your flowering start really depends on two things... your latitude (you can find the flower chart on my journal), and when the sun really becomes visible in the sky, and really hidden behind mountains/horizon when it sets. Direct light is relative to its photosynthesis, transpiration, and other things (like fluid transfer rates etc.), once the sun is up, its light reflects off of all kinds of things in the atmosphere and on the ground, so once the sun is up, they are getting light, just not as much as direct sunlight. Purples are predominately Sativa! Not indica. I have grown many many kinds of Sativa's and purples. Indeed I have three different kinds of purple growing right now, and they are all staiva dominant strains! GDP does have more indica in it though... just look at the actual buds when they are done to get a good idea of what I mean. Sativa's could flower for up to 15 weeks, indicas as little as 8 weeks. It depends on Trichromatic development, density, and frost (unless you feel like putting a heater out there). The best kinds of music to play are alternating R&B (for getting rid of spiders, yes it really does work if the sound source is close enough to the plants and directly on the ground) and fast Rock (for root stimulation and increasing plants vigor, this is scientifically proven), also, buds are denser and a little darker in color if you play classical at night (for some unknown reason). Harvest time really has very little to nothing to do with planting/transplanting time (unless you are growing ruedialus, those are self blooming, on a timeclock so to speak), it all depends on amounts of light and the quality of environment/care they have. Mine, I expect, will be done in October as well, maybe Cinderella in late September, maybe Super Skunk in early November. When growing different strains, there are often different harvest times (this seems the case for you), so get a good magnifying glass and check on trichromatic development starting in the last few days of the sixth week of flowering. You can tell when flowering starts because instead of having spread out white hairs (pre flowers) you will get tightly bunched groups of hairs (hairs are called pistils, the female pollen collecting part of the plant). Pulling up all the grass there will help keep bugs away and keep the humidity down during flowering. Mulching with sticks etc. will help to ensure fewer unwanted weeds sprout, keeping moisture in the soil, and help moderate the moisture in the air during flowering (simply remove the top layer of mulch). Hope that answered some questions....