I agree with those who think it's bad genetics as well as improper drying/curing as the most likely culprits. I've grown some herb that came out looking like those, really airy and had that same look, smell decent but the taste was nasty. And drying is the next issue, you definitely want to extend the dry time as with good tobacco, there are changes that occur, but moisture content has to be there as well. So when I'm drying I try to keep the temps below 75 F. and the ambient humidity around 60-65% (there are variations on a theme, such as when drying really dense buds, I'll crank the humidity down to 40% for the first two days before letting it slowly creep back up to 60-65%). I always use a fan to move air in the room, but no directly on the buds.
After hanging for close to 2 weeks or more I want the branches to still be a bit bendy, NOT dry enough to snap, and then they go into paper bags (double thick lawn type), under the same conditions for another week or as long as it takes to reach the snap point or close to 60% rH. I like this step because it slows down the drying process which allows more time at the rH range that affects changes in the flavor profile, but also because for me personally, when growing quantities above 2 lbs, jarring can be problematic, and slowing down the curing process gives me time to trim everything without some material at the start being too moist and the last too dry. I've also found that the paper bag tech can be used to extend dry times if necessary, like when you have to be gone for a period of time or some other unexpected event interferes (shit happens ;?). I do this by using an rH controlled humidifier (or humidifier on a timer works) in the room keeping it around 60-65% (this can be tricky and you have to have a handle of how to maintain rH where you want it).
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Also, been growing weed on and off again since the 70's, and I can honestly say that flushing absolutely helps the taste and smoke quality. Done side by side tests along with a dozen friends over the years who all confirmed the results, that to rid the plants of excess nutes, a good long flush is best. Those who pooh-pooh such advice just haven't taken the time to actually find out for themselves or ARE NOT DOING IT PROPERLY, (as in adequately FLUSHING, not just feeding water, but RINSING the medium of nutes) imho. If you use hydro, then it's a matter of flushing it out of the plant itself and that's where the defoliation process come in.
I'm currently running modified Hempy buckets and usually flush during the last 10-12 days, and I'm finding that the more you flush (as in volume of water run through the container), the better. Sure, it can be a messy process and a pita, but good quality herb takes work or iow, if it was easy anyone could do it, lol I find using a large shop vac helps to remove the excess, but there are other ways depending on your situation. Plus beginning to defoliate early in the flushing process, getting rid of all the large fan leaves first and then progressively getting rid of the rest of the leaves so that the plant is forced to use whatever nutrients are stored in the rest of the plant, so that by chop time your girls are mostly naked and leaving little work to do come trim time.