Think about weeds and what they need. They need water, nutrition, and sunlight to thrive. Since those are all the same things the plants need to thrive, as we tend to our gardens trying to create the perfect home for our plants, we are at the same time creating the perfect home for weeds. Water and nutrition are a necessity for our garden and even without our intervention there is plenty of nutrition in the soil and in most areas, water comes naturally through rainfall. So, the only thing left that we can control is the amount of sunlight that we allow the weeds to receive.
Bingo! That’s it. We can control the weeds simply by controlling the amount of sunlight that we allow them to receive. That’s great if the bed is to be mulched with material that will block the sunlight. If for instance you don’t want to mulch your garden, then you must use other measures to control the weeds. But let’s first consider ways to block the sunlight.
Two to three inches of mulch does a pretty good job of blocking sunlight. But the secret to using mulch to control weeds is to get the garden almost 100% weed free before you apply the mulch. That’s a mistake that a lot of people make with their gardens. They never get ahead of the weeds. I am growing thousands of plants in beds and it’s too much area to mulch so I use pre-emergent herbicides and I’ll explain that in a minute. But even with the pre-emergent herbicides I still get weeds. And if I don’t stay on top of it, I have a mess on my hands.
It is best to get the situation under control, so I go through a bed and pull all the weeds. In the aisles where I can run a rototiller, I will leave a weed if it less than 2″ tall. But I pull any weeds larger than that because I want them eliminated. After I pull the larger weeds, I go through the bed with my hoe and loosen the soil between the plants and remove any tiny weeds that I might have missed when hand pulling weeds. Once I’m done hoeing (is that a word?) I rototill the aisles and when I’m done the weeds are gone. Right after this I apply a good pre-emergent herbicide that will last for several months.
Using Newspaper to Control Weeds
It is important to eliminate the existing weeds before you do anything else. If you are going to mulch, put down newspaper 8 or 9 inches thick then cover it with mulch. The newspaper will blow around easily so lay the newspaper down as you mulch. Don’t worry about the ink on the newspaper, it’s all soy based these days and will not harm your plants. Now if you want to use a pre-emergent herbicide like Preen you can apply it after you mulch but read the label carefully. They might suggest working it into the soil. I don’t think so, but if that’s the case you can just apply it before you put down the newspaper.
Follow These Steps
- Weed the bed until every weed is gone.
- Lay down newspaper or brown paper grocery bags. Newspaper should be at least 5 pages thick, but 8 or 9 pages thick is better.
- Put down 2 to 3 inches of mulch.
- Apply a pre-emergent herbicide like Preen.
If you do a really good job weeding, put down the newspaper and the mulch, you probably don’t need the pre-emergent herbicide for a while. Pre-emergent herbicides prevent weed seeds from germinating. When applied they create a vapor barrier that nips the tiny weed sprouts as soon as they germinate. If you don’t want to use chemicals, you’ll get good results without them if you stay on top of the situation.
The Biggest Secret of All
You must stay on top of the situation. Weeding is not a once-a-year job. It’s something you do several times a week as you enjoy your gardens. Now when I say several times a week, I don’t mean get out the gloves, the bucket, the knee pad, the dirty jeans and get down and dirty and start pulling weeds. But as you casually stroll through your yard reach down and pull the weeds you see. If you do this, you will not have any weeds in your yard and you won’t have to dedicate a day to pulling weeds for a long, long time.
What if the Area is Too Large to use Newspaper?
If you have a large area that is full of weeds and grass, and you want it to be a really nice garden you can make the area weed free simply by tilling the soil or turning the soil. All you need to do is till the soil, tilling in all the weeds and grass. Wait about 5 days in warm weather then till again. Just keep repeating this process over a period of several weeks until you see absolutely no sign of weeds.
This is what happens. You till the soil and some of the weeds and grass that you tilled in will be near the surface. The hot sun will bake them, drying them out until they are no longer viable. Other weed and grass plants will not be near the surface and will be suffocated being under the soil. When you till again you are once again exposing viable weed and grass plants to the surface and the sun. At the same time, you are pulverizing the weeds and grass that are not exposed to the surface.
As you are doing this there is a third process that is taking place but going unnoticed. The soil is full of weed seed. Weed seeds often germinate in a matter of days. After the first tilling there are thousands of weed seeds that are trying to germinate. When you do the second tilling you are literally cutting them off at the pass and stopping them in mid germination. Once the seed germinates and is terminated by you through this tilling process, it is no longer viable. Several days later you till again and thousands more weed seeds are rendered no longer viable. The more times you till the soil the more weed seeds you are eliminating.
It would be foolish to think that we could eliminate all the weed seeds from the soil. They blow in by the thousands. Think about your vegetable garden. You don’t want to use chemicals in your garden, but if you can keep it tilled or cultivated on a regular basis you can keep the weeds at bay that way.
