Every gourd grower has a different opinion on what works best. Some of us fertilize daily with a manure tea. I myself have no time to do this, so using a 10-10-10 fertilizer when planting works very well. Make sure you stay on track for the next application. I wouldn't suggest fertilizing after the 3rd week in August, as this encourages more leaf growth at the end of the season, when the gourds should be hardening off. Remember, you want fruit not greenery.