How to Kill Weeds in Newly Seeded Lawn?

A healthy lawn is a source of great pride for many gardeners, but they don’t just happen by themselves – a thriving, finely-manicured lawn requires care, attention and quite a lot of work.

Sometimes bald patches may appear in your lawn, something that you can rectify by overseeding to grow new grass and fill in the gaps. This can be a delicate operation since new grass seedlings need to be nurtured, and a common problem is that these patches of new grass are prone to invasions of weeds.

To help with this well-known issue, here, we talk about killing weeds in newly seeded lawn.

Here’s a video that discusses the different types of weeds you may come across.

Prevention is far better than sure

When overseeding and nurturing new grass, prevention is far better than cure. If you can stop the weeds invading and becoming established in the first place, it will make your life a whole lot easier.

For this reason, let’s start by talking about what you should do to stop the weeds taking root in the first place – after that, we can move onto dealing with weeds once they begin to appear.

· Choose seed that is free of weed seeds

The first thing to do is to make sure the grass seed you are spreading is “clean” and free of any other kinds of seeds. This will at least mean you are not spreading weed seeds when you seed your lawn.

When you buy your grass seeds, check on the packaging to see the contents. It should be labeled “weed seeds 0%” and “other crop seeds 0%”.

Also, if you are cutting down weeds with a gas weed eater, and cordless weed eater or something similar, make sure you avoid spreading weed seeds over your lawn and contaminating the freshly sown patch of grass.

· Use the correct mulch

Some people use mulch when they spread new grass seeds, and this is fine – but make sure you choose the correct kind.

Traditionally, hay mulch has been used – but this is nearly always contaminated with weed seeds and should be avoided. Paper pellets are a better choice – they will help protect the new seeds, hold water well and also help prevent weeds from moving in.

· Keep grass healthy

Perhaps the best defense against invading weeds is a lush and healthy lawn. If your lawn is thick and thriving, weeds have nowhere to grow and are naturally kept at bay.

Obviously, when seedlings are just taking root, they can’t fight off weeds by themselves – but as they grow, if your nurture them properly, they will soon leave no space for weeds to grow.

This means following all the usual best practices is essential. Keep your new grass well-watered and well-fed. Don’t cut new grass too early and don’t cut it too short. If you give your new grass the best possible start, weeds won’t have the chance to become established.

What to do when weeds start to appear

What to do when weeds start to appear

Despite everything you do to prevent them from moving in, weeds are regular invaders of patches of vulnerable young grass. It is almost inevitable that you will have to deal with weeds at some point, and there are several strategies you can employ.

Here are some of the most important things you should be doing.

· Keep an eye on your new grass

With a new patch of seeded grass, you should be paying careful attention to how it is developing – and part of this is keeping an eye out for weed infestations.

If you catch weeds early enough, you can keep the situation under control – but if weeds become well-established, it can be more difficult to deal with them.

· Pull up weeds individually

If you see weeds beginning to shoot up in your patch of new grass, the first thing to do is simply to pull them up one by one. If you only have a small area of seeded grass to look after and you keep weeds under control from the beginning, this can be extremely effective.

With smaller weeds, grip them at the base and pull them up slowly and carefully. The aim is to remove the whole weed with its roots intact. Anything left in the soil can continue growing.

If weeds manage to grow bigger than just the first shoots before you catch them, use a small garden hand shovel to dig them up by the roots and pull them out that way.

Any weeds you dig or pull up should be bagged up and disposed of carefully so they don’t have chance to spread. Also, make sure you fill in any holes the weeds leave – otherwise you will be leaving inviting homes for new weeds to occupy.

If you are using your own composter, make sure you avoid throwing weeds onto your pile.

· Don’t apply weed killer too early

If weeds manage to become established, make sure you don’t apply weed killer too early. If there are more weeds than you can manage to pull out by hand, simply leave them. The rule is, don’t apply weed killer before your lawn is mature enough to have been mown twice.

If you apply weed killer before you mow your new grass twice, it will be too weak and may die along with the weeds you want to kill.

· After two mows, apply post-emergent weed killer

Once your new grass is more established and has been mown at least twice, you can consider applying weed killer. If you are trying to kill dandelions or other broadleaf weeds, this is the correct action to take at this stage.

The most important advice here is always to read the label carefully. There is always a specified waiting time between germination and the application of weed killer – and if you go too early, you may end up damaging your grass and even inviting new weeds to move in.

· Dealing with crabgrass and similar weeds

For weeds like crabgrass, the procedure is different. Since these are weeds that grow annually and die out in the winter, the best way to treat them is to simply wait for them to die. Then, the following spring, treat your lawn with pre-emergent weed killer to stop them returning.

Prevent infestations before they begin by keeping grass healthy

The best way to deal with weeds is to prevent them from moving in in the first place. Help keep your grass healthy and pull out weeds as they emerge, and your lawn will fight off new weeds by itself. If you have to deal with an infestation, don’t apply weed killer too early – and above all, read the label on your product carefully

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