What’s the big deal about core aeration?

Core Aeration is Great for the Lawn

Every fall we see a flurry of activity at the rental stores, with folks loading up core aerators. We see signs all over the place, especially those placed illegally at intersections, promoting, “Core Aeration Special–$40!” And we see the professional LCO’s running their machines on our neighbor’s lawns. So, what’s it all about, Alfie?

The vast majority of soils in St. Louis are considered to be “clay loams”. West and southwest communities have rocky clay loams! These soils are productive, but they are very fine in their texture. Our subsoils are often pure clay. Fine textured soils are considered to be “tight” in the agronomic world—which means limited water penetration/percolation and oxygen exchange. A tight soil restricts root growth, limiting absorption of water and nutrients. Roots need oxygen to grow and thrive. The more large pores, the more oxygen. The more large pores, the better the water percolation. The more large pores, the better the nutrient penetration. The more large pores, the better the root growth. The better the root growth, the healthier the plant. Healthy turf tolerates stress better and has fewer disease issues.

In addition to our tight clay loam soils, our lawn mowers and even regular foot traffic increases compaction! Areas where the kids play, or the dogs run, become heavily compacted. This further exacerbates the situation. As tough as it is to grow plants in our “regular clay loam soils,” grass trying to grow in compacted areas lack vigor, thins out, or flat out dies.

The smart folks in the crowd are wondering when I’m going to talk about how core aeration helps to decrease thatch. Am I right? Pat yourself on the back if you’ve wandered there. Indeed, another huge benefit of core aeration is that the soil plugs deposited upon the soil surface contains millions upon millions of beneficial microbes. Maybe billions, I’m not sure. As that soil core breaks down the microbes help to break down the thatch layer. The issue of thatch management is something deserving its own newsletter. But know that fescue lawns DON’T develop thatch. Grasses that spread laterally do so with rhizomes (below ground shoots) and stolons (above ground shoots), which are more resistant to decomposition than leaf tissue. Zoysiagrass is notorious for developing thick thatch layers. Bluegrass will also develop thatch. Up to 3/8-inch thatch is usually OK! More than ½ inch of thatch is not good. Thatch actually gets to a point that it repels water. If you have more than ½ inch of thatch you should consider renting a “dethatcher”, properly called a vertical rake. Don’t rely on the core aerator for thick thatch situations. Dethatch cool season lawns in September to October. Dethatch zoysiagrass in June or early July.

Jeez, I’m really rambling. The best way to increase water, nutrient and oxygen exchange, reduce compaction, decrease thatch, and increase root growth of turf is to core aerate. Sidebar here, folks:  it’s pronounced “AIR-ate”. Not “AIR-e-ate” (definitely hoosier!) A core aerator removes plugs of soil out of the ground, 3/8th inch to ½ inch in diameter. For the millennials in the crowd, the ones that NEVER helped their parents do chores (except occasionally vacuuming the crumbs off the couch in the basement) the soil plugs look like dog poop. Thousands upon thousands of dog turds! Maybe hundreds of thousands. Not chihuahua-sized, not retriever-sized, but more like Pomeranian-sized. You want those holes to be 1.5 inch to 3 inches deep. The deeper the better, but the deeper the plugs are pulled, the greater the risk of puncturing irrigation lines, piercing electric dog lines and for sure, the damn cable company lines! Call 1-800-DIG-RITE and give them a minimum of 3 days’ notice, but know that they prefer 10 days’ notice. Dig-Rite won’t mark electric dog fences—so call your vendor for that. For the dullards in the crowd, you shouldn’t waste your money aerating bone dry soil! I’ve seen neighbors pay good money to pull ½ inch to ¾ inch cores—what a waste of money!

Cores.jpg

If you’ve conducted a soil test in the past few years, it’s likely the results indicated a need for lime (calcium, to raise pH), magnesium (Mg), phosphorous (P) and potassium (K). The only nutrient in the aforementioned list that will percolate (move deeper) is potassium. But it’s still a helluva lot less mobile than nitrogen (N), which literally moves with the water. Calcium, magnesium and phosphorous are IMMOBILE nutrients, meaning if you apply them on the soil surface, it’ll take a 2-3 years to move ¼ inch deep. We want these nutrients to be available to the roots for uptake. So, here’s the answer to the $64,000 question. Or is it the $69,000 question? Where’s Yogi when you need him?  Core aeration is an essential element for adjusting our soil pH, and to provide the turf with the amount of P and K that it needs for optimum growth!

