Occultation typically requires at least four weeks to be effective. The longer you keep the covering in place, the more effective it will be, up to about six weeks, at which point efficacy begins to level off. Common materials for occultation on a small scale include common tarps and cardboard.
A tarp can smother weeds before planting and also deter future ones in a bed. Its dark color absorbs heat and warms the soil, Fortier explains. “Weeds germinate in the warm, moist conditions created by the tarp but are then killed by the absence of light.”
Leave the plastic on the ground for 2-3 Months
Grass and annual weeds are the first to go but hardier weeds can take longer. In warmer months it can take as little as two months for the plants underneath to die and rot down. In winter leave the plastic for at least six months.
Before you can remove the plastic, you'll want to wait six to eight weeks for the soil solarization process to take place. After six to eight weeks have passed, you should have healthy soil that's ready for planting again.
Using Bleach to Kill Weeds Permanently
Apply one cup of bleach, undiluted, to the afflicted area. Wait until the weeds turn brown before pulling them out of the ground.
For learning how to kill weeds permanently, it's important to tackle them at the root, especially perennial weeds. 'One of the main ways to get rid of weeds permanently is to dig them up and remove all of the roots to stop any further growth,' says Henry.
Generally, this process will be most effective in areas that receive full sunlight during the day as any shade produced by trees or buildings will hinder the process. June, July, and August are the best months to solarize your soil since this is when temperatures are highest.
Clear plastic tarps from your local hardware store (2-6 mil) are sufficient for solarization. In dry climates, the process typically takes around two to three weeks during hot summer months. The process is complete when the vegetation underneath the tarp is dead.
Solarization is most effective when done during the hottest weeks of the year. The best time for solarization of soil in inland California is from June to August, although good results may be obtained starting as early as late May or as late as early September in the southern California desert regions.
Black plastic, on the other hand, is primarily used to eliminate weed growth. The material is thin, so it will only last for a few weeks. Yes, you can extend its life by adding a layer of mulch, but this will not stop the product from degrading because of the elements.
A popular method of sterilizing soil is called solarization. Solarization harnesses the power of the sun to heat up and sterilize the soil. Typically, this is done using black or clear plastic. This method of sterilization requires an extended amount of time, around 4-6 weeks, of full sun exposure to do its job.
Have you considered a tarp for your garden? A tarp can block the sun and keep weeds from growing. You have to be careful, though. Most tarps don't allow air to flow, so they can also keep your plants from thriving if you cover them with tarps.
They explained: “Targeting and killing the plant's root is what permanently kills weeds. You can use natural and manufactured weed killers; however, they will ultimately come back if the plant's root survives.
Add 4 - 6” of soil or compost or mulch on top of newspaper/cardboard layers 6. Allow 6 - 8 weeks for the grass under the paper/cardboard & compost layers to die back. Be patient! The longer you allow the decomposition process to take place, the better results you will see.
You can purchase a groundcover weed killer that will target weeds and not harm the groundcover in some cases. To prevent the problem, it is best to install weed barrier fabric prior to planting. If it's too late for that, manual pulling or the appropriate herbicide may be the only solution.
The short answer is no. There are too many variables involved to rely upon final grade and top soil as an effective weed treatment including any potential weed seed cache that comes in the top soil.
Smothering effectively kills weeds in areas earmarked for future planting. After mowing or cutting off the top growth, lay down a mulch of heavy cardboard, newspaper (in a layer at least three dozen sheets thick), or black plastic. Overlap these materials so weeds can't grow through the cracks.
Weed when the soil is wet and soft.
Pull weeds soon after watering your plants or a rain shower; when the soil is moist, the whole weed is more likely to come out by the roots. It's perfectly fine to put pulled weeds in your compost bin, where the naturally hot temperatures will destroy any seeds.
A great season for weeding, Spring ! Spring weeding is a crucial step. This treatment has preventive virtues, as you will be removing weeds while they are still small. Indeed, weeds tend to quickly become invasive at that time of the year.
Steam application to soil has a similar effect to soil as soil solarization, although the length of time for treatment is much less for steam.
For some, this may be as early as March, while others may have to wait until May or early June depending on the region and climate. Tilling wet soil damages the valuable, existing structure which you'll need as your garden grows.
Acetic acid is a terrific weed killer but it is also a terrific plant killer! Acetic acid works by drawing all of the moisture out of the weed or plant leaf. It is quick to work and it would be common to see a weed or plant brown up after only a few hours of having vinegar applied to its leaves in the full sun.
Rock salt is actually a super-effective and totally natural weed killer that is ace at clearing a gravel driveway. Simply sprinkle some rock salt on the ground surrounding any weeds you can see and then sit back and watch as the salt kills the weeds in just a matter of days. It's almost unbelievable.
Glyphosate, the ingredient in Roundup and other products, is translocated from the leaves to the roots of a weed. Vinegar is not translocated. It is true that 5% vinegar (acetic acid) will kill young, tender weeds but it does little damage to established weeds.