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.
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.
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.
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.
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.
Additionally, some have moss control added for any moss present. It’s important to feed with a specific autumn lawn food such as Miracle-Gro EverGreen Autumn Lawn Care, to get the grass ready for the colder, wetter weather in winter and get the lawn ready for spring. Autumn lawn feeds will be low in nitrogen, as we don’t want to encourage any top growth, which can be soft and easily burnt by frost.
This photograph on the right shows the difference feeding your lawn can make. On the left section the lawn has been fed with a granular lawn food, on the right section nothing extra has been applied. As you can see, the fed section of lawn is much greener and healthier looking.
Your lawn needs another type of feed come the autumn, which will keep the grass growing at a slow rate and not so lush, but still green. Also it prepares your lawn for the winter, by building up the roots and health of the grass to withstand the cold.
Spring and summer lawn feeding
The best lawn feed (or fertiliser) to use is one that provides both protection from weeds while systematically feeding your lawn. Ideally, lawn feed should be applied between April and September with Miracle-Gro EverGreen Complete 4 in 1 providing year-round feed when applied no more than twice a year.
Feeding in autumn helps encourage strong root growth, so your lawn will recover quickly from a harsh winter and put on lush green growth in spring. Autumn feeding is actually the most important feed and integral part of lawn care!
Whichever product you are using, always carefully read the label before use and apply according to the instructions.
Once the weeds and moss are under control later in the spring, move over to just a lawn feed to keep the grass looking thick and green. Liquid lawn feeds via a hose end feeder are ideal for using in late spring into summer as they water the lawn as well in dry periods.