Are you a “recreational limer?” That’s what the PROS call you goof balls that lime every year, without the benefit of a soil test. The optimum soil pH for turf is 6.2 to 6.8. That’s considered to be slightly acidic. Liming atop the soil surface is moronic.  And most of you don’t know that the FILLER in the 50 lb bag of fertilizer is coarsely ground limestone—big grits. A bag of 18-0-4 fertilizer has 18% nitrogen, 4% potassium and 78% large grit limestone. It’s literally a small rock. It’s essentially useless for adjusting soil pH. Re-read that last paragraph, if you’re confused.

Most lawns benefit from annual core aeration, best done in the fall. After you do this, you MUST water because you’ve opened up tremendous surface area for the roots, making it more susceptible to drought for the first 2 to 3 weeks. WATER! Those teaser adds for the $40 aeration are for single passes, usually with old machines. And the seed those guys use is pure crap—usually called “contractor mix” meaning a lot of annual ryegrass (crap) and weeds. New machines like that used by the Turf Guys at THE Turf Plan® have at least 35% more hollow core tines than the walk behind units. That equates to more plugs per pass. It’s best to at least do a “double pass” on your trouble spots. The more passes, the better in your thin or weak areas.

Any questions?

Now get to work! Get it done by mid-October, for the highest probability of success.

Trav

 

 

Beware the bad advice–there’s lots of it!

Idiots on the Airwaves

This past Saturday morning, while running errands for the family (not just my wife, but my daughter…WTF?), I had occasion to listen to a popular talk show host on the AM airwaves. I concede that this person has a few key strengths (indoor horticulture, annuals, perennials) in the broader field of horticulture, but his understanding of the SCIENCE of pesticides, especially herbicides, is woefully inadequate. Every summer, right on cue, this goofball says, “Summer weeds have hardened off so much, you really can’tkill them with herbicides!” What a load of crap! He proclaims this for both nutsedge and the entire collection of broadleaf herbicides. He’s dead wrong!

Before I skewer him on his abject stupidity in this specialty area, I’ll try to give him the benefit of the doubt. I’m a fair guy…even-tempered…open-minded—for an Irishman (50%). Maybe he’s thinking about those huge mats of crabgrass, two feet in diameter, or a hefty clump of goosegrass (aka “silver crabgrass”)(below left). Or maybe it’s an established area of deep-rooted black medic (below right). [By the way, the photo of black medic also has some white dutch clover in the photo–both are legumes–and both are tough weeds, but black medic is tougher!] These tough weeds become quite noticeable in late summer because they love the heat and they get very large. Herbicides have their limits–they kill small seedlings easy but an established monster weed won’t be controlled. There are no “selective” POST herbicides that will kill these tough weeds with only one application, this time of year. A “selective” herbicide means it will kill weeds but not grass (if used properly). But a non-selective herbicide, glyphosate (Roundup), CAN kill all these weeds, along with the turf!. STOP HERE! It’ll take at least two applications of glyphosate to kill established black medic. It will take at least 3 applications of common retail broadleaf weed killers to kill established black medic.

Herbicides used in turfgrass work by preventing weed seeds from developing (PREEMERGENCE or “PRE”) or killing established weeds after they are emerged (POSTEMERGENCE or “POST”). Every single herbicide used in turf can injure turf if over-applied, and most herbicides can even kill turf if horribly over-applied. There are “easy-to-control” weeds and there are “tough-to-control” weeds for every product used in your lawn and landscape. For example, dandelion is an “easy” weed for the multitude of broadleaf weed herbicides, while wild violet is a tough weed (3 applications required). Crabgrass is an easy weed for PREEN to prevent but nightshade is a tough weed for this product. PRE herbicides cannot control weeds beyond the seedling germination stage and POST herbicides work best on weeds less than 4 inches tall/wide. So our talk show host is only partially right about why herbicides might disappoint when applied in late summer. THE WEEDS ARE TOO FREAKIN’ BIG! They aren’t “tougher!”

Halosulfuron, the best herbicide on the face of the earth for control of nutsedge, is sold under “at least 3 different names, such as PROSEDGE, SEDGEHAMMER, and NUTBUSTER.  It still works GREAT right now! But the host of this show will tell you otherwise. [SIDEBAR: i did 75% of the development research for this herbicide while employed by Monsanto in the mid- to late-80’s, and it was introduced as MANAGE herbicide. I know WTF I’m talking about!] The broadleaf herbicides (no fewer than half a dozen) will still control weeds 4 inches tall if you apply them now, as long as it’s an easy-to-control weed.  

