A really big thanks for all of this. I am sincerely appreciative of actually getting advise. I am learning that I really don't know as much about Sativa's as I need to and should do more reading on the differences. I now have more things to look over going toward harvest. Your comment about having no leaves when you harvest helped my anxiety level - my other grows - OG's - had amber techs and leaves at finish - so again seeing them going bare except for buds has been difficult for me. Learning about the buds tips and the greasy feeling - all definitely helpful!
Keep in mind that not all Sativa strains act the same. Some only get a few leaves and are very lanky/gangly, while others get a ton of leaves. Most of the stuff that I told you is based on my experience, so it might not always match up to book recommendations. Not all Sativa will lose all of their leaves. If you are feeding them a lot, the yellowing might not be as noticeable. After the 6th week of flowering, I either go with lower doses of a regular blooming fertilizer (not the super bloom type stuff, just regular Loews or Home Depot brand fertilizer for flowers. Depending on how everything looks, I either keep them on reduced rations or withhold feeding altogether. I prefer to see some yellowing as it lets me know that I'm not over feeding the plant and slowly use up the remaining nutes that it has stashed away in it's leaves and roots.
There isn't a right or wrong way to do this, as everyone has their own way to grow. I prefer to keep it simple and basic, while still keeping everyone well fed and hydrated, just not too much! I've attached a photo of fan leaves that are showing the color change I see from the strains that I grow. They are an old strain from Alaska and when finished in cooler temps, such as late fall/early winter, they get a purple coloring to the smaller leaves. It looks like a deficiency, in a way I guess it is, although it is a normal part of flowering. Once I see this color change, I know that the plant is about finished, maybe a few days longer. The 2nd photo shows a better idea of the leaf structure... the fan leaves are pretty far apart, although the buds continue to grow as well as mature. The top leaves, which are clawed, are doing that because the plants are actually taller than the light, and the leaves bend down to catch more of the light from below. The lower leaves aren't clawed because the light level is above the plants, so clawing isn't necessary. FWIW, a fertilizer overdose can also make clawed fan leaves, but they will all be clawed independent of the light source.
