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Prevent Poa Annua (Annual Bluegrass) Now

This is a reminder for all of you who have asked me about killing Poa Annua (see photo) back in spring. Now is the time to put down a preventer before it has a chance to germinate.

This is an early spring picture of Poa Annua in a Bermudagrass lawn.  Notice the light colored seeds.

This is an early spring picture of Poa Annua in a Bermudagrass lawn. Notice the light colored seeds.

Lawn weeds like Poa Annua (Annual Bluegrass), Common Chickweed, and Henbit are “Winter Annuals”.   This means they germinate in fall, thrive in spring and then die during summer, but not before scattering seed so the cycle can start all over again in fall. (“Summer Annuals”, like Crabgrass, Foxtail and Barnyardgrass, have the opposite cycle of germinating in spring, thriving in summer and dying just prior to winter, but not before scattering seed so the cycle can start all over again in spring.)

If you vowed last spring that you wanted to stop these winter annual weeds from invading your lawn, you need to pick up a bag Scotts Halts or Scotts Turf Builder with Halts so you can treat your lawn now. (One of these Halts products is the correct product to use even though it says to apply in spring to prevent crabgrass.  Read further in the directions and you will see info about applying this time of year to prevent Poa Annua and other winter weeds) Be sure to water after application.

Caution: If you are planning to plant grass seed this fall, you should not spread weed prevention in those areas as it will keep your good grass seed from germinating.

Should You Kill Crabgrass Now?

What to do with Crabgrass in your lawn in late August: Kill it or do nothing since the frost will kill it in a month or two?

Crabgrass germinated in this area where the grass was thinned from a lawn fungus problem. It is easier to kill before it gets big.

Crabgrass germinated in this area where the grass was thinned from a lawn fungus problem. It is easier to kill before it gets big. (click photo to enlarge)

First a little bit of background. Crabgrass is an “annual” weed, which means it germinates in spring, then in summer the plants produce seed and then it dies in fall with the first frost. Spring applied crabgrass preventers will stop most of the seeds from growing, however generally not all of them. Just when your lawn is thinned from fungus disease or insects, a stray crabgrass seed germinates in the weakened areas. The crabgrass then hunkers down flat where your lawnmower can’t reach and spreads to choke out your remaining good grass. Each plant produces seeds… lots of seeds! These seeds then germinate next spring so even more crabgrass plants can threaten to win the battle for your lawn.

If you decide to wait till fall to let the frost kill your crabgrass, you will miss the chance to kill it before it produces more seeds before it is killed by frost. So I would suggest killing it now before you get more crabgrass seeds for next year.

If you want to kill crabgrass without killing your good grass, spray it now with Ortho Weed B Gon MAX plus Crabgrass Control. You can use this spray on any lawn type except St. Augustine, Centipede and Bahia. This spray works best when you go after younger crabgrass plants. For larger crabgrass plants you may need to repeat your spray in 2 to 3 weeks. If your crabgrass is very thick with very little good grass and you are planning to seed, you may want to use Roundup to kill everything. The big reason is with the Ortho Weed B Gon MAX you will need to wait 4 weeks after spraying to plant grass seed, however with Roundup you will only to need to wait a week.

Dallisgrass is oftern confused with Crabgrass. Dallisgrass seed head on left and Crabgrass seed head on right.

Dallisgrass is often confused with Crabgrass. Dallisgrass seed head on left and Crabgrass seed head on right.  (click photo to enlarge)

One note:

One weed that gets confused with Crabgrass this time of year is Dallisgrass. Dallisgrass is a perennial grass that is common in the south and surrounding states to the north. Since it is a perennial grass, it comes back every year from roots so a spring applied preventer to take care of annual grasses that grow from seed each year does not work. Often the only choice is to kill this grass with a weed killer like Roundup. The downside is that Roundup will kill all vegetation in the area that you spray, however you can seed that area a week later. You may still have Dallisgrass next year because the plants produced seed all summer. The seed heads provide the best way to identify Crabgrass and Dallisgrass.

Time to Get a Soil Test If You Think Your Lawn Needs Lime

If your grass seems to not be getting much better after a feeding or two, a soil test can help you determine if your soil is acidic. If your soil is acid lime will improve how your grass uses the lawn food you put down. Since fall is a great time to put down lime, doing a soil test now will tell you how much lime your lawn needs.

Fall is a great time to put down lime if a soil test indicates your soil is acidic.