In summation: this guy doesn’t know crap about herbicides and weed control.

The Value of Compost

There are two ddifferent guys on two different stations that over-promote their proprietary compost blends. Not just for turf, but for ALL lawn and landscape woes. Compost is wonderful as a topdressing in turf, or when incorporated into the native soil when you’re establishing new beds. I don’t recommend it as a mulch because it becomes very powdery when it dries out. Heavy rains or heavy irrigation can wash compost downslope quite easily.

My beef with these two hosts is that they OVER PROMOTE the nutrient content of compost, and one says you don’t need to fertilize your lawn all season long! This is just pure crap.

The vast majority of our soils in St. Louis are typically adequate in phosphorous (P) and potassium (K) thus good turf management generally comes down to proper management of nitrogen (N). Fertilizer values for these there macronutrients are provided in the order of N-P-K. Compost typically 1-1-1. Furthermore, the nitrogen in the compost is very slowly released, in YEARS. Not days, not months, but YEARS. It may take 3 years for all the nitrogen in compost to be made available for use by plants. Compost usually has about 1% phosphorous, but it is essentially unavailable for several years. Finally, compost has about 1% potassium and it is readily available.

Let’s get back to the N, because good turf is all about the N! Healthy cool season turf in the transition zone needs between 2.5 and 4 lbs of N per season, per 1,000 sq ft. By simple math there is no way a single application of compost will provide you with a decent looking sward. We always want to limit our nitrogen to only 1 lb of actual N per 1,000 sq ft in a single application. With compost having only 1% nitrogen, that’s 100 lbs of compost per 1,000 sq ft. That’s certainly “doable” but a lot of work.

There’s nothing wrong with adding compost to the lawn, especially if it’s applied as a top-dressing after heavy aeration and seeding. There are billions upon billions of beneficial microbes in compost which serve to break down thatch, improve soil structure, combat pathogenic fungi, and improve aeration.

In summation: these guys should stop over-promoting compost as an adequate source of nitrogen.

Remember folks, the month of September makes or breaks the turf studs from the turf duds. If you aspire for a great lawn, work hard now through mid-October.

Stay cool!

Trav

 

 

 

NOW (SEPTEMBER) IS THE TIME FOR TURF REPAIR!

In the world of turf, September is for winners!

It’s really annoying how we’ve been trained by the big manufacturers and retailers that our first springtime application of crabgrass preemergent is STEP 1.

STEP 1 should be in sync with the growth cycle of our cool season turf, which would be our first fall application of nitrogen.

NOW is the time to prepare for turfgrass renovation. Print this document off. Read it twice.

If you’re going to RENOVATE, which is starting from scratch, late August and September is the time to do it, because you need to kill off your existing lawn and weeds with Roundup®.  It’s best if you start early enough to make two applications of Roundup, 3 to 4 weeks apart. If you’re going to OVERSEED, you want to be done by mid-October.  Basically, you overseed decent turf, and you renovate crappy turf.

Typically, we start re-seeding in early to mid-September, because grass seed will germinate rapidly with warm soils. Cool nights help keep the soil uniformly moist. The fall weather will have a profound influence on success. You want to take advantage cool weather (85F day / <60F night) and moisture. But if it gets hot and humid after the turf germinates, apply propiconazole fungicide to protect those tender seedlings. You will need to irrigate lightly and often for the first 3 weeks, so don’t plan a vacation after you do this.

Why RENOVATE?  If your lawn “sucks”, then it’s better to kill it off and start over. If you can see the soil on over 40% of the surface, your lawn sucks. Time to do something drastic. If your yard is mostly weeds…your lawn sucks. Kill it and start over. Or, at least spray Roundup on the weedy patches. Solid patches of turf that have survived need not be destroyed! That’s tough turf!

Why OVERSEED?  Adding new and improved varieties into an existing turf sward will allow you to improve your turf, more slowly than renovation, but it’s less destructive. Coupled with core aeration, renovation can enhance quality tremendously. Core aeration literally pokes hundreds of thousands of holes in your soil. Those holes increase the oxygen supply to the roots, which is critical because of our heavy clay soils. In addition, the cores that are left on the soil surface actually dissolve down on top of “thatch.” That soil is loaded with a microbial population that is hungry for thatch. AND, the soil cores will actually crumble/smash down atop the seed that you’re spreading, helping that seed emerge faster. Covered seed comes up much faster than exposed seed.

