I'm on my third run with it... have done the 20 day defoliation today. I was making a timelapse but the damn camera couldn't handle multiple gigabyte movies and kept crashing after about 5-6 days so I gave up.
In a nutshell it can hurt yields if not done properly but done well the yields and quality are great (1900g from 1200w of COBs on the last run and I'm still figuring it out as I didn't actually buy the book). The timing of the defoliation is strain dependent IMO. You need plants vegged longer before you flip to flower than if you were not defoliating. You also need to be selective about defoliating the smaller fan leaves. I think I have it sussed out but I can't say for sure until this run is done.
Give me 4 weeks and I'll post up some finished pics.
Before and after 20 day defoliation pics attached... (excuse the small plant in the front Right, it wasn't ready but I had a space to fill so it got flowered anyway)
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