Research what nutrients you are looking for. You dont need FF nutes to have a sucessful grow. Blood meal and bone meal are great nutrients for soil amendments, so is bat guano, and molasses. If you are buying soil or perlite or nutes, just walk into the store and tell them what you want. Period. They dont need to know you are growing "tomatoes". Dont ask questions at the store. Pay with cash if using a cc bothers you. Farm stores are a great place to find grow supplies at low cost.

The last time I bought supplies, I told them I wanted a bale of promix, 50 peat pucks, and a big bag of perlite. They got my money and I got my grow supplies. No questions asked. And the promix was cheap so I was really happy.

Check out grow forums for plants other than weed. You are not the only one buying nutrients to grow plants. Or soil for that matter. I hope this eases your mind a bit. Try to find yourself a special flower or plant that you like thats not weed, and learn how to grow that too. You will learn a lot from growing other plants too.