Fall is a great time to put down lime if a soil test indicates your soil is acidic.

Here are answers to the five most asked questions I hear about lime:

Why spread lime on a lawn?

Answer: Lime helps to raise the soil pH level in acidic soils. Soil pH is a measure of how acidic or alkaline your soil is. A pH of 7 is neutral, acidic soil registers below 7, and alkaline soil above 7. Your lawn can tolerate a fairly wide pH range of 5.5 to 7.5, with 6.5 being the ideal pH for growing grass. When your pH is in the ideal range other nutrients in your soil and in the lawn food you spread are more available to your grass plants. When the pH is outside of this ideal range, some of the nutrients get locked up by the soil and your grass can suffer.

What areas of the country usually need lime to raise soil pH?

Answer: Many lawns in the Northeast, Mid-Atlantic, Southeast, and Northwest are growing in native soil that is naturally acidic. The reason I say that all lawns in these areas are not necessarily growing on acidic soil is because soil chemistry can vary from neighborhood to neighborhood. Also, over the years lime may have been spread on a particular lawn on a regular basis raising the soil pH out of the acidic range. For example, when I first tested my Georgia clay soil I found that it was acidic and needed lime. After several years of putting down lime, a soil test showed my soil no longer needed lime. I plan on testing my soil every 2 or 3 years. Although not as common, you can find acidic soil in other parts of the U.S.

How do you figure out the pH of your soil?

Answer: A soil test kit that you buy in your local garden center can be used to measure your soil pH. Most states offer more complete soil testing through their Extension Service. Check for soil testing labs in your state by doing an internet search with your state’s name and the words “soil testing labs”. Other info on these tests provides values for available phosphorus, potassium, micronutrients and organic matter. As a former County Extension Agent, who looked at hundreds of soil test results for home lawns in Virginia, I know that the primary actionable number to look for is soil pH. You can ignore the other measurements if you are feeding your lawn regularly unless one of them shows up as being abnormally low. For example, if you find that phosphorus is low in your soil, you can substitute a Starter Lawn Food for one or more of your feedings during the year to help raise this important nutrient in your soil.

Will I hurt anything if I put down lime on my lawn without going to the trouble of getting a soil test?

Answer: Probably not in areas that are known to have acidic native soils. It is always a good idea to do a soil test first before spreading lime on your lawn. If you live in any area that I mentioned above that has native soils that tend to be acidic, you could spread up to 50 pounds of lime per 1,000 sq. ft. That’s 250 lbs. of lime on a 5,000 sq. ft. lawn. To spread this much lime, you may find you will need to go over your lawn several times with the spreader set at one of the higher settings. You will also find that granulated lime is easier to spread than pulverized or powdered lime.

When is the best time to put lime on a lawn?

Answer: Lime can be applied anytime the soil is not frozen. Fall is a great time to spread lime since the upcoming alternating freezing and thawing of your soil can help to transport lime from the soil surface down to lower parts of the soil.

Why Didn’t Your Crabgrass Preventer Work?

In late summer some folks see crabgrass in their lawn even though they put down a preventer last spring. Their question: “Why didn’t the product work?”

First of all it is good to understand a little bit about how crabgrass grows. Crabgrass is an annual weed that germinates in spring when soil warms up, thrives in summer when it produces seed, and then dies when it frosts in fall. Crabgrass weed preventers kill the new plants as they sprout, not before they sprout. A dormant crabgrass seed can lay in the soil until the conditions are right for growth. If grass is mowed tall (2-1/2 to 3 inches) and the lawn is thick because it has been well fed, crabgrass has a hard time germinating. If the crabgrass preventer is active when it tries to sprout, the preventer will kill it. Crabgrass seeds germinate like waves hitting a beach. The first crabgrass sprouts next to a sidewalk or on a south slope where soil warms first in early spring. The next crabgrass to germinate is in a thin lawn where the sunlight and warmth helps the seed get started. The last crabgrass germinates in mid to late summer in newly exposed soil as grass thins from disease or insects or as the soil surface is broken from weeds being pulled exposing crabgrass seeds to the warm surface.

Crabgrass germinated in this area where the grass was thinned from a lawn fungus problem.  It is easier to kill before it gets big.

Crabgrass germinated in this area where the grass was thinned from a lawn fungus problem. It is easier to kill before it gets big.

