In one sentence, describe what the following article is about:

Deer can eat to within about 3 feet (0.91 m) from soap. Calculate the circumference of a circular border around your trees and plants that is at least 3 feet (0.91 m) away from them. Use 1 bar of soap per 3 feet (0.91 m) around this border. For example, if you have an 100 foot (30 m) border, 100 / 3 is 33, which is roughly the amount of soap bars you need—each spaced 3 feet (0.91 m) from each other. You can also use 1 bar of soap for every 10 feet (3.0 m) if you don't have lots of deer activity near your home. If you're going to apply liquid soap, you need to apply approximately 0.068 ounces (2 mL) to the stem of each plant and tree. Count the number of trees and plants within the area you need to protect and multiply the number by 0.068 (ounces) or 2 (mL) to get the amount of liquid soap required. If you count 25 trees and plants total, you need 1.7 ounces (50.28 mL) of liquid soap. This is derived from animal fatty acids and is the repellent. Go to your local grocery or drugstore and find the personal hygiene section. Locate bar soap or liquid soap and make sure the ingredients list contains tallow (also known as sodium tallowate). Depending on the extent of your deer problem, you may want to purchase bulk packages to save money.  Always select the strongest scent possible to increase the soap's deterrent effect. Don't use soaps that contain coconut oils—they might attract deer. Most soaps have ingredients that can either damage soil or alter its pH of and destabilize the environment for plants. Try to avoid soaps with salt and sodium compounds, boron, chlorine bleach, and alkaline compounds. Don't worry if some of these ingredients are present—just do your best to avoid as many as possible.

Summary:
Determine how much bar soap you need. Calculate how much liquid soap you need. Purchase bar or liquid soap that contains tallow. Avoid soaps that contain soil-affecting ingredients.