Cuando dejar abonar coco

In your diary you mention that it's soilless medium, so looking at it, i assume it's peat or coco, is that right? In this case i would start the flushing with water about a week before harvest. If it was soil i would say 2 weeks, if it's pure hydroponics (so the roots hang into the water) maybe 2 to 3 days is sufficient. Looking at the tip of the leaves they look burnt to me, as if you fed too many nutrients, how many nutrients do you give them when you feed them? It might be a bit too much. Maybe a bit less nutrients per feeding schedule would be better, but check the tips of the new growth, as the old leaves will not recover anymore. If the new tips don't show this, don't worry about it. Other than that this plant looks good! Still has a few weeks to go, but look at the trichomes for checking when they get ready.