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Rid Crabgrass From Your Lawn

          Simple techniques that will help you prevent and kill crabgrass.

Let’s Talk A Moment About Crabgrass

Crabgrass is actually an annual weed that takes over in any spots that are bare. It is very green and attractive to the untrained eye but for those of us who know it is a enemy of the lawn. It will prevent you from the main goal of having the best lawn in the neiborhood. It is not specific to any type of lawn. It can exist and take over if you let it.


What Is The Germination Time Of Crabgrass?

The ideal germination time for crabgrass is once the soil temperature, not the air temperature, rise above 55-60 degrees. You can actually start to see them begin to sprout out at about 70 degrees. When it gets hotter than 75-80 degrees germination ceases and you will then only see the massive growth habit.

The seeds are sowed over the summer and fall and remain in the soil over the winter baking its bed. When spring arrives and the soil temperatures begin to rise germination begins as we discussed earlierMost homeowners won’t see this grow take place until it is too late. The summer rain and heat will make this weed grow at a speed you have never seen. These are the seeds growing that were laid last year and maturing. Those with cool season grasses wil suffer the most intrusion as the fescues and other cool season grasses do not have a spreading habit. Therefore, crabgrass outcompetes the lawn grass and takes over.


Identifying Crabgrass.

Crabgrass can sometimes be misidentified as tall fescue.  They are similar as in that they both have a broadleaf but if you look closer you will see that crabgrass has crab like legs that radiate from the center of the clump. Where a fescue shoots up from the clump. It has a light green color and if left unattended can get way out of control.


How Is Crabgrass Spread?

Well, this is a common question so I will answer this in the post. Crabgrass seedlings are spread in many natural ways but the main way you spread it in your own lawn is by mowing your lawn. When you mow and discharge your grass out the side of the lawnmower then you are spreading the seeds through the air and where they land can be any where. They can land in your lawn or even in your landscape beds. I have even seen people having a hard time controlling them in their vegetable gardens.

Another method of spreading crabgrass is cutting wet grass. The lawnmower picks up the wet grass with seeds and disperses the seedlings that were on the blade and under the deck to other parts of your lawn. I have seen beautiful lawns turn into dwellings that were traced backed to this meathod. The lawn care companies cut so many lawns a day and by the time they reach you their deck and blade are full of seeds from all kinds of weeds and other grasses. As a home owner I wash my deck every time if I cut wet grass. That way I don’t spread the weeds throughout the lawn.


 Prevention of Crabgrass

Pre-emergent herbicides can be sorely misused and for that reason most homeowners give up on crabgrass prevention. In early spring most of you will run out to the nearest Lowes or Home depot and grab a bag of weed and feed. When I started out learning about lawns this was my go to. But as I advanced into lawn care I saw that this was not just feeding the grass but the weeds to. Yes, it would prevent some but not crabgrass. Crabgrass has to be handled with specific types of chemicals that I will share with you.

First, you should know that crabgrass pre-emergent must be applied at the right soil temperature. When you notice a consistence soil temperature of 50 degrees then apply your first dose of pre-emergent. Read the instruction on the back to make sure you are delivering the right amount vs the size of your lawn.  Then a second application about 6-7 weeks later when temperatures are on the rise toward 65-70 degrees.

Below are what the pros use to keep the crabgrass out of their lawn.


1. Dimension: This is a very well-known product that has been working for the professionals for years now. If you are looking for a good weed and feed product that will attack the crabgrass seedlings then Lesco crabgrass pre-emergent 19-0-7. Another great benefit to this product is it’s weed control. Not only will it provide control over crabgrass but it also will kill off over 45 different weeds and unwanted grasses.

2. Prodiamine: This is also a great product in the fight against crabgrass. If you see products that have Barricade as their main ingredients than this is the active chemical against weeds. This is also available as a weed and feed application but you may have to visit your Feed and Seed store.

The two above are the best pre-emergent to use against crabgrass and as a lawn care professional that is all I would use. That said there are programs used by top lawn care companies that use a chemical called pendimethalin. This is a fine product but you may see yourself adding more to the lawn than you would if you used one of the products mentioned above.

Whatever chemical you decide to use make sure you are applying them during the correct soil temperatures and you should have success.


Killing Crabgrass

If you are passed the crabgrass pre-emergent stage and you just need to eradicate this weed then a liquid form may be in your best interest. This will be for spots that were bare and grass was outcompeted by weeds. When using liquid products I always mix them with a surfactant. This will help the chemical stick to the weed leaves and be more effective.


1. Spectracide- If you have an area that has already established crabgrass then this product would be where I would start. Spectracide weed stop for lawns will kill crabgrass to the root in just 5 hours and will not harm the surrounding grass.


2. Tenacity- What a great product for just knocking out a clump here and there. Also lawn safe tenacity will need to be mixed in a sprayer before applying. Most of the products used to kill crabgrass cannot be applied during new grass seedings but tenacity is not harmful to the new seedlings.

3. Ortho weed B Gon – This is by far one of the most common weed killing liquid on the shelf that will not kill your lawn when applied.

As a rule of thumb I always walk my lawn looking for weeds before they get out of control.


Digging In

As I do with dandelions sometimes crabgrass has to be dug up as well. I remember coming home after work one day and my wife had a shovel. I was thinking to myself what plant is she digging up now. As I got closer to the area she was in she was using the shovel to remove this massive clump of crabgrass. After she had dug this lawn cancer out of the ground she was sweating and had dirt all over her. The root structures on this thing was amazing. I use to be in the medical field so I have seen what cancer looks like after it is removed from the body. This had a similar look and I tell you that is the day I took crabgrass serious.


Healthy Lawn

Maintaining a healthy lawn is not easy but for great results you have to stay on top of it.  A lawn care guide will help you in many ways to get the lawn you want. Mowing at a three inch height will help prevent the crabgrass seedings from germinating. They are shaded by the tall grass so sun can’t reach the seedling.

Staying on top of bare spots and worn areas in your lawn will go a long way it maintaining a healthy lawn for you and your neighbors to enjoy!


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