Many people use homemade soil test kits because they are cheaper than store-bought test kits, but these tests can be inaccurate. One of the most common and inexpensive methods for testing your soil is using homemade ingredients such as salt, water, vinegar or baking soda to make a solution.  Although these DIY tests can work, they are prone to misinterpretation. You may find that you misread the test results and don’t know how much (or what) of fertilizer to apply. Therefore, it’s almost always a better option to invest in a professional soil test kit. That way, you won’t create more work for yourself by adding the wrong fertilizers or amendments.