Hey Growmie, 70-75 days is typical of the flower time necessary for most autoflower strains. There are definitely some outliers there, but knowing you are growing the Blue Dream Sherb Auto, it should be between 75-80 days depending on how dialed in your environmental conditions are. When the pistils turn orange/red then brown, and you notice the buds aren’t swelling anymore, your getting close. A jeweller’s loupe would go a long way in harvesting at the optimal time. Happy Gardening !❤️🇨🇦👊