Here are the top five reasons that crabgrass preventers may not work as well as expected:

First, if the granules were spread too light or areas were missed in the lawn, prevention will not last as long as expected.

Second, if the product was put down too late, you may see crabgrass growth near a sidewalk or on a south slope where the soil warmed faster in early spring and the seeds started to sprout before application.

Third, if the soil was disturbed after spreading by aeration, dethatching, or pulling weeds, crabgrass seeds will sprout as they are exposed and the crabgrass barrier has been disturbed or broken.

Fourth, the granules will be less effective if the lawn does not receive around a quarter to a half inch of water within 2 to 3 days of application. If there is heavy rainfall to create flooding and soil movement or if the spring/summer rainfall is significantly above normal, the prevention will not be as strong.

And Fifth, if your grass was weakened because it was mowed too short or there was drought in late summer or your lawn got a fungus or insect problem that thinned the grass, crabgrass could germinate if the crabgrass preventer was no longer active. (Crabgrass preventers generally last from 6 weeks to 4 months depending on the product used. Scotts Halts products last up to 4 months.)

There are two reasons Scotts Halts and Scotts Turf Builder with Halts work better than other brands. These products contain one of the top rated ingredients for preventing crabgrass and the granules are smaller to provide better coverage of each square inch of lawn surface. Competitive products that do not work as well use larger particles and a lower rated, cheaper ingredient to prevent crabgrass.

If you have crabgrass in your lawn now, you can spray it with Ortho Weed B Gon MAX plus Crabgrass Killer.

When Does a Lawn Need Aeration?

When a lawn has more than a half inch of thatch; water, air and nutrients may not be getting down to the roots. The tell-tale sign to look for is if your lawn does not really turn a healthy green after feeding. You can check your thatch layer thickness by removing a plug of grass, soil and all, and measuring the brown thatch layer between the green growth and soil layer. If thatch is greater than a half inch, consider aeration or dethatching.

This illustration shows that root depth is restricted by both compacted soil (far left) and too much thatch (2nd from left). Feed your lawn after aerating. The result is improved root growth as shown in the far right illustration.

This illustration shows that root depth is restricted by both compacted soil (far left) and too much thatch (2nd from left). Feed your lawn after aerating. The result is improved root growth as shown in the far right illustration.

I recommend lawn aeration using a machine that removes cores from your lawn in cases where you want to improve your existing lawn without tearing it up. A dethatching machine may be a better choice if you are trying to remove dead grass and thatch to expose soil so new grass seeds have a better chance of getting started.

Since fall is a great time to aerate cool-season grasses, this is a very timely topic for those with bluegrass, ryegrass, fescue and bentgrass. The best time to aerate warm-season grasses is early summer, however if you have a severe thatch problem in your Bermuda, Zoysia or St. Augustinegrass you can aerate anytime your lawn is actively growing.

A second reason to aerate a lawn is if the soil is compacted. You can tell if your soil is compacted if it is difficult to stick a screwdriver into your soil even when it is wet. When a lawn gets a lot of use (like you get with athletic fields or golf courses) the soil can get packed down and compacted, restricting the flow of water and nutrients. There are some tell-tale signs that your lawn may be compacted. Poor drainage is one. If water pools up on your lawn or runs off instead of soaking in, it could be because the soil is compacted. Lawns that look worn-out are often because of compacted soil.

Aerate your lawn by making individual holes around three quarters of an inch in diameter, three inches deep, and no more than 3 inches apart. This is best done with an aerating machine that removes plugs of soil, NOT the kind that just punches spike holes in the lawn. Soil should be moist enough for the machine to remove plugs that are around 3 inches long. Follow up the aeration with a feeding of Scotts Turf Builder or Scotts Natural Lawn Food.

You can rent an aeration machine at many Home Centers and Hardware stores, however since they are quite heavy, you may find it best to hire a professional such as Scotts Lawn Care Service (for more info, give them a call at 1-888-736-3478). If you decide to hire a service, you should schedule this ASAP as they get booked up pretty fast this time of year.

Oh, here's some good news: after aerating, you can leave the plugs on your lawn.

Oh, here’s some good news: after aerating, you can leave the plugs on your lawn.

Plant Veggies Now for Fall

Rita and I almost get as excited about our fall vegetable garden as we do when planting our spring garden. The big reason is we eat a big salad almost every night and there is nothing like picking fresh lettuce, spinach and kale leaves just minutes before dinner.