Can you use a “dethatching machine”?  You can use a “dethatcher” to work your lawn over. This is an old-fashioned machine that basically just beats the hell out of the turf. You need to set the spinning metal tines so that the only cut 1/8” deep groves in the soil. It works best if you scalp the grass first. CAUTION! Don’t scalp your turf in one pass—mow it successively shorter 2 to 3 days in a row. If you can set your mower at 1.5 inches, that’s scalping!  Especially if you’ve been cutting at 3.0 to 3.5 inches all summer. Clean up the mess before you spread grass seed. Rake it and get rid of all that organic trash.

WARNING:  this method is labor intensive (but usually worth it). Zoysiagrass swards benefit from this every 3 to 4 years or so but DO NOT AERATE OR DETHATCH ZOYSIA AFTER AUGUST! That’s best done in June or July. I recommend that you core aerate, versus using the dethatcher.  Read on.

 

COMPLETE RENOVATION TIPS (For crappy lawns!):

1)Kill the lawn section with Roundup ASAP. Don’t mow before spraying! Roundup will work better with all the fresh, succulent tissues to absorb and translocate more herbicide to the roots. Don’t be a tight wad with the Roundup. Buy the concentrate and use 5 oz/gallon. Be sure you buy “plain” Roundup.  Don’t use the “extended” control, “fast-acting” or poison ivy variants! Use a hose-end sprayer and be careful that you don’t create a lot of mist, which will float to your favorite ornamentals. Or your neighbor’s lawn—they’ll be pissed.

2)After four to seven days scalp the lawn with a mower. Call 811. It’s free and they want 3 days advance notice. You really want to cut the cable lines, especially your neighbors’ cable. Mark your own hazards, too, like irrigation heads and underground doggie-shock lines. Dog lines are usually deep enough to avoid damage, but that damn cable company usually only buries their cable one inch deep. If by chance your machinery cuts a cable line, don’t let them bully you into paying for repairs. They are supposed to put their cables ~6 inches deep…RIGHT!

3)     WHAT TYPE OF GRASS SHOULD YOU USE?  For non-irrigated, sunny swards, turf-type fescue is the best type of seed to use.  About 35% of the swards in the transition zone will do best with this type of seed, especially for new subdivisions, lacking large shade trees. It is by far the best of the cool season species for full sun without irrigation. But, the best turf for deep shade is a blend of three very shade tolerant, fine-bladed fescues:  meadow fescue, sheep’s fescue and creeping red fescue. If you haven’t had much luck growing turf-type fescue in non-irrigated shade, try a 3-way fine fescue mix. Another great blend of seed is a blend of turf-type fescue and a medium-green colored bluegrass. Bluegrass spreads laterally by rhizomes, thus it will help fill in the divots and holes caused by disease and moles. A pure bluegrass sward is a thing of beauty…but bluegrass is pretty tough to grow for most folks. If you don’t have an irrigation system, don’t even try it. Bluegrass doesn’t like FULL sun, and it doesn’t like deep shade, either. If you’ve got a yard that has 20 to 40 year old shade trees that provide up to 6 hours of shade in each “ecosystem,” you can probably grow bluegrass. The newer varieties are a hellofa lot tougher than they were just 15 years ago. If you’re not sure, go with Winning Colors Plus blend…turf-type PLUS bluegrass. The bluegrass will grow where it’s happy, and the turf-type fescue varieties will grow where they’re happiest.  Talk about a win-win!

5) Get a soil test if you’re having problems growing grass in the shade! The proper pH (soil acidity), phosphorous and potassium levels may help you out…and most shady soils have acidic soil and low fertility. Those tree roots are competing for more than sun and water. Tree roots will scavenge all the P and K in the topsoil, causing low fertility.

6) After you scalp the lawn look and see how many new weeds have emerged within a week. More than likely you’re going to see how inept you were on your first pass at nuking the lawn – retreat with Roundup. If you see tiny weeds sprouting and green tissue all around, retreat the entire area. Trust me, it’s worth the extra time, energy and money spent to start with a weed free area.

7)Five days after the second application of Roundup, rent a “verti-slicer” or “slicer-seeder”. This machine cuts a grove into the soil, and then drops seed into the grove. Having good seed-to-soil contact will dramatically enhance germination and establishment. There is no need to set the blades any deeper than 1/8th inch deep!

8)If you can tend to all these tasks, and have the seed in the ground by mid-September, you will be rewarded with a fabulous lawn. It will be green and thin this fall, but lush and full by next May –- a real “award winning” situation. Try to be DONE by October 1st. You’ve get a 95% chance of success if you’re complete by this date.  After October 15ththe odds of success diminish, depending upon the growing conditions in November. If turf can get established to the point that you have to mow weekly in November, you’re in great shape.

