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Turf Tips: Controlling Winter Weeds

This post was originally published in March 2017 and was updated with new product recommendations on April 2, 2021.

David Yost, Merrifield Plant Specialist and Turf Expert

Spring is just around the corner. Before long you’ll be sowing grass seed, applying fertilizer, and mowing the lawn! To return your lawn to a thick, healthy state, March is the time to begin controlling pesky winter weeds currently taking over your lawn, and preventing summer weeds.

Winter weeds include chickweed, bittercress, henbit and deadnettle, as well as perennial weeds, such as clover, dandelion and wild violets. These winter weeds actually germinate in late September and early October, but they often go unnoticed in the fall when they’re just young seedlings. They overwinter as a small rosette, and come spring they are ready to strike with a vengeance!

Winter weeds typically flower in March, but can start blooming in February if temperatures are warm! Regardless of when they bloom, you can stop them dead in their tracks with the right control product.

Products to Control Winter Weeds

Two of our recommended products for Trimec Speed (a new product from Gordon’s for residential use, comparable to Speed Zone, their commercial product), and Bonide Weed Beater Ultra. Generally speaking, liquid weed killers are ideal for controlling actively growing weeds because they typically provide better surface area coverage than granular products. Plus, since they are applied as a spray, they can be turned on or off as needed, limiting waste or overuse.

We really like Speed Zone as it contains the same three active ingredients as the other products, but also has Carfentrazone, which makes it work faster and be effective at lower temperatures. Speed Zone also has a two-week waiting period before reseeding the lawn, compared to the three-week waiting period that most of the other products require. This allows you to get started on your overseeding project sooner so that you will be growing thick and healthy turf.

Most winter annuals can be controlled with just one application of weed killer. However, because perennial weeds live year-to-year with an established root system, some of them may be more difficult to control than others. Clover, for example, can typically be controlled with just one application, while others, such as wild violet, may take several applications to effectively control.

Regardless of the weed control product you use, none of them will hurt your lawn if they’re used as directed. Be sure to treat any existing broadleaf weeds in the lawn now, so that you’ll be ready to start building a beautiful new lawn from a clean slate.

Turf Tips: Liming the Lawn

David Yost, Merrifield Plant Specialist

To grow healthy grass and keep weeds at bay, the pH level of your soil needs to be between 6.2 and 6.8. Soil pH influences the availability of plant nutrients. A low pH level makes phosphorus remain bound to the soil and not be absorbed by your lawn. Without adequate phosphorus, your lawn will not grow vigorously and healthily.

In our Washington, D.C. metro area, our native pH level is generally between 5.0 and 5.5 (on a scale from 0 to 14). A pH level lower than 7 is acidic, and higher than 7 is basic or alkaline. Our native soil pH is great for acid-loving plants like azaleas, rhododendrons and camellias. But to grow thick, healthy lawns in our area, we generally need to raise the pH level of our soil. This is where liming comes in.

Each time you apply lime at the recommended rate, it will raise the pH level of your soil approximately ½ point over the course of a few months. If you need to raise it further than that, you can reapply lime as needed.  Just make sure there is at least a six-week interval between applications. Once you get your desired soil pH level, you typically need to apply lime once every two years to maintain the level.

Spring is an ideal time to apply lime, but it can be done any time of year when the ground isn’t frozen. After you apply lime, you need to water the lawn thoroughly. This will help wash all of the product off the grass and down into the soil where it belongs.

Testing your soil

There are a few ways to determine the pH level of your soil. You can use a pH meter, a pH test kit, or you can send a soil sample to Virginia Tech and they will send back a detailed analysis of your soil, including the pH level. You can pick up all of these supplies at Merrifield Garden Center.

Types of lime

There are several different forms of lime. Some come in granular form, while others come either pulverized or pelletized and packaged in 50 lb. bags, which cover 1,000 square feet. The pulverized or pelletized packages are ideal for large properties with extensive lawn areas.

Fast Acting Lime is an easy to use, pelletized lime that can be applied at lower rates. Mag-I-Cal is lime combined with humates, an organic supplement that improves soil structure, nutrients and moisture holding capacity. If you aren’t sure which lime is best for your situation, please ask one of our lawn specialists for assistance.

Turf Tips: Seeding & Fertilizing

David Yost, Merrifield Plant Specialist

A thick, healthy, dark green lawn is important to the look of your overall landscape. Colorful annuals, healthy shrubs and stately shade trees are wonderful features, but the overall appearance of your property is often dictated by the lawn. Having a beautiful lawn is not as difficult or time consuming as you might think. Mowing the lawn is the biggest chore, but all the other tasks are rather minimal.

Spring is the ideal time to get started building a healthy lawn. Controlling weeds is the first order of business. Next up is seeding and fertilizing, two simple steps that can be done the same day, and in any order.

Seeding

Seeding gives you the opportunity to introduce new and improved varieties of grass to your lawn. The term “overseeding” simply means applying grass seed “on top of” the existing lawn. New seeds will settle down on the soil surface between existing blades of grass, and from there it will germinate and fill in the lawn.

