Now this is probably a dumb ass question but I need to know the answer so I can start my first grow. I have 15 x 5 gallon cloth planters I'm going to use. What do I put in it for the plants? If I put nothing but fertilizer in it it's gonna be expensive af right? Like what other dirt can I use? If you could please link me product from Lowe's or Walmart that's the cheapest and get the job done. Thanks!