9) For OVERSEEDING use 4-5 lbs of turf-type fescue per 1,000 sq ft, 5 lbs of shade fescue blend, and 1.0 to 1.5 lbs/M of bluegrass.

 

OVERSEEDING TIPS (WHAT MOST OF YOU NEED TO DO):

1)New turf varieties are more disease and heat tolerant than older varieties. That’s why you should overseed every couple of years.

2)Cut your lawn successively lower from 3.5 inches down to 2 inches. Don’t do it all it once folks, because the resultant hay will interfere with your seeding.  If you can bag, we recommend that you cut it every day, lowering the deck on the mower over 2 to 3 cuttings.

3)Rent a core aerator, which pulls a plug of soil, approximately ½” wide by 2 to 3” deep.

4)Get your BROADCAST SPREADER out of the garage (if you’re still using that rusted-out, nasty-ass old drop spreader, get rid of it), set the opening around ½ to 5/8th inches for turf type fescue, ¼ inch for bluegrass. Spread 25% of your total seed on the turf BEFORE you make your first pass with the aerator. You read that right—BEFORE your first pass. You want the cores to cover the seed more than you want the seed to drop into the holes. Concentrate on the really barren areas with the first pass of seed.

5)Make 1-2 passes with the aerator.

6)Spread another 25% of your seed.

7)Make another two passes with the aerator, perpendicular or diagonally to the first pass. All the plugs that you pull out of the ground are valuable!  They’re covering up seed, in addition to providing more air to the grass roots.

8)Spread the last 50% of your seed.  If you followed directions, you made at least two passes in good turf, and as many as 4 to 5 passes in your problem areas.  All the seed that falls into the bored holes, and all the seed that ends up under a “melted” core, will germinate rapidly.

10)Leave the soil cores where they are – the microbes in the soil help break down the thatch. The bored holes enhance water penetration into your soil.

11) This method is the BEST, but if you’re short on time and labor, just aerate the crap out of the yard (as many times as you can), and follow it up with no less than 4 lbs/M of turf-type fescue seed.  This method is perfectly suitable, and will save you a lot of time.

12) Crucial to your success is seeding at the right rate. For NEW SEEDING or RENOVATION with turf-type fescue and shade fescue use 10 lbs of seed per 1,000 sq ft, and 3 lbs bluegrass.

 

FERTILIZATION:  If you know your ACTUAL SWARD SIZE, and you have a decent spreader, you can safely apply “regular” fertilizer, at a maximum of 1.0 lb of actual nitrogen per 1,000 sq ft. It need NOT be “starter fertilizer.” Starter formulations have lower nitrogen and higher phosphorous. Most of us have HIGH soil phosphorous anyway, thus any nitrogen is OK. If you can’t start till late September I recommend you still apply nitrogen to the lawn in late August to early September.

BAD SPOTS ALONG PAVED SURFACES:  Seed won’t grow well if it’s just scattered atop the soil.  For the really bad spots, we suggest you cover the seed with either PennMulch® or bagged topsoil. Avoid straw except for very large areas. Straw introduces a lot of weeds.

WATERING TIPS:  Use frequent irrigation to get the seed up. The first couple of days after seeding you can water with your normal irrigation cycles. As soon as the seed comes up, though, you’ve got to sprinkle the turf babies with frequent, shallow irrigation. It’s critical that the top ½ inch of soil NOT dry out extensively. If you own an irrigation system, just run it 3X day with about 2 to 3 minutes per station. I can’t tell you exactly what to do for your own yard! You need to be observant. Don’t water so much that you turn the yard into a swamp, either. As the new grass gets taller, you go back to watering more deeply and less frequently. Within 3 weeks after the turf is up, you should be able to water every other day.

MOWING:  Stay off the new grass while it is short and fuzzy. But when it gets to be about 2.5 inches tall, run the mower over it, cutting it around 2.0 to 2.5 inches. The turf can handle the foot traffic, but don’t rip it out of the soil with your mower tires. Slow and steady!

DON’T LET LEAVES PILE UP:  Don’t let falling leaves cover up your newly seeded areas. While established turf can handle a once-per-week mowing, new turf should be leaf free most of the time. This is where a blower works wonders.

FUNGICIDE:  When the new seedlings are one inch tall, apply propiconazole fungicide to provide a “health boost”. It will protect the seedlings from the key diseases that harm turf, especially if it’s hot and humid.