Controlling Weeds in your lawn is one of the most important thing to do to keep a great looking lawn. A lawn that is clean of weeds looks far better than one that has weeds standing up. A lawn that has no weeds will look like it has just been mowed even 3 or 4 days after it has been mowed. Have you noticed that when you have Dandelions in the lawn that you can cut the grass today, and tomorrow the lawn looks like it needs to be cut again because the weeds are standing up 4 or 5" above the grass. A clean lawn looks smooth for days after it has been cut, so you will mow less. A weed free lawn will be thicker with your desirable grass since there will be less competition from the weeds. Your fertilizer and lime and other products you put products, not the weeds. Now we have the benefits of keeping a weed free lawn, let's look at how to do it.
Weeds are broken up into two main types, broad leafed weeds and grassy type weeds, there is a third type or in between type, sedges- purple nutsedge and yellow nutsedge. They are neither grasses or broad leaves. Your weed control strategy needs to begin with knowing what types of weeds you have in your lawn. You don't need to know exactly every variety of weed but at least a general knowledge of what you have out there. Most all lawns are going to have the usual dandelions, crabgrass, plantain, thistle, spurge, oxalis, and a few others that are common but you may have never known their name. A simple way of doing weed control is to follow a prescribed program that is used in your area and covering all of your weeds that may be there. For example Scott's has a pretty good 4 step program you can go to Lowe's or other home centers and buy. It will come in bags marked step 1, step 2, etc. This makes it fairly simple.
Most weed control programs start with a basic 4 step program
1) applied in Spring, 30 days prior to when you expect the target weeds to germinate. So in the far south you may need to apply in Feb. in the North it could be April. 2) applied some 60 days later this will be a fertilizer / broad leaf weed control combination product ,if you are putting down bagged material. If you are going to be spraying your weed control products you will be putting down just fertilizer in granule form. It depends on your equipment and how you are able to put the product down. 3) another application of fertilizer and some products will contain an insecticide, most of the time no weed control will be used here. 4) a winterizer formula, usually a high potash formula and broad leaf weed control again.
These four steps are a basic program that several fertilizer formulators will provide to make it easy for a homeowner to apply a weed control program to their lawn. You can get more advanced by using liquid weed control products and using granule fertilizer, this gives you the flexibility to taylor make your weed control program to your lawn. One disadvantage of using the bagged products is that they are mixed one way by each company. What you use is the same thing someone in Ohio is using while you may live in California, makes sense to use something that will take care of your weeds, in your lawn, in your state doesn't it?
The two main types of weed control are Pre-emergent, meaning before the weed comes up. And Post emergent, meaning after the weed comes up. Everyone has heard the term "crabgrass preventer". This is a pre-emergent herbicide. To kill dandelions, plantain and several other broad leaf weeds you will use a post emergent, this will be put down after the weeds have come up, and usually the second application of the program. The pre-emergent will prevent several weeds from ever coming up so you will not have as many during the second application as you would have, if not used. The lawn will look better if the weeds never come up than if they come up and then you kill them. Still there is a need for both types of weed control. That's why there is a complete weed control program that we use, sometimes as many as 8 applications during the year. It just depends on what level of control you want and the look you want in your lawn. And of course where you live in the US matters too. In the far south the growing season is longer so there is an opportunity to have a good looking lawn for more of the year requiring more applications.
Please be aware that chemicals can be dangerous, if you are not comfortable using them, then call a licensed professional applicator to do the job for you. Some chemicals in their concentrated form can kill a human if injested. Some chemicals are very concentrated and are more dangerous, the chemicals available to the homeowner aren't as strong as those used by professionals and are somewhat safer, although still dangerous.
