How much time until harvest?

Start thinking about harvesting when the plant has 90-95% brown pistils, this will give you buds with the most amount of THC and give you a mind bending head high. If you prefer a more sedative, CBD influenced body stone, harvest when there are 98-100% brown pistils. This is the easiest and best gauge of when to harvest, not all plants will get amber trichomes, other will have over half amber trichomes after only 4 weeks of flowering, it all depends on the genetics of the plant as to whether or not they get amber trichomes. Waiting for a strain that never gets amber trichomes to attain the oft quoted "magical" figure of "30% amber" can result in people harvesting over ripe, near dead plants with extremely degraded cannabinoids. Remember too, flushing does not mean drowning your plant with vast amounts of water, it just means giving normal amounts of plain water for a few days before harvest. The idea is to remove any nutrient salts from the fertilizers from the plants cells, not drowning the bejeezus out of the soil/substrate. The idea being that the plain water removes or "flushes" the salts out of the cells of the plant, enhancing the flavour of the buds and there is no need to overdo it with the water. Too much water/drowned soil can lead to over hydrated buds that can then be susceptible to bud rot, especially during the drying process. Hope this helps, Organoman.