How will I know when in almost too late to harvest...

If you want a couchlovk effect then stick with the amber trichomes. Amber trichomes GIVE the couch lock effect while the social side and buzzing effect comes from the white/cloudy trichomes. Preferably and in my opinion you want a 70/30 ratio. I would invest in a jewelrs microscope. You can get them on Amazon for 15$ or cheaper. There you can look at the trichomes with a good view at hand. You'll be able to see the difference between the trichomes and judge it from there. Also depending what day of flowering you are on and what strain you're growing will also help. Different strains give different effects. Do NOT wait too long. Thc degrades once the plant has hit its peak. So personally what I would do is check your trichomes and if its 70/30 give or take it's time to flush/chop. If you cant tell or dont have a microscope, research the strain and see the average flowering time and go from there :) Its all based on preference tho! Many growers will tell you different, you just have to find out what works for you! Best to your Grow- Visions 🌱💨

Based on your pics it looks like you're about ready. Mid October is probably the latest you want to harvest outdoor (most strains are ready late sept, early oct.). Get a magnifying glass and look at the trichomes as stated by others. Some strains don't really turn amber, and by the time they do it's too late for harvest. Generally, the more trichomes which are amber, the more sedative qualities you'll have. But as long as your trichomes are all at least milky white, and especially if you see some amber. You'll be ready for harvest. Another point to note is that proper curing over a length of time, in my opinion, is just as important as waiting for the trichomes. Slow cure in mason jars for at least 3 months and you'll notice a dramatic increase in sedative quality. I'm sure you'll notice as you make your way through it. The stuff that sits longer just keeps getting better.

If you want a good couch lock high go with 20% amber yes it depends on if you have a sativa indica or hybrid. But you bubba Kush will do the trick. Looks to me you can go one more week then chop. Also another tip is to harvest right before the lights come on that day. So you harvest when your plant isn't making sugar and startches. Damn good job though

Couchlock effect has more to do with strain having more indica genetic rather than harvest time; that been said amber thricomes (late harvest) produce a more sedate effect more in line with what you are looking for at the price of degraded THC. There are a couple of signs that indicate the harvest time is approaching: first the would be seed pods (calyxes) swell, then the pistils (hairs) change color to a red / brown, finally they retract, this simptoms happen 7 to 10 days before thricomes been at peak time (white color).