To be honest, i just give them lotsa love and i fertilize once a week. Once the spikes are yellowing and the majority of flowers have already fallen off i cut the spike. every new growth will spike one it's mature... at least that's what my Sharry Babys do.
I use 2 parts 20-20-20 (Nutrex) with 1 part bloom booster. I've been using it for years now and it's never failed yet.