1. soil pH

2. phosphorous levels (“P”)

3. potassium levels (“K”)

If you follow our “horticulturally-sound” advice, you’ll soon be the “big kahuna of turf”, at least in your cul-de-sac or neighborhood. We know how quickly your sward responds to proper management, especially in the fall. THE Turf Plan^SM is predicated upon accurate application of fertilizer and/or pesticides. Once you’re sure how much actual turf you have (your “sward” size) your next step is to get a soil test. Read on.

A pH Short Course: The pH scale ranges from 0 to 14, with 7 being “neutral.” The pH level (a scale ranging from acidic to basic) has a profound effect upon the chemical reactions that occur in the root zone. If your soil is too acidic (“sour”), or extremely basic (“sweet”), your attempts to manage your turf will not yield the desired results. You don’t want a pH value of 7! Plants have a preferred range at which they grow, but the stuff we’re talking about here, turf, prefers a pH of 6.2 to 6.8. This is slightly acidic, but that’s OK. Maximum nutrient availability, at least those required for turf, occurs in this range.

You should test your soil every 3 to 5 years, especially if your sward is not up to standard.  Additionally, if you have ”problem area” it’s a good idea to run a separate soil test for that general are.  If you aspire to be the neighborhood lawn stud, soil testing will only get you there faster.

How to Take the Soil Sample

1. Decide if you need one general sample, or whether or not you’ve got some serious problem areas that you’d like to do some “detecting” work. If so, segregate your problems areas

2. Get a garden trowel or digging tool and a grocery bag

3. Before digging clear away the grass and organic debris (”duff”) in a 3” wide area. Watch out for dog poop.

4. Take a 3” x 3” x 3” cube of soil from 4 to 6 different spots in your yard, placing them into the grocery sack as you collect them. Our interest lies in the actual rooting zone for turf.  Backfill the divot with a nice topsoil.

5. If you have problem areas, repeat the process for the bad spots, but keep that sample separate!

6. Take the bag into the garage or covered area.  Leave it open to allow the soil to dry, until it’s very easy to crumble into small clods and homogenize (mix).  When the soil is in a crumbly state, carefully mash it all up with either a baseball bat or a piece of wood. Mix the sample evenly. This is important.

7. The soil lab only requires two cups of nicely granulated soil.  Use the remainder to fill the divots you took originally.  

8. Drop off your soil sample, being sure to write your name and phone number on the bag.  Go to the GARDEN PRODUCTS tab and purchase a soil test.  Once that’s complete, we’ll send your sample to the lab.

9. Results should be available within 10 to 14 days.  We’ll contact you with the results, and help you understand those results.

10. We recommend that you take your soil test between the months of March and June. That way, you’ll be sure to have your results in hand before September, the critical month for turf seeding and renovation.  One of the best ways to ammend the soil pH is to use a core aerator prior to fall overseeding.  But, we’ll warn you, you need to make at least 4 passes with the core aerator, to really poke your sward full of holes.

How to Adjust your soil pH Level: If your soil is acidic, adding lime will slowly bring the value into the optimum range. Most St. Louis soils are acidic, as you’ve already heard, hundreds of times. A soil test value will take into account the pH and it will provide an amount of calcium required to bring the soil pH into the optimum range. It might state: apply 150 lbs of lime per thousand square feet. No kidding, that’s three full 50 lb bags, over a 20’ x 50’ patch of grass! If your soil test calls for this, our recommendation is to apply a bag before May, then again in September and again in December. We don’t recommend applying it all at once! Applying lime after core aeration is even better, because calcium, the neutralizing element in lime, is not very mobile in the soil. The coring helps move nutrients deeper into the rooting profile, faster. The best time to use the core aerator is in September. This is “prime time” for repairing soil.

If your soil is basic, the soil test will tell you how many pounds of elemental sulfur needs to be applied. Don’t waste your time or money applying “aluminum hydroxide” to lower the soil pH. Sulfur is better, and less expensive. Plus, too much aluminum is toxic to plants! As with the liming recommendation, application of ground sulfur over two to three applications is more reasonable. And of course, it’s best to core aerate in advance of the application.

Think of soil pH this way. When it’s optimum, between 6.2 and 6.8, turf has an easier time obtaining all those micronutrients. Everything is in balance. It’s a “holistic” approach to tending turf. When too low or too high, the micronutrients are the first elements to give the turf problems.

P=Phosphorous: Most folks, especially those that have fertilized regularly, will get a soil test in which the result is “high” or “very high” P levels. That’s good from the standpoint that P isn’t limited. It can be bad, though! Too much P can form complexes with calcium, manganese, iron and molybdenum, rending them unavailable. Phosphorous is a very immobile element. That is, it stays put in the soil. Excessively high P can actually make nitrogen less efficient, too. That’s a problem. Applied onto the soil surface, it’ll take years to move into the top 2 to 3 inches of soil. Again, we recommend that you apply phosphorous fertilizer after a double pass with a core aerator, to help get the element into the entire root zone of turf. If your soil tests at high or very high in phosphorous, you should try to avoid applying fertilizers with this element. We try to provide products with little, to no P.

K=Potassium: Potassium, also called potash, is the element associated with “winterizer” fertilizers, or “stress conditioners”. It generally tests out in the high category here in St. Lou. Some U.S. soils are K deficient, but St. Louis clays have a lot of it. K is more mobile than P, but not nearly as mobile as nitrogen. Potassium is the number one positively charged element (cation) inside the plant. It’s involved in a lot of enzymatic activities and helps maintain the charge balance of a plant. Again, if your soil test results indicate a need for more K, it’s best to apply it right behind 2 to 3 passes of a core aerator. Incidentally, fireplace ashes are mostly potassium. Spread it thinly all over your lawn in the cool months of fall and winter, but be warned, the family mutt might track it into your house, onto your nice, new carpet. If this happens, you’ll be sleeping beside the dog, dirty feet and all…