How to stop seeding on weeds after flowering

How to Kill Weed Seeds in Soil [5 Easy Methods]

To kill weed seeds in soil you will have to apply one or more of the following methods:

  • Heat soil to temperatures high enough to kill weeds seeds
  • Force seeds to sprout and destroy growing weeds
  • Apply chemical or natural weed killers that prevent weeds from sprouting
  • Use flame weeding to destroy weeds and seeds at once
  • Layer mulch in garden areas to suppress weed sprouting and attract insects that eat seeds

With this arsenal of tricks for killing weed seeds before they sprout, you can stop the spread of weeds in both your lawn and garden.

Table of Contents

5 Tips for Killing Weed Seeds

Rather than spending time and effort battling weeds as they sprout, attack weeds at the source by killing weed seeds. Each of these methods destroys weed seeds, which ensures you won’t have to battle recurring weed invasions. Try these ways to get rid of weed seeds yourself.

Solarization

Soil solarization is a very powerful method for killing weed seeds. Weed seeds begin to die if soil temperatures surpass 108 degrees, with full seed death ensured by soil surface temperatures of 140 degrees or more. Solarization uses clear plastic tarps to trap heat at the soil surface, killing weed seeds within the tarped area. To solarize an area, follow these steps:

  • Clear the area of all vegetation through use of a hoe or other garden implement. Remove any woody stumps
  • Till the soil to further break up any weed root systems left behind.
  • Rake away all vegetation residue
  • Water the tilled and cleared soil with a garden hose until it is damp.
  • Lay a sheet of clear plastic over the area. Weigh it down tightly at the edges
  • Leave the plastic in place for at least two months.

Solarization is the best method to reclaim a weedy garden or other area. It is a “clean slate” for your soil, because seeds will be destroyed by the solar heat trapped beneath the plastic.

It is typically tough to implement solarization in large areas and is not usually suitable for use in lawns, where you may want to preserve grass or other plants. Pre-emergent weed killers and flame weeding are much better for use in lawns.

Till and Kill

Weed seeds can lie dormant in soil for decades and are only “activated” when brought to within an inch of the surface. One method to rid soil of dormant weed seeds is to force these dormant seeds to sprout, then attack them with a powerful natural or chemical weed killer. To do this:

  • In spring, till the affected area. Tilling brings dormant seeds to the surface
  • Water the area for 1–2 weeks with a sprinkler or soaker hose
  • When weeds begin to sprout, apply the weed killer of your choice

This is another “clean slate” method, where you force weed seeds to show themselves and then kill young weeds before they mature and cast seeds. Because of the invasive tilling step, it is not best used in areas with desirable grasses and plants.

Use Pre-Emergent Weed Killer

Pre-emergent weed killer stops weeds in their tracks. It works by attacking weed seeds just as they begin to germinate, killing them before they even poke above the surface. It’s a weed killer so good, the only sign it’s working is that there will be no new weeds at all.

How to stop seeding on weeds after flowering

Preen Garden Weed Preventer: Blocks weeds for 3 months. Guaranteed

Why You Should Never Let a Weed Go to Seed

Prevent weeds from growing in your garden and give them a boost of plant food with Preen Garden Weed Preventer Plus Plant Food.

A big reason that weeds are such effective invaders is that most of them are very prolific seeders. It’s not unusual for a single weed plant to throw off hundreds of viable seeds. If weeds are left to grow and produce new seeds, any that fall to the ground can live for years in the soil. Some can live for decades. That’s why the number one rule in winning the long-term battle against weeds is to stop them from growing at all.

Dealing with weeds you already have

If common spring-time sprouters like chickweed, purple deadnettle, dandelions, garlic mustard, and creeping speedwell have already flowered, a steady supply of summer weeds will be attempting to flower and set seed. Some of the worst summer seeding weeds include pigweed, purslane, thistle, lamb’s quarter, black medic, spurge, bindweed, Japanese knotweed, and assorted grassy weeds.

Pulling and/or digging is the most immediate, effective control. Just be sure to get roots and all or else many weeds will simply sprout new leaves from the roots left behind.

Be persistent, and you’ll eventually win – or at least gradually reduce the outbreaks by denying weeds from reproducing via seeds. Even if you can’t pull or kill all existing weeds, at least patrol enough to cut, hoe, or weed-whack any that are forming flowers or flower stalks.

Preventing future trouble

Bare soil only invites weeds, so it is best to add plants to bare spaces and add a few inches of mulch to your landscape beds to fill the space, leaving no room left for weeds.

Granular weed preventers such as Preen can go on top of mulched, planted beds to further stop new weeds before they have a chance to sprout and grow. Two to three applications per year can give season-long protection, depending on your climate and which type of Preen you use.

Preen offers many different options for controlling weeds in your landscape.

    provides protection from new weeds for up to 6 months and is labeled for use around 600 plants in perennial flower beds; around groundcovers, trees, and shrubs; and in xeriscape settings and rock gardens. blocks new weeds from germinating in your garden for up to 3 months and is labeled for use around 200 established flowers, vegetables, trees, and shrubs. blocks weed seeds from germinating in your garden for up to 3 months, and gives your plants a boost of plant food for beautiful, radiant blooms. is a natural way to keep weeds from sprouting in your vegetable garden. Providing 4-6 weeks of weed protection, Preen Natural can be used around any plant, including established vegetables, herbs, and fruits.

Remember, every weed flower you prevent or eliminate now could translate into hundreds of fewer weeds you’ll have to deal with later.