Q.Planting herbs
If you have weeds to remove where you want to plant herbs, is using a weed killer a bad idea or should you use something more organic to kill the weeds? Would the weed killer have too much chemicals in it to plant herbs after you kill the weeds and will it harm the herbs at all?
There are many schools of though on the use of herbicides in the garden.
If you are wanting to use the Herbs for culinary use, I would recommend against the use of these chemicals.
Here are several articles that will help you decide the best course of action for your situation.
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/how-long-does-weed-killer-last-in-the-soil.htm
https://www.gardeningknowhow.com/edible/herbs/hgen/growing-organic-herbs.htm
https://www.gardeningknowhow.com/plant-problems/weeds/using-herbicide-in-gardens.htm
https://www.gardeningknowhow.com/special/organic/weed-it-and-reap-how-to-make-your-garden-more-appealing-without-chemicals.htm