No, Ohsogreen is wrong. DO NOT use grow big during flowering because it contains more N than P. 6% to be exact. Only in ur veg stage do u use more N than P and when in flowering stage use more P than N. So typically for the first month you can use fox farm grow big etc.. but depending on the...
bat guano high phosphorous, or try fox farm products it seems to work for me all the time. Just remember, more N in veg stage and more P in flowering stage.