Container Sweet Potato Soil and Fertilizer advice needed
I am attempting my first container sweet potatoes ever. I have 25 slips of Okinawan Purple already in 3 inch pots coming soon, as well as 24 other slips of 3 other kinds. I have some plastic 55 gallon drums I am preparing as 34 and 18 gallon rubbermaid totes also. It seems I will need to make 400 to 500 gallons of soil total, I liked the Miracle Grow Organic and came up with a possible soil mix I can make myself.
Possible ingredients will be Sphagnum peat moss, aged pine fines (sold as a soil conditioner), and perlite. I had a recent issue with fungus gnat I was able to correct with peppermint tea and less watering, but heard adding charcoal will prevent gnats? From the YouTube video on container sweet potatoes I saw, the vines grow all over like crazy so it will be hard to check soil for gnats (I think). I found instruction on making the rubbermaid totes into self watering containers and wonder if this is best way to avoid overwatering? If above ingredients will work well, can anyone suggest optimum ratio?
I bought some bone meal 6-9-0 and cottonseed meal 6-1-1 to mix into soil for start, and a Neptunes fish and see weed mix 2-3-1 I think I can use weekly when watering? Also, the lady at Steele Plant said she can sell me a 10-20-20 or possibly 10-20-30 (she wasn't sure of exact number) chemical fertilizer the use that came in 4 pound bag for $20 that would do 100ft row. Is organic better route? Or chemical? Any alternative low nitrogen fertilizer recommendations? Thanks for any help!