Rule #1 is to read the labels and wear protective clothing. Many people reading this article think that nobody should be using chemicals to control weeds. I love that idea, but I’ve pretty much done nothing in my life that wasn’t somehow gardening related, and I know the realty of people not using chemicals. We want nice green, weed free lawns so we apply chemicals. We don’t want the Japanese Beetles to eat all the leaves from our roses, so we apply chemicals. The garden stores have a complete aisle of gardening chemicals. Therefore, as a garden writer I must address the subject.
As I’ve already mentioned in this article, I use chemicals to control weeds. Basically, there are two kinds of chemicals for controlling weeds and unwanted grasses. There are pre-emergent herbicides that have already been mentioned in this article and post emergent herbicides.
Pre-emergent herbicides are designed to do one thing and only one thing and that’s to prevent weed seeds from germinating. They have absolutely no control over weeds that are already growing. Post emergent herbicides are designed to kill weeds and unwanted grasses that are already growing. For the most part when you are buying a post emergent herbicide for home use you are buying what is called a non-selective herbicide unless you are buying something for your lawn.
The weed and feed products that you use on your lawn are “selective” herbicides. In other words, they will kill broad leaf weeds like dandelions, but they won’t kill the grass that you are trying to make prettier. But if you accidentally get them on the plants in your flower beds, they will see those plants as broadleaf and could kill those as well. They are designed to not harm anything in the grass family.
The most common “non-selective” herbicides contain glyphosate which is a non-selective herbicide that will kill weeds, grasses, and other plants that it touches. I use a generic brand to spray the weeds on the edges of the nursery. I pretty much use it any place where there are weeds and grasses that I want to eliminate, and I can spray and not get the herbicide on other plants. For instance, when I get ready to landscape an area, I will first mark out the beds with orange spray paint, then spray all weeds and grasses inside of the beds before I do anything else. That saves me having to dig them out and it is 100% effective at eliminating them, so they don’t come back and haunt me.
Once you spray weeds or grasses with a glyphosate product you must leave them alone giving the herbicide a chance to work. Glyphosate is sprayed on the foliage of the leaves and grasses that you want to eliminate. More is not better. All you need to do when applying these non-selective herbicides is wet the foliage. If you spray to the point that the product is running off the leaves you are apply too much. So just wet the foliage and then wait. The way that Glyphosate works is it is absorbed by the plant and the chemical is trans-located through the plant. That’s why when it’s first applied you won’t see any immediate sign of the weeds dying. You must give the chemical at least 72 hours to do its job. After 72 hours the weeds and grasses won’t look dead, but for the most part they are. After 72 hours you can dig and chop, till the weeds in etc. It doesn’t matter, if you’ve applied the product correctly and given it time to work, those weeds and grass plants are dead.
Do the Chemicals Linger in the Soil?
People who are very committed to nobody using chemicals will tell you that it does linger in the soil. People like me who use it on a regular basis and have been doing so for many, many years will tell you that it does not linger in the soil. I believe the manufacture claims that it does not linger in the soil, but I suggest you research that on your own if you are concerned. All I know is that I can spray a bed or a section of my lawn with glyphosate and three days later sow grass seed or install plants and the plants do fantastic and the grass seed grows just fine.
Tips for Applying Post Emergent Herbicides
Read the label and take all the recommended precautions. When you apply it, you should have a small one-gallon sprayer that is clearly marked with a permanent marker, “for weed spray only”. Never use the same sprayer for any other task around your house.
When you spray you must be careful to not allow the spray to drift or to get any over-spray on the plants you want to keep. The nozzle on the sprayer is adjustable. You can adjust the spray from a long stream to a very fine mist. The very fine mist is the most likely to drift. I do two things when I spray a non-selective herbicide. One, I only pump the sprayer just enough to deliver the product. The lower the pressure the less of a mist you will have. It takes pressure to create that fine mist, and I don’t want a fine mist. I only pump the sprayer just enough to make the product come out the nozzle. The second thing I do is adjust the nozzle, so the spray pattern is not a steady stream, but a heavier spray pattern and not a fine mist. The heavier the spray pattern the larger the spray droplets and the lower the chance that they’ll be carried by the wind.
Never spray a non-selective herbicide on a windy day. Wait for nice calm day to do your spraying. Keep in mind, a nonselective herbicide will get rid of the weeds that you have today, but it’s a very short lived, step one. Three days after you spray the weeds and grasses that you want to get rid of, you need to employ one of these other strategies to keep that area weed free. Mike McGroarty is the owner of McGroarty Enterprises and the author of several books. You can visit his website at Freeplants.com and read his blog at Mikesbackyardnursery.com.