Treating a lawn with crabgrass control fertilizer
Know your enemy
Crabgrass is everywhere come springtime. Probably even in your own lawn. In order to effectively combat crabgrass, you first must understand it. Crabgrass is an annual grass that begins to appear in early spring. It's growth habit tends to be somewhat flat and circular. Although it can grow in a more tufted form as well. The long stems spread out quickly, cover and choke out any existing turf or weeds. The multitude of long, narrow spikes at the top of the main stems carry tons of seeds. If left alone, crabgrass will quickly and easily take over an area. Being an annual, it will die out by the end of the season, but it will have laid thousands of seeds ready to go next year. Luckily, modern science has found a way to keep this from happening.
Post emergent herbicides
Modern science has developed many herbicides that can be used to fight off this ugly, invasive grass. While there are many varieties available solely through commercial means, the average Joe has some good choices available to him/her as well. There are two versions that herbicides come in. They are either liquid (post emergent) or granular (pre-emergent). Both are popular and effective. However, in my opinion, pre-emergent is the best means to aim for.
Pre-emergent granular herbicides
- Pendimethalin - The active ingredient in Scotts "Halts" brand of crabgrass control fertilizer
- Dithiopyr - The active ingredient in many generic crabgrass control fertilizers
Both work very well when applied correctly. While I am used to using commercial grade fertilizers, I would recommend using the Scotts brand of fertilizer for your use. The generic versions are less expensive and are effective, but Scotts is probably the best offering on the retail market.
Post emergent liquid herbicide
- Quinclorac - This is the most common crabgrass killer for liquid crabgrass killer offered on the retail market.
While effective, my personal experience has been that when using a liquid herbicide that is offered in retail, multiple applications may be needed.
Illinois Soil Temperature
- Illinois State Water Survey - Water and Atmospheric Resources Monitoring Program - Soil Maps, Univer
The Water and Atmospheric Resources Monitoring Program (WARM for short) was initiated in the late 1980s to coordinate monitoring of numerous ISWS data collection efforts. WARM is presently expanding it's online efforts to include many new types of da
Executing the battle plan
When you choose to utilize a pre-emergent herbicide, there is a key element to successful crabgrass control. Timing. Timing is key. While all the products tell you a time frame of the early months of spring, that really isn't a very accurate or helpful instruction. You want to neither apply too early or too late. Applying in the early spring before the temps reach the 80's is just too generalized to be effective. Instead, pay attention to soil temperature. I've included a link for you Illinoisans for soil temperature. For the rest, contact your state college extension office. Crabgrass seeds germinate when the soil temperature is consistently between 55-60 degrees 2 inches below the soil surface for several days. When you see this, apply. This way you are ensured to get a jump on crabgrass before it gets a jump on you.
If for whatever reason you might miss this narrow window, your second line of defense is liquid herbicide. This can be applied anytime the air temperature is below 80 degrees. Applying at temperatures above 80 will cause damage to your lawn. You will see "burn" spots in your desired turf that may not recover.
Always follow the precautions listed on the labels of the products you use. They are generally safe if used properly, but improperly, they can be harmful. With granular fertilizers, make sure you adhere to the proper spreader settings. Applying too little is ineffective and too much is harmful to your lawn and your pocketbook. When fertilizing, I recommend the use of a broadcast spreader. They apply a more even coverage and are less likely to "stripe" your lawn. Also, establish a pattern of application. I recommend applying a "border" and then crossing the interior in roughly 3 foot intervals. This ensures an even coverage eliminating a striping effect or burn spots. Always close the spreader opening when making a direction change so as to prevent any spillage. Once again, remember to never apply liquid herbicide in temperatures above 80 degrees. Applying in drought conditions is also not a good idea.