Weed and feed fertilizers are often used in combination with seeding. Weed and feed formulations consist of two components: a herbicide to kill weeds and a fertilizer to strengthen the turf. The herbicide will weaken the grass as well as the weeds and the fertilizer will strengthen the weeds as well as the grass. When applying seed over a weed and feed application, remember that some weed and feeds can prevent grass seeds from growing.
It is important to know what kind of grass you have growing or want to have growing. Certain chemicals act differently on different species of grass and weeds. For example, the common herbicide 2,4-D is toxic to some cultivars of St. Augustine grass (Stenotaphrum secundatum), which grows in the area roughly covered by U.S. Department of Agriculture plant hardiness zones 8 through 10. Another common herbicide, atrazine, is potentially lethal to grass when applied in temperatures above 85 degrees Fahrenheit. Use the instructions on the bag of each weed and feed product to determine how it will affect seeding.
Types of Herbicide
Herbicides can target weeds before they germinate from seed – pre-emergent – or as developed plants – post-emergent. Before you seed, you can use a non-selective, post-emergent herbicide to control any weeds in the area to be seeded. Most of these can be applied up to two weeks before seeding to control any existing weeds. Herbicides should not be used after seeding until the new seedlings are established. Mowing and spot treatments can be used to control weeds until the seeded area is actively growing and requires only maintenance watering. Establishment times vary depending on the type of seed you use and your weather conditions.
Only use a weed and feed if the weed infestation is completely uniform over the entire lawn and all species of weeds targeted will be affected by the herbicide in the weed and feed. This scenario doesn’t occur often, so it is more likely the use of an herbicide and a fertilizer separately will be needed. If the weeds are uniformly spread over the area to be treated, match the appropriate weed and feed product to your grass, the seed you have recently applied or want to apply, and the time of year.
It’s important to know a little about herbicides so you can make the best choice for when to apply seed in an area that has been treated for weeds. The most common types of herbicide in weed and feed products are selective and systemic. Selective herbicides target a species of plant to kill while systemic herbicides work by being absorbed though the roots and then transported throughout the plant, killing it from within. Read the bag label to see what kind of herbicide is used in the weed and feed you are considering using or have used. The bag label will tell you how many days you must wait before applying seed to a lawn that has been treated with that product.
Always read and follow herbicide and fertilizer labels, especially the instructions for use on newly seeded lawns and your grass type. As a general rule, avoid pre-emergent weed treatments at least 10 to 12 weeks before seeding — or longer for some products. After planting, reserve broad-spectrum weed treatments until new lawns have been mowed at least two to three times; for fall-planted seed, that usually means spring.
Seeding success depends on an environment conducive to good grass growth. Knowing how your soil measures up on certain essentials, such as soil pH and plant nutrients, allows you to provide the foundation an outstanding lawn needs. Soil testing processed through a reputable soil laboratory eliminates guesswork and reveals changes you need to make.
Choosing appropriate grass varieties is the first step in ensuring your lawn performs up to your aspirations. Grasses vary widely in their preferences and tolerances, just like other types of plants. Kentucky bluegrass and Bermudagrass, for example, differ significantly in climate and maintenance requirements. Planting grass varieties appropriate to your growing region gives your seed a natural advantage.
6. Planting without regard for proper timing
For most of the country, fall is the best time to plant grass seed. This is when cool-season grasses such as Kentucky bluegrass and tall fescues peak in growth, and conditions enhance fast germination and establishment. When paired with innovations such as water-conserving Pennington Smart Seed, proper timing leads to other advantages, including less input of resources, less maintenance and better results.
Even with similar seed types, all grass seed isn’t equal. Learn what’s actually inside the seed bags you or your lawn professional buy. By understanding the seed tags on grass seed products, you can be sure you invest in quality seed. Cheaper price tags can mean less seed versus fillers, old seeds past their prime, more weed seeds and lower germination rates. Getting seed right from the start benefits your lawn and budget.
Using the proper amount of seed for your project influences success, whether you’re starting from scratch or overseeding an existing lawn. New lawns or spot repairs take about twice the amount of seed needed for overseeding thin areas. Quality grass seed labels include guidance on optimal seeding rates to maximize your results.
Many homeowners think lime is a lawn care necessity, but that doesn’t hold true across the board. Normal lawn care can naturally cause soil pH to drop lower over time, and lime applications benefit lawns that need pH raised. But in some cases, soil pH may already be high. Using too much lime or applying it unnecessarily can be as damaging as failing to add lime when it’s needed.
You want a beautiful lawn for your family to enjoy, but it’s no longer enough to just mow it. You have to fertilize, water, kill weeds and then reseed any bare spots. Using a weed and feed product saved you some time, so now you’re ready to plant some grass seed. You may have to wait a bit longer, though, depending on the type of weed and feed product you used.
Since weed and feed products are designed to prevent germination — or to eradicate a living plant — they can, for the most part, have a similar effect on young turf grass. The only exception is the pre-emergent herbicide siduron, which is actually used to assist in seed germination. When using a pre-emergent that does not contain siduron, wait a minimum of two months before seeding. If using a product designed for broadleaf weeds, read the label carefully, because the active ingredient in these post-emergent herbicides have a wider range for the waiting period. Grass can be planted in as little as one month after application for products using 2,4-D to as much as six months for atrazine-based products.
Weed and Feed
Weed and feed products consist of fertilizers such as nitrogen or potassium, and a pre-emergent or post-emergent herbicide. If the weed and feed is designed for spring application, it contains a pre-emergent. If it is designed for later in the growing season, it incorporates a post-emergent herbicide. Knowing which one you are using is important because the herbicides affect plants in significantly different ways.
Pre-emergent weed and feed is applied in early spring so the herbicide is in place before the undesirable weeds germinate. Pre-emergent herbicide works by inhibiting germination. It must be watered with at least one-half inch of water to move the chemical from the surface into the soil. Post-emergent herbicides, however, must be applied while the weeds are actively growing because for the chemical to work, the herbicide must be absorbed into the plant.
When you are ready to seed your lawn, use a garden rake to remove debris and to break up the surface to ensure the seed comes into contact with the soil. Broadcast the seeds in two directions to ensure complete coverage, and water the ground lightly and often for up to two weeks — keeping the soil moist. Once seedlings have established, gradually reduce the frequency of the watering, but lengthen the amount of time per watering. This will encourage a deep root system for your grass.