labifleanswered grow question 6y ago Hey gardener! A lot of people grow like you because electricity is cheaper at night and the temperatures are lower, so if you have an HPS lamp, itâs perfect for maintaining a good temperature. If you only have a few degrees of difference, donât worry, but be careful not to have higher humidity during flowering, and if you can, try not to exceed 28 degrees; that would be perfect. So maybe you can add a fan, even though I donât think the temperature will drop by much. Good luck to you!