The pre-emergent chemicals are used primarily in the spring, but we have used them several times in the early summer and in the fall. A good pre-emergent program will stop those weeds from coming up making your lawn look better through the year and you will have less weeds to kill after they are already up. But, no matter what you do you will still have some weeds that escape the pre emergent applications, these you will need to go after with the post emergent weed killers. Some will debate which is better, granules or liquid that you spray. I prefer the liquids, they go to work faster and in the commercial weed control business they are the standard. Homeowners mostly prefer the granule products since all you need to put them down is a spreader. Applying liquid requires a sprayer and the knowledge to calibrate that sprayer son you put down the correct amount. You cannot simply put 20 oz of weed killer into a sprayer, mix some water with it and start spraying. The container will have a label, instructions. READ the instructions and follow them. Do not assume that if one ounce is good, two is better, you may kill your entire lawn. For this reason most people will use the granules. For granular application you still have to know how large your property is, and what setting to put your spreader on. The bag of granular weed killer will also have a label with instructions, follow them. They even make it easier on some bags they say "this bag will cover XXXX sq ft of lawn". So you need to know how large the lawn is. If you buy one bag and spread it over the lawn and it's not enough, you won't kill anything, if you buy 4 bags when you only needed 2 you will kill the weeds, the lawn, the cat, dog, maybe you. READ the label and follow it. For most granules the bag will have a listing on the bag for most popular brands of cyclone type spreaders. The chart will say to set your spreader on XX opening for this product to apply at the proper rate. This is assuming that you will apply evenly, not missing spots, and not overlapping too much. If you make a pass, then turn around coming back across the lawn and overlap by 1/2, you will use twice as much material as your supposed to. This will also cause "stripes" in the lawn, dark green and light green. This is from more fertilizer in one spot than in another, it's a common problem. Using a liquid sprayer for large areas is much more difficult to calibrate. The small 15 gallon tow behind type sprayers are becoming very popular. They work great if used properly. If you just start spraying without knowing the calibration, your asking for trouble. Calibrating the sprayer isn't too hard if you understand it. A simple way to tell how much it puts out is to fill it with water, set your mower on a fixed speed, kind of slow but not crawling, and see how far it goes before you run out of water. You can change the amount of water or your speed until you have figured out how fast you need to go to use up one tank full over the whole lawn. Then you read your label. Suppose it says to use 2 oz per thousand square feet, you need to know exactly the square feet in the lawn your going to spray then you can mix your chemicals properly. If you have 10,000 sq. ft of lawn area you would need 20 oz of chemical mixed into the tank that you have determined will cover all of the lawn. Now the challenge is to spray the lawn without overlapping and covering some areas twice or three times. If your using a lawn tractor to tow a sprayer, think of the sprayer as a spray painter, and you only want to paint each area once. Twice and you may kill your lawn, you have to be precise. A remote switch located on your tractor is very handy to turn off the sprayer where you have to overlap at the end of the lawn when your turning around and getting lined up to go again, this way you aren't sitting still with the sprayer running. Remember, if you stop the tractor turn the sprayer off quickly, it's better to turn it off before you stop the tractor, that way you don't spray in one spot. You can apply 5, 6 or even 10 times the required amount in one area if you stop and the sprayer is still spraying. There will for sure be a dead spot there. As you can see, it's just a little more involved than just getting some weed killer and spraying. So again, if your not comfortable doing this, hire it done. Out of all the Lawn and Landscape maintenance items, this is one you don't want to mess up on. Having a disaster on this is going to cost you a year in replanting, re-sodding or however you established your lawn in the first place. Ask yourself is it worth it?
IF you have a very small lawn and can do your spraying with a hand held sprayer, it will be much easier as long as you follow directions and don't use too much solution in one spot. Spraying by hand is easy, but don't mix up your solution too heavy or too strong, if you spray a large amount in one spot you will kill the weeds and the grass and have dead spots over the lawn. Usually you will spray with a hand sprayer to the point of wetting the leaf, not so it puddles up and runs off. Follow instructions on the label and it will tell you how to mix and how much to spray. If you have any questions we will be happy to try to answer them for you, just email them to us Weed Control Questions
We know this isn't all the information you need to be an expert in weed control, but it is only meant to be a overview to let you know what's involved so you can choose to learn more or hire someone to do it for you.