weed killers, herbicides, weed control

In a landscape setting, that is, your lawn, your beds, maybe even your vegetable garden, chemical herbicides can be used to control weeds. Proper use of herbicides can make your 'weed control' life a little easier, but you should always use products exactly as specified. More is NOT better. All herbicides interfere in some fashion with a plants ability to grow, usually either by interfering with the photosynthesis process or by curbing root growth.

There are a couple of things you need to determine before you buy or apply any herbicide. First determine just what it is you are trying to eliminate, then can you determine which product is best to use. You need to match the type and kind of herbicide with the type and kind of weeds that you want to eliminate. You also need to know if any herbicides that are applied will affect any plants in the surrounding area. Read the labels or ask professional advise if you're not sure.

Pre emergent herbicides are applied 'before' (pre) the weed begins to grow. That is, they prevent the seeds from germinating into a new plant.

The most common post emergent herbicides on the market today contain 'glyphosphate.' These products are sprayed directly on the foliage of growing, healthy weeds. They begin to work as soon as the chemical is absorbed into the plants system, although it may take as long as a week or two, before the plant totally dies. You will notice the tops of the weeds turning brown, but the weed is not totally dead, until the roots are killed, as well.

If you add a surfactant or spreader-sticker as it is sometimes called, to your spray mix, it will adhere to the leaves more evenly and help the product along. I add this faithfully, more so as a habit, as it is only really necessary for plants with shiny, smooth foliage where the chemical may runoff more readily or when there might be a chance of rain before the chemical dries. When added to your mix, not only will it do what I just mentioned, but it prevents waste of the product. I, also add a touch of liquid fertilizer in the tank mix when I spray. Don't laugh it works! You will see why when you read on.

Glyphosphate based weed killers may take as long as a week to ten days before you notice any kind of visual results, and you may think that it is not working, but it is. Spraying glyphosphate based weed killers on grass-like weeds and on lawn grasses will show the quickest results. Soft stemmed, shallow rooted weeds and grasses are usually the easiest kinds of vegetation to spray and kill with these products. But it also works on woody stemmed, and/or deep rooted weeds and vegetation, like briars, poison ivy and thistle, it just may take longer, and may even require another spray application, before they are totally eliminated.

Several common mistakes that people make when using glyphosphate based products are due to the fact that they do not understand how these products work.

First of all, there is an optimum foliage height at which any vegetation that you are trying to kill should be at and that is somewhere between 4"-12". Spraying at this recommended height will assure that enough of the chemical is absorbed into the plant and its roots. This is not to say that it won't kill anything shorter or taller than this, only that these general heights are recommended. If the vegetation is too short, allow it grow somewhat if possible, if it is too tall cut it back to the proper height first. If the vegetation is woody, cut it back to the ground and allow a flush of new growth to reach the proper height before spraying.

This brings us to the second mistake people often make. Spraying when the temperature and growth cycle are less than ideal. Spraying to kill weeds, when you happen to have the time, doesn't always yield the best results, because the vegetation must also be actively growing. This will not only assure a guaranteed kill, but a quick one. I know for a fact ,that there are people out there who think that these sprays aren't working quickly enough or who think that they are not working at all and continue with repeated sprays to the point of saturation and runoff. This is a waste of the product. There isn't any need to spray to the point of runoff. What you need to understand is, that there is also an optimum temperature at which all plants actively grow and/ or slow down their metabolic process. Haven't you ever noticed how in the Spring of the year, the grass in your lawn just seems to grow thick and lush and the darn mower won't start, and as soon as the heat of Summer is here the grass growing slows down, the mower runs great. When the cooler temperatures of early Fall arrive the grass begins to grow lush again. Well this is the answer, certain plants, and weeds, grow better during different seasons, hot and cool. If you're set on spraying off weeds, or grass, in mid-summer, and the conditions aren't ideal, there is no need to fret, you just need to trick the plant into growing. Go ahead and spray, wait a day and then go out and water the area or even fertilize it. What will happen is simple. Your plants will begin to grow and as they do they will absorb more and more of the chemical into their systems until they are dead. Aren't we nasty!

A frequently asked question, for those concerned with chemical use, is… what happens to the extra product that misses the plants/weeds and hits the soil surface? Glyphosphate based products work as a result of absorption into the foliage and internal system of the plants, they only kill plants they are sprayed on. When it comes into direct contact with the soil, glyphoshate is readily broken down by soil microorganisms and will not sterilize or contaminate the soil as some weed killing products do. In fact, as it breaks down in the soil, it nourishes soil bacteria.

