ask when would be a good time to actually come by and visit your local office to pick up your kit--your local extension office offers lots of free publications and services for gardeners, and many have special children's programs and events you might like to learn about. Some have plants, animals or displays there, and some have full gardens outside! And it's always a great idea to get to know your local extension agent personally--they can be a great resource for gardeners.
Anyway, you'll fill the little bag or box that comes with the kit with your soil sample, answer some question on a form, mail it all in with a check, and you'll soon get back a psychic reading of your soil!
It's always a lot of fun to see the results. The forms are like one of those "your fortune" cards from a machine that tells you your weight--except this 'card' tells you the future of your garden plants! The results will also come with recommendations about how to make any changes the test results suggest are necessary. The local extension office that supplied your kit will also get a copy of everything--so you can call them up and ask specific questions about the results and recommendations.
IMPORTANT NOTE ABOUT THOSE RECOMMENDATIONS: Your test results will probably recommend chemical fertilizers to correct any deficiencies, but if you insist, your local agent should be able to suggest organic alternatives. (If they refuse, please let us know.) Be sure and mention if you have access to ashes from a wood stove or fireplace--they can be used instead of lime to raise your soil's pH, and they'll add the essential nutrients phosphorus and potassium at the same time. And be doubly sure to tell them if you have access to compost--that rich black super-soil will improve your soil's percentage of organic matter and cure virtually any nutrient deficiency!
OK? Good! Now, here's what some different states test for and charge.
Delaware: The Small Wonder has a GREAT basic test; for $7.50 you'll learn your soil's pH, its levels of Phosphorus, Potassium, Calcium, Magnesium, Manganese, Copper, Zinc, and Iron AND the percentage of organic matter (perhaps the ultimate indicator of soil health!). They'll also test your soil for lead contamination for $10. The soil test lab is at the University of Delaware; if you have any questions your local agent can't answer, call them at 302-831-1392. Web site: [ http://ag.udel.edu/extension/ ]http://ag.udel.edu/extension/ (You can find your local office there, but no real soil test info; it just tells you to call the phone number.)
Maryland: For a mere eight dollars, you'll learn your soil's pH; phosphorus, potassium, calcium and magnesium levels; percent of organic matter, AND get an analysis of your soil's texture, revealing the percentages of things like sand and clay that make up YOUR dirt. Nine optional tests are also available at extra cost, but sadly, a screening for lead is not one of them. (They'll refer you to a private lab or suggest you send it to one of the states that DOES test for lead.) The tests are performed at the University of Maryland; you can call the lab toll-free (in Maryland only!) at 1-800-342-2507 or visit their web site at http://www.agnr.umd.edu.
New Jersey: The Garden State's 'standard fertility test' costs $10, and reveals your levels of Phosphorus, Potassium, Calcium and Magnesium, soil pH and levels of five micronutrients. A lead test costs ten bucks. Their lab is at Rutgers: 732-932-9295. Web site: http://www.rce.rutgers.edu click on "Lawn and Garden", then the soil test link.
Pennsylvania: It only costs six bucks to learn your dirt's levels of Phosphorus, Potassium, Calcium and Magnesium and it's pH. The "Sorbed Metals Test" costs $55, and reveals how much (if any) chromium, copper, zinc, lead, nickel, and cadmium is lurking in your land. A lead test alone is $20. Lots of other tests available; check their website http://www.aasl.psu.edu for details. The main testing lab at Penn State (814-863-0841) will answer any questions.
Virginia: For a mere seven dollars, they'll reveal your soil's pH, phosphorus, potassium and calcium levels AND the amount of boron and four other important micro-nutrients. For an extra $3, you can also have your sample tested for the amount of organic matter present. Unfortunately, Virginia doesn't test for lead--they'll refer you to a private lab for that. The soil tests are run at Virginia Tech; 540-231-6893; on the web at http://www.ext.vt.edu
Washington, DC: Did you know that, even though you're not a state, you still have your very own extension office? Well, you do, and for nine dollars, their basic test reveals your soil's pH, levels of potassium, phosphorus, calcium and magnesium, the percentage of organic matter, 'lime levels' (just like it says--the amount of lime, an amendment often added to lawns, that's in your soil), and "cation exchange capacity" (simply put, this is the ability of your soil to hold nutrients based on its texture; for instance, if your soil is really sandy, nutrients will wash away quickly). Urban gardeners may want to also get a heavy metal test. No, this doesn't measure how much you like really loud music! For $37.50, it tells you how much copper, zinc, cadmium and lead is in your soil. They'll be happy to mail you a test kit; just give the office a call at 202-274-7115 (or call the extension agent directly at 202-274-7166). Or pick one up in person during business hours--the office is at 4340 Connecticut Avenue on the UDC main campus.
Some important terms to know
pH: Whether your soil is acidic or alkaline and by how much. Many soils in our region tend to be acidic, and if your test results show a low pH, they may suggest adding lime to bring the numbers up. Low numbers, like 5 and 6, are acidic; 7 is neutral; higher numbers are alkaline. Most garden plants like a slightly acidic soil, around 6.5; azaleas and other acid-lovers like it lower.
Phosphorus and Potassium: Two of the most important nutrients we add to our gardens--they're essential for good root growth and getting lots of fruits and flowers. (They're the "P" and the "K" on fertilizer labels with the three "NPK" numbers.)
Nitrogen: The "N" in NPK; the food that makes plants grow big. Labs don't test for nitrogen directly, but "percentage of organic matter" is a good indicator of how much you have.
Calcium: An important plant nutrient often deficient in our soils (not mine--I put lots of eggshells in my compost and planting holes!)
Percentage of Organic Matter: A measure of the richness of your soil; high levels mean happy plants and lots of beneficial life in your dirt. Gardens that have had a lot of compost mixed in over the years have high levels, while sandy and clay soils that have been fed with chemicals tend to be low.
Micronutrients: Teeny tiny little plant foods. Sorry. These elements, like boron, are essential in low amounts, but can be toxic in high ones. Most home gardeners don't need to worry about them, but it's nice to know if it's included in your state's basic test. (Varies greatly from state to state.)
Lead and other heavy metals: Unfortunately, the soil in some gardens is contaminated. One of the biggest concerns is lead, which can 'flake' into garden soils when old lead paint peels off a house. Urban gardeners or folks with garden areas close to an old home may want to spend the extra for a lead screening. And if you fear your garden may have once been a dump, service station or other contaminated site, you'll want a full heavy metal screening.