Lawn Weed Control Tips – Fertilizing To Prevent Weeds In Lawns

Fertilizing As An Important Step To A Weed Free Lawn

Photo of a weed free residential lawn

Weed Free Fertilized Lawn

I’ll say it again. The best weed control in lawns (besides concrete) is a thick healthy stand of turf grass that leaves no room for invasive unwanted plants to gain a foothold. And while this is often easier said than done, it’s not unobtainable. Even so, it can still take several seasons and a lot of work to reach that point. However, once this goal is reached, it’s a lot less work to keep a yard healthy and weed free.

Proper fertilizing, along with other steps like proper watering and pre emergent, plays a very important role in creating healthy weed free lawns. Besides the obvious reason that it helps create healthy grass plants than can more successfully choke out weeds, there are many opportunistic weeds such as sand bur that prefer an infertile soil in order to thrive.

While the mechanics of actually spreading fertilizer on the lawn are simple, proper methods are often overlooked, misunderstood, or not known at all. Improper applications can actually make the turf grass weaker or have little benefit at all.

When And How Much?

For most folks, a fertilizing program consists of a heavy application of high nitrogen fertilizer in the Spring and generally nothing else for the rest of the growing season. This usually produces a very green fast growing lawn for about six weeks along with the need to mow every three days or so. The desired results are there…at first. However, long term results can be minimal along with some not so obvious problems later in the Summer and in the grass plants themselves.

While a heavy nitrogen application can produce a fast thick beautifully green colored lawn to start, it can actually create very weak plants with very little root system that can’t withstand disease and drought. This in turn will eventually leave a very thin stand of turf with lots of room for invasive weeds.

Also, nitrogen is very soluble and readily available in most commercial fertilizers and plants will absorb as much as they can and more than necessary while it is available. Then it’s gone. It’s best to apply several light fertilizer applications over the growing season rather than one or two heavy applications all at once. This helps ensure that there is always an adequate supply throughout the season rather than a shot in the arm and then nothing.

It’s best to apply several light fertilizer applications over the growing season rather than one or two heavy applications all at once.

While some manufacturers instructions on the bag recognize and follow this approach, most don’t. And while the manufacturers generally give proper application amounts per application, the nitrogen is generally depleted before the next suggested application. Remember what I said about nitrogen being very soluble and that plants will use more than they need until it’s gone?

Macro & Micro Fertilizer Nutrients

Most lawn fertilizers will have phosphorous and potassium along with the nitrogen which are generally the most vital, utilized, and necessary elements required for good healthy plants and root systems. These are called Macro Nutrients. However, these aren’t the only nutrients required for healthy plant growth. Plants also need a periodic micro nutrient supplement.

While most soils will have adequate amounts of the lesser micro nutrients available, it’s still good practice to supplement the soil with one application of a full spectrum macro and micro nutrient fertilizer once every three years or so. Some lawn fertilizers do have minor amounts of iron, zinc, copper, etc. in them or it may be necessary to incorporate a general purpose or tree food mix into the program. Once every three years is generally more than enough for most soils.

Some lawn fertilizers do have minor amounts of iron, zinc, copper, etc. in them or it may be necessary to incorporate a general purpose or tree food mix into the program.

A Word About Soil PH

Proper soil PH is critical for proper nutrient uptake in lawn grass and other plants. For example, there could be plenty of iron in the soil but if the soil ph is incorrect, it will be locked up in the soil and the lawn can’t access or use it. And with common fertilizers, it doesn’t matter how much you apply, it won’t be accessible.

Proper soil PH for most grass types is 6 to 7 which is slightly acidic to neutral. Generally, the soil around here in Carlsbad, Artesia, and Southeast New Mexico is a bit on the alkaline side. For alkaline soils some agricultural sulfur may be necessary to bring it in balance. For acidic soils, a bit of lime may be necessary.

If a fertilizer application doesn’t bring a dull lawn to proper healthy color, it’s best to do a PH test before you go dump another application on it. You could have plenty of nutrients in the soil but the plants simply can’t access it and use it.

Inexpensive soil ph and nutrient test kits are usually available at hardware stores, do it yourself centers, or online.

A Word About Winterizing Fertilization

Winterizing with fertilizer is an important step for cool season grasses like Fescue that stay green in the colder months. Obviously, if they’re green, there’s something still going on there. However, the nutrient requirements are different at this time of year and a fertilizer with very little nitrogen and medium amounts of phosphorus and potassium is best for root production and preparation for Spring.

Warm season grasses like Bermuda and St. Augustine that go dormant in the colder weather do not need winterizing in the Fall. While the grass plants are still somewhat active at the root level preparing for next season, they don’t need added nutrients.

Late Fall fertilizing of warm season grasses can actually cause great harm to the turf. A late Fall application of nitrogen and other nutrients can stimulate unwanted growth as the turf is trying to go dormant. And if the plants are green and growing when a freeze happens, it will kill the grass that is growing leaving bare spots in the Spring. And bare areas not only mean an ugly lawn but are also areas where weeds can set up home.

While it may not seem as direct a link to weed control as pulling weeds, herbicides, and pre emergent applications, fertilizing is a very important step in a long term lawn weed prevention program.

If you have any questions or would like us to help you develop a weed control program for your lawn or property, give Horizon a call today at 575-725-9331. Whether you hire us or do it yourself, we’re always happy to offer advice and help out.

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