To render all weed seeds non-viable, ratchet the heat up a bit more to 180 degrees. To eradicate all heat-resistant viruses and seeds, you would need to heat the soil to 212 degrees for 30 minutes.
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.
There are many different sterilants you can use for chemical soil sterilization, including formaldehyde, phenols, cresylic acid, ethylene oxide and methyl bromide, though the two most common are sodium azide and propylene oxide.
EPA Registered
Barren is a powerful, ready to use non-selective herbicide designed to kill all vegetation wherever it is applied. Kills all annoying weeds around buildings, storage yards and other industrial sites. Barren is also a soil sterilant, providing the longest lasting residual action available.
To kill off most viruses, disease, fungi, and mold, you need to heat the soil to 145 degrees Fahrenheit for 30 minutes. If you want to eliminate soil-borne insects—which include good guys along with the bad guys—you need to crank up the heat to 160 degrees.
You can also pack your potting soil in a layer of foil and place this on top of the rake. Heat the water and bring it to a boil. Keep it boiling for up to thirty minutes at least. Remove the heat source and allow the sterilized potting soil to cool before you touch it again.
Steaming leads to a better starting position, quicker growth and strengthened resistance against plant disease and pests. Today, the application of hot steam is considered the best and most effective way to disinfect sick soil, potting soil and compost.
Commercial Herbicides
These options, such as glyphosate (think: Roundup), are non-selective and kill grass and weeds permanently. They also kill down to the roots, which is not the case with most natural ways to kill grass. If you choose this method, wear long sleeves, gloves, and eye protection to limit exposure.
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.
Soil sterilant herbicides are “total kill” products that last in the soil for long periods, sometimes for 10 or more years, particularly in arid environments.
Even though vinegar is an acid, it breaks down quickly in the soil and, therefore, is not likely to accumulate enough to affect soil pH for more than a few days. Vinegar causes a rapid burn to plant tissue of susceptible species, so unintended injury is quite likely without knowing more information.
SpraKiL SK-26 Granular Weed Killer 6# (Soil sterilant)
Historically, the most common method for soil sterilization has been moist heat such as autoclaving. Additional sterilization methods include dry heat; ionizing radiation; or gaseous compounds such as ethylene oxide, propylene oxide, or methyl bromide.
Sprinkle full-strength baking soda on garden soil in paths and around plants where insects are an issue. The best way to apply the dust evenly and without over-application is by using a flour sifter. As a soil dust and repellant, baking soda is effective against ants, roaches, silverfish, slugs, and snails.
Our growing media products are not sterilized, and may contain microorganism including fungus. In fact, fungus/mold have been scientifically proven to improve the growth of plants by releasing nutrients from the organic material.
Bleach will sterilize soil if the goal is to remove dangerous fungus and bacteria. Unfortunately for plants, bleach will create an inhospitable and contaminated growing environment.
Soil pasteurization occurs at 160-182°F, but soil sterilization is at the water boiling temperature (212°F).
Why Does Soil Need To Be Sterilised? Some soil microbes can cause disease in plants. Small seedlings are especially vulnerable to disease, especially if they're being raised in the warm moist conditions of a greenhouse.