There has been a bit of talk about fertilizing , but what do the numbers mean? Some say an even 20-20-20 is fine, but is it the same as a 10- 10- 10? Or is the 20 just more concentrated than the 10?

I have 3 different plant foods, all with diffierent #'s.

Dyna-Grow Orchid Pro 7-8-6

Schultz African Violet plus 8-14-9

Schultz Orchid Food 19-31-17


I tend to use the Dyna Grow & the African Violet foods only now, but that is only because I prefer liquid rather than the crystal . What do the numbers mean and why are some numbers so much higher?