Weed Killer is also known as the herbicide. It is generally used to kill the unwanted wild plants like the broad-leaf plants. The effectiveness and output depend on how you spray weed killer. You can find out a variety of webs to explain how to use weed killer. Here is my personal experience on how does weed killer work?
When you spray the herbicide on the weeds for the first time, it will start yellowing them. It stops the photosynthesis process in them. As a result, the plants do not prepare proteins. So, when these invader plants do not get their food and the required protein for growth, they become pale. The second spray will make them completely dead.
When you spray it to the unwanted plants, you will notice some nearby plants are also getting yellow. It does not mean that you are also killing the desired plants. It is just because these plants were close to the weeds. You will find them turning green once again within a few days.
However, I will advise you to use a homemade weed killer if you want to use near patio or sidewalks. If you are going to use it in the flowering plants or flower beds, just buy a reliable product from the market. It works effectively if you are using the weed killer solution in summer season especially when there is no severe weather forecasting. If the rain starts within its application after its implementation, it will be useless. You should use it on the leaves.
Do not apply it to the top of the weeds. Just the roots and the leaves should be your target. The photosynthesis process takes places in the leaves. As soon as the mesophyll cells on the leaves receive the spray or herbicide, it will start preparing the food by stopping the photosynthesis process. The spray should be from leaves to the roots. The roots are a source to store the food. Gradually, that results in killing them within a few days. However, spraying to the roots can cause damaging some other nearby plants because it can absorb the herbicide too.
If you’ve sprayed weed killer then don’t forget to read this post to dispose of the remaining solution.