What’s In Weed and Feed?
Because “weed and feed” is an umbrella term, there’s no one set list of ingredients for it. Not only is it sold in different forms (granules vs liquid), but it can also serve different purposes. If you’re trying to thwart weeds before they emerge, then you need a weed and feed that contains a pre-emergent herbicide. But if you need to kill weeds after the fact, the product to use is one with a post-emergent herbicide. The “feed” ingredients are not always exactly the same either. For example, the NPK ratio may vary (some mixes leave out phosphorous altogether). But the typical bag of weed and feed with post-emergent herbicide contains:
2, 4-D, dicamba, MCPP (herbicides)Nitrogen, phosphorous, and potassium (fertilizer)
A typical bag of weed and feed with pre-emergent herbicide may contain, among other ingredients:
Dithiopyr (herbicide; often sold as “Dimension”)Nitrogen, phosphorous, and potassium (fertilizer)
Does Weed and Feed Work?
Weed and feed can work, but only if you take the trouble to become informed about lawn care. These are not products suited to those unwilling to do any homework. Timing is of the essence. Weed and feed is typically applied in spring, but timing here is complicated by the fact that you need to time two different things: weeding and feeding. Let’s assume you’re applying weed and feed with post-emergent herbicide: If you apply it too early, you may kill only a small percentage of the weeds. The weeds that haven’t yet emerged will avoid the post-emergent. But, if you apply it too late, your grass won’t receive the feed it needs to get off to a good start in spring. Consequently, you’ll need to strike a balance. Your best bet is to apply weed and feed approximately when you notice the grass needs its first mowing of the season. In their criticisms of weed and feed, detractors go well beyond pointing out the difficulty of striking this balance. They argue that, even if you arrive at just the right balance, an application made so early in the year (to satisfy the needs of your grass) generally doesn’t coincide with the ideal timing for killing weeds, most of which emerge later. Consequently, a potentially harmful chemical is being applied to your lawn that does relatively little good. While this is true, the argument is unlikely to persuade a homeowner whose lawn has been overrun by dandelions and who desperately wants to get rid of them: Dandelions are an example of a weed that emerges early in the year, so a post-emergent is effective against them. Moreover, the argument limits itself to the issue of the effectiveness of post-emergent herbicides and fails to consider the utility of pre-emergent herbicides. Crabgrass is one of the most pernicious weeds and is best controlled with pre-emergent herbicides. Weed and feed designed to suppress crabgrass seed germination in spring could be the right answer for you if you’ve been fighting a losing battle with crabgrass.
How Weed and Feed Can Harm Your Lawn
But such a product will never be the right answer if you’re an organic gardener. Environmentalists are generally opposed to the use of chemicals on the lawn due to the potential harm they cause the environment. To illustrate how controversial weed and feed is, we need only turn to Canada. That country banned it in 2010 (although you could still buy the herbicide or the fertilizer separately). The ban was meant to target cosmetic use of weed and feed (on residential, commercial, and recreational turf, such as golf courses), carving out an exception for agricultural use. Continuous use of weed and feed may even negatively impact long-term lawn health. Weed and feed harms soil micro-organisms that are beneficial to grass.
Alternatives to Use
First of all, always ask yourself the question, Do I really need to apply an herbicide? When you notice the grass needs its first mowing of the spring, look around and see how many weeds are present. If you have done a good job in the past of keeping your lawn weed-free, you may not need to use a post-emergent herbicide. As for pre-emergent herbicides, an organic choice is corn gluten meal, which also contains some nitrogen (natural fertilizer), making it something of an “organic weed and feed.” More generally, simply realize that it may be better to apply herbicides and fertilizers separately, rather than together. It may take more time, but they may work better when used separately, since you’ll be applying them when they’re most effective. This way, you can also limit the adverse impact of potentially harmful chemicals by spot-treating weeds with post-emergent herbicide when and where they appear, thereby reducing the total amount of herbicide released. It’s easier to go totally organic on a small lawn than on a larger lawn. When the surface to be maintained is minimal, it becomes more feasible to weed your lawn through hand-pulling and to feed it with compost.