Spinach, Kale, Lettuce, Swiss Chard deck planters provide daily pickings for our salads.

Spinach, Kale, Lettuce, Swiss Chard deck planters provide daily pickings for our salads. (click photo to enlarge)

There are many vegetables that you can plant now for harvest this fall. You may have space in your garden where some of your early summer vegetables have finished doing their thing. This will give you room to plant lettuce, spinach, turnips, mustard, kale, collards, and other cool weather veggies that are not really bothered by frost. Some of you in Florida, Texas, Arizona and other southern states with mild winters also have the opportunity to plant other vegetables including squash, cucumber, tomato and many others. And do not forget to plant a few containers with lettuce, spinach or a good mesclun mix to set around your deck or patio. When planting in your garden, replenish your soil by mixing in an inch or two of Miracle-Gro Organic Choice Garden Soil. If your soil is especially sandy, you should switch to Miracle-Gro Moisture Control Garden Soil. When planting in containers, start with a fresh bag of Miracle-Gro Moisture Control Potting Mix. (Garden Soil is for mixing with native soil in the ground while Potting Mix is for containers and hanging baskets.)

A vegetable that you can plant now for harvest next year is garlic. Here is a link to one of the many garlic sources where we have found many great varieties: Click here to visit the Territorial Seed site where you will find over 30 varieties of garlic.

Garlic we harvested in summer that we planted the previous fall.

Garlic we harvested in summer that we planted the previous fall.

Get your kids involved in this activity to help them appreciate the wonders of nature! You may even find they will enjoy eating vegetables that they helped you grow!

How to Kill and Replace Your Lawn

This “kill and replace” strategy is for lawns troubled by the kind of grassy weeds you can’t kill without killing your good grass and for lawns you are fighting a constant battle with lawn diseases. We are approaching the best time of year to renovate cool-season grass lawns (like Bluegrass, Ryegrass and Fescue). Note: warm-season grass lawns (like Bermuda, Zoysia, St. Augustine and Centipede) are best started in late spring.

Starting over allows you to use today’s top-of-the-line seed blends that do a better job of tolerating drought and attacks by insects or disease. Starting over may be the best way to get rid of perennial grassy weeds such as Dallisgrass, Nimblewill, Bentgrass, Orchardgrass, Tall Fescue clumps, or Quackgrass that you can’t kill without killing your good grass too.

This 20 year old lawn contains weak grass varieties making it a good candidate for the "Kill and Replace" strategy.

This 20 year old lawn contains weak grass varieties making it a good candidate for the “Kill and Replace” strategy.  (click photo to enlarge)

Here are the steps to renovate a lawn by killing the existing grass and establishing a new lawn:

Step 1: Mid-August, spray your bad lawn area with Roundup (click here for more info). Be sure to use regular Roundup and not one of the special Roundup products that provide longer term weed prevention.

Step 2: About a week later do a repeat spray of Roundup on any areas you missed.

Step 3: A week later mow your dead grass as short as possible removing the clippings as you mow. Rent a Dethatcher (also known as a Power Rake) and run it over the dead lawn in two directions. Set the machine low enough so that the blades are touching the soil. Rake up the dead grass and add Scotts Turf Builder Lawn Soil (click here for more info) to any low spots. If you now have mostly bare soil with the top inch or so broken up you could skip the next Slit-Seeder step and broadcast your seed using a Scotts Spreader.

If you have more dead grass than bare soil, rent a Slit-Seeder to plant the grass seed through the dead lawn. with Scotts best seed blend for your situation.

Step 4: It is now early September… a great time to plant bluegrass, ryegrass and fescue. First you select the best seed blend for your situation. The best Scotts grass seed blends are in the Scotts Turf Builder Grass Seed line (click here for more info). Choose a blend rated for Sun, Sun/Shade, Dense Shade, High Traffic, Heat-Tolerance or one of the other special blends. I am a big fan of Scotts Turf Builder Grass Seed Heat-Tolerant Blue Mix.

Step 5: Spread Scotts Starter Food for New Grass (click here for more info) the same day you seed.

Step 6: Water a couple of times a day for several weeks.

Step 7: Mow your new lawn when it is tall enough to cut with the height set at around 2-1/2 inches.

Step 8: About a month after seeding, feed your new lawn with Scotts Turf Builder Lawn Food (click here for more info). Do not use any weed controls on your new lawn until your new grass has been mowed 4 times.

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