Although we carry many different types of grass seeds, we recommend our private label options as they are custom blended for the specific conditions in our Northern Virginia area. The varieties in our mixtures were selected because of their superior performance in local and regional turf trials conducted independently by Virginia Tech and the University of Maryland. We have three different blends of grass seed:

Merrifield Tuff Play

  • Our most versatile and popular mixture. Great for high traffic areas as it contains top performing tall fescues with a touch of Kentucky bluegrass.
  • This mix performs well in full sun to 70% shade conditions.
  • It establishes itself quickly, tolerates drought and wear and tear, and is resistant to disease problems.

Merrifield Sunny

  • This blend contains top performing varieties of Kentucky bluegrass and perennial ryegrass for a premium lawn with a rich, dark green color.
  • This mix performs best in full sun to part shade conditions and requires more maintenance and water than the fescue blends.
  • Good traffic tolerance.

Merrifield Shady

  • This mix contains top performing fine-textured fescue, shade tolerant perennial ryegrasses and Kentucky bluegrass.
  • This mix is ideal for use in moderate to heavy shade conditions.
  • It produces a soft, fine-bladed grass that is not quite as traffic tolerant as Merrifield Tuff Play.

If you need assistance selecting the right seed for your lawn, stop by or call the garden center and speak with one of our turf experts.

Before you seed, mow the lawn and rake out any thatch or dead grass. Then you can apply your grass seed with a drop or rotary lawn spreader to ensure proper coverage. If you have any bare spots, you’ll need twice the amount of seed in those areas. Then cover those areas with soil or straw when you are done.

Fertilizing

Fertilizer is very important to the overall health of the lawn. It provides beneficial nutrients necessary for it to perform at its best. At a minimum, fertilizer contains the nitrogen, phosphorous and potassium your lawn needs. Many also contain iron and other micro-nutrients that will help your lawn thrive.

At the time of seeding, we recommend fertilizing with Merrifield Select Lawn Food 14-18-14. This high phosphorous formula will aid in seedling germination and promote strong root growth, which is critical to new seed. In the fall, we recommend following with two applications of Merrifield Premium 26-0-12. After you have seeded and fertilized, be sure to water the lawn thoroughly.

Turf Tips: Preventing Summer Weeds

David Yost, Merrifield Plant Specialist and Turf Expert

Untreated summer weeds have a way of wreaking havoc on our lawns. The good news is that they haven’t germinated yet. You can intervene in the process by applying a summer annual weed preventer now. If you haven’t already, you’ll want to start by treating any winter weeds that currently reside in your lawn.

Types of Summer Weeds

Summer weeds include varieties of grassy and broadleaf weeds. Grassy weeds include crabgrass—the most infamous of all—goosegrass, foxtail and Japanese Stiltgrass. Japanese stiltgrass is now the most common weed in the state of Virginia. Each of these plants produces over 1,000 seeds that will remain viable in the soil for 3 to 5 years.

Many broadleaf weeds begin germinating in early spring and include spotted spurge and lespedeza, among others. Regardless of what type you have, all of these will stick out like a sore thumb in an otherwise healthy and attractive lawn.

Preventing Summer Weeds

To determine which product you should use to prevent summer weeds from attacking your lawn, you must first decide if you are going to seed the lawn this spring.

If you’re not planning to seed the lawn

If you are not seeding the lawn this spring, there are three different products you can use to control summer weeds:

  • Preen Crabgrass Control
  • Organic Corn Gluten

Preen Crabgrass Control contains dimension, a very effective ingredient that prevents summer weeds. Both products will remain active in the soil for 2 to 3 months, which means you need to put down two applications per year (for example, one in mid-March and another in early June).

Corn gluten is an organic weed preventer, which naturally inhibits all seed growth. This product will last about 1 to 2 months in the soil, which means you need to put down two applications per year (for example, one in mid-March and another in late April or early May).

If you put down two applications of any of these products in the spring and early summer, your lawn will be ready for fall seeding. Fall is an ideal time to seed as the warm days and cool nights provide the optimal growing conditions for cool season grasses.

If you are planning to seed the lawn

If you are seeding the lawn this spring, we recommend using Scott’s Step 1 for Seeding (Starter Food with Weed Preventer). This product contains tenacity, an ingredient that can distinguish between the “bad” summer weed seeds and the “good” grass seeds. This product also provides starter fertilizer to help your grass seed germinate.

Once your new grass seed has germinated and been mowed twice (this typically occurs about 6 to 8 weeks after seeding), you can apply a second application of another summer annual weed preventer. For the second application, we recommend using one of the three products for not seeding your lawn. By this point, your new grass will be mature enough to withstand the dimension ingredient. You should only use the Scott’s Step 1 for Seeding for the primary application as your lawn doesn’t need a second application of the starter fertilizer that comes automatically in the product.