Im growing in 5 gallon buckets this year some cucumbers, broccoli, roma tomatoes, carrots and lettuce. Ive already blended some miracle gro potting mix with a few buckets of nice black compost from my leave piles. Just wondering what else i can do t better the soil for thw different plants so they individually grow better? Ive heard people says egg shells in the tomato soil exc also is there a general fertilizer ill be able to use on all these veggies?