This is one big difference and benefit in using glyphosphate based products… they do not sterilize the soil. Careful selection of herbicide products must be made because there are products that do prevent anything and everything from growing in soil that has been treated. Great care must be taken when using these types of soil sterilizing products.

A third mistake people tend to make, and this is a biggy, is that they jump the gun. Just because the top may look dead, doesn't mean that the bottom is. Remember some plants like pigweed, thistle and crownvetch ( by the way I consider this a first class weed) have extensive deep root systems. Premature digging or tilling can readily regenerate underground plant parts. If you start to work the soil too soon, then you will have big problems if you planted the area with ornamentals and even bigger ones if you planted with a groundcover. Besides giving the sprayed area plenty of time to die, learn your weeds, knowing what they are (and how to control them) is just as important as knowing the ornamentals growing in them.

Remember, glyphosphate based products kill whatever they are sprayed on, so care must be taken to only spray the weeds and not your plants, annuals or perennials. Trees with thick bark are generally not harmed, but young trees with soft, unhardened bark such as young Dogwood, Locust, Linden, etc... can absorb this chemical through their bark and you may kill or damage the tree. Spray around your trees and shrubs but do not spray their bark directly. Top

I can't begin to tell you of all the people throughout the years that have bought this product, used it and then told me it doesn't work. Of course, upon cross examination, I came to find out, as I had already known, that it did kill the weeds… and more of the same weeds did come back. Let me say it again, THIS IS A POST-EMERGENT HERBICIDE. This product will kill any existing weeds or vegetation you spray it on, but it will not kill those little things that fall from the top of the plants, I believe they are called 'seeds.'

Weeds are just like any other plants, there are many different kinds and they have many different bloom seasons, and when you have flowers, you have seeds. Some weeds drop seeds that germinate right away, in the same season, others drop seeds that lay dormant until the following year. So you will find that many weed seeds that have been dormant during the winter season will germinate and burst into growth in the Spring like everything else, in your lawn, your garden, your beds and anywhere else they happen to be. Seeds…Now you need to think about a pre-emergent herbicide.

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Winter Weeds

In climates with a long dormant winter season, you may notice that there are some weeds that stay evergreen throughout the winter months, like chickweed, ground ivy and clover, which are considered broadleaf weeds and can be very invasive. Another cool season weed, Henbit, is similar to ground ivy and is distinguished by it's 4-sided stems, this can show up in late winter and take over quite rapidly. Late Winter / early spring spraying of these types of weeds can get you off to an early start with your weed control. If they are growing in beds where other plants are dormant, you can spray them without fear of damaging your dormant plants.

Some other troublesome cool season weeds are wild onion and wild garlic. Wild onion has no bulblets at it's roots and the leaves or stems are not hollow. Wild garlic has tiny bulblets at the root base and the leaves are hollow. Pulling either of these out only increases their production, they must be dug out or sprayed with repeated applications of glyphosphate until they are gone. Never allow them to flower or seed will be set and you will have a real problem.

As a perennial grower for many years and in a climate where the Winters can be long, one way I have found to get a head start on my weed control is spraying them in the middle to late Winter with a glyphosphate product. I generally do this on a warmer day, when the temperature is above 40 degrees, but only when the perennials are still dormant under the soil with no sign of visible growth. These cool season weeds are generally noticeable in late Fall, but I much prefer to allow them to grow throughout my field beds for the Winter. The reason is, they help prevent heaving of any plants that may not be that well rooted in, (the weeds act as a layer of mulch on the ground surface.) I wait for a warm spell in late winter, early spring and then spray them. This is much easier than trying to spray around the growing plants later. After all, I know I am not in a big hurry for them to die, so once I spray them, I know that they will die off before my plants start to grow.

Pre-emergent herbicides can be applied almost any time of the year. In simple terms these pre- emergent herbicides, work by forming an invisible chemical barrier on the soil surface that prevents the weed seeds from germinating. The best advice for applying pre emergent herbicides is to do it last. Do it after you have planted your plants, applied mulch or after any hand weeding. If the area is disturbed after applying pre emergent herbicides and the barrier is broken, weed seeds will grow.