The best cannabis safe weed killers of 2021

Published Apr 5, 2021 12:00 p.m. ET
iStock / JohnAlexandr

Are you facing a cannabis grower's worst nightmare? Do your plants have bugs or weeds? Don't worry because there are some natural ways of getting rid of unwanted pests and weeds without harming your ladies or affecting the luscious green buds. Some of the best weed killer available is organic and will free your garden of many unwanted entities.

Every inch of your garden space designated for growing your cannabis plants has weed seeds. The best definition of a weed is perhaps to say that it is a plant planted by nature or any unwanted species that appear in your garden. Those seeds that are below an inch or two in the soil will not germinate as they need light, but each time you turn over the soil around your cannabis plant in your home garden, you are inviting a new crop of unwanted garden weeds to your cannabis plot.

If you are growing your legal four plants in Canada and want to ensure that everything your plants are being fed is organic and safe, then you can't forget about providing control for any unwanted plants. Safe weed killer for your ladies can be as easy as opening your kitchen cupboard. So, let's look at some of the best weed killer available that will help by protecting your cannabis plants.

Manual pulling out weeds

If you have a lot of time to spend in your garden, then hand pulling all of those weeds is for sure one of the best weed killer applications there are.

There are generally two classes of weed that may invade your cannabis plot:

1. Runners

These weeds do just that; they run in all directions at the same time. The weed puts out runners both above and under the ground. Cutting off one of the runners by pulling it out of the earth will not defeat the weed, as it will continue growing.

2. Taproot

These weeds have roots that resemble the core of a carrot. If you break off the root at ground level, it will continue to grow in your cannabis plot. Breaking off roots at ground level will not kill weeds if they’re this type.


Applying mulch around your plants will kill weeds. It takes time and can add to your expense, but it works. It is recommended to lay about an inch to two inches of mulch; this will smother anything trying to grow and deprive the weed seeds of light. It will also prevent those already rooted from thriving. A less expensive mulch can be used. Gather wood chips, grass clippings, or pine needles to be applied where you would put the more costly commercial mulch product. This process will need to be repeated every time you start new growth for it to be effective.


This solution used for weed killer must be used cautiously as it is an acid and will kill your cannabis plants if they are exposed to it directly. The best method of using vinegar is to cover your home plant with a cone often used for a dog. This will protect the herb while you spray the weed and only the spots you wish cleared with the vinegar solution. It is best to spray the unwanted weed in the sunlight because the hot sun will dehydrate the leaves of the unwanted weed. Agricultural Vinegar (20) acidity) works quickly compared to household vinegar. Vinegar does not discriminate and will kill any plant, so be careful with it.

Final thoughts

Keeping your cannabis plants free from weeds can be a time-consuming endeavour. These safe weed killer applications are not for all growers. Keep in mind that the home grower who is cultivating the legal four plants will have a better chance to kill weeds and keep unwanted natural plants at bay using these methods than a commercial farmer would. Many of the weed killers approved for commercial farmers are deemed safe, but it is up to the individual to determine what that word really means to them.

How to protect your outdoor cannabis plants from mother nature


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