Why did so many weeds grow where I planted my grass seed?

What Is a “Weed”?

Our world is green with all types of plants. All plants are useful and beneficial in some way. But…some plants are undesirable in areas created by man to serve his particular needs. These “plants out of place” are called weeds.

Weeds in a newly planted lawn are almost always a problem, but rarely is the source of these weeds the grass seed. The vast majority of grass seed sold by Pennington, as well as other grass seed suppliers, contains less than 1% weed seed. In fact, Pennington’s Premium grass seed products are 99.99% weed free! The amount of weed seed in every bag is regulated by law and clearly marked on the seed tag on the back of the bag. So where do all the weeds come from? Generally from one of the following 3 sources:

1. They were there all the time.

The most likely source for new weeds in your lawn is from weed seed currently in your soil. Even if you sprayed the area with a herbicide and killed all the actively growing weeds, millions of additional weed seeds are lying dormant in the soil just waiting for their chance to grow. In fact, a seed can lie in the soil for up to 30 years before germinating. So why do they germinate now? It’s simple. If you prepared your soil properly before planting, you may have loosened it up possibly by tilling or thatching. This action creates an excellent bed for the new grass seed to flourish, but it also acts as a catalyst for encouraging the germination of weed seeds.

2. Seeds are blowing in the wind.

The second most common source of weed seed to contaminate a new lawn is from other weeds in the area. Weeds are constantly producing seeds, which are disbursed across the area by winds. A newly prepared bed of damp, bare ground acts as a magnet to these weed seeds. Not much can be done to stop weed invasion from seeds blowing in the wind. The best practice is to keep nearby yards and fields mowed so they are not able to produce weed seeds.

3. Added Topsoil and Straw Contain Weed Seeds.

Two of the more common sources of weeds in a new lawn come from topsoil and straw. Topsoil, as well as other soil, almost always contains some weed seed. Even the most sterilized soil will contribute to your weed problem. However, always ask for weed-free soil to limit potential problems. Straw is often used a as mulch on the seed bed to protect the seed and hold in moisture. The concept is excellent, but many types of straw contain high amounts of weed seed, which was prevalent in the field from which the straw was baled.

SO I’VE GOT WEEDS. NOW WHAT DO I DO?

First, the problem may not be as bad as you think. Many weed seeds germinate at lower soil temperatures than grass seed and once the weed sprouts, it grows much faster. Consequently, in the early stages a lawn can appear to be much more heavily affected by weeds that it actually is. Your best bet for weed control is to pull or dig up the weeds. Be careful to limit any damage to the seedbed. You should avoid the use of any herbicides until after the new grass has been mowed at least 4 times, and the daily high temperature should not exceed 85? F.

Following these guidelines, a herbicide should generally be used in the following spring or fall after the seed was originally planted. This will allow the grass to strengthen its ability to withstand the herbicide. Remember, it’s important to choose your herbicide carefully and to only use selective lawn weed killers. Please note that non-selective herbicides will kill actively growing plants. Always read and follow product instructions prior to usage.br/>