When to begin flushing before harvest

Sounds like they're real close to ready. I'd start the flush now. Check trichs again after a week. If there are still clear trichs and not a lot of amber, continue to flush. The plant should start to consume lower leaves and the buds should become ripe. During the 2nd week of flush, if it goes that long, trichs should be all cloudy with a few amber, maybe 10%, but mostly cloudy.

 

Flushing Plants Before Harvest Is Unnecessary says Rx Green Tech

CONCLUSION
In a first of its kind study, Rx Green Technologies evaluated the effects of flushing period on yield, potency, terpenes, mineral content, and taste characteristics of Cannabis flower. Overall, the length of the flushing period did not impact yield, potency, terpenes, or taste characteristics of Cannabis flower. Taste test results indicated a trend toward improved flavor and smoke quality with the zero-day flush. While there were no significant differences in nutrient content, there was a trend toward increased iron and zinc in flower flushed for 14 days. The results of this trial indicate that there is no benefit to flushing Cannabis flower for improved taste or consumer experience.

 

New Research Shows Flushing Plants Before Harvest May Be Unnecessary | High Times

This debate has been going on forever.

There hasn't been enough testing to determine anything without a doubt and this one study doesn't really prove anything. Just because you buy into it without any real scientific data to support it doesn't mean this one study has conclusively proven anything except that it agrees with your personal opinion and this all boils down to personal preference, the techniques and levels of how much nutrient a grower is using and how well a grower is able to dry and cure their product. You can grow the most amazing plants ever and they could still be shit if you aren't drying and curing correctly. There are so many variables that can't be accounted for because every plant will be different from every other plant grown from different seeds.

From the article: "Wedryk says that while she doesn’t think that cultivators should overhaul their practices based on one trial, she does believe that growers should be open to trying new things.

“I would definitely recommend that growers play around and find what works best for them. I talked to a grower at the event who doesn’t flush and he’s perfectly happy with his product,” explains Wedryk. “Everybody has their own unique system and there are so many different components that go into growing. What works for one grower because of their unique set of circumstances might not work for the other grower.”

Danko agrees, noting that growers who are careful not to use too much fertilizer may need little or no flushing time for their plants.

“Really, flushing is an extension of the fact that most people are over-feeding their plants,” says Danko, advising growers to feed their plants lightly, in many cases at lower levels than recommended by nutrient manufacturers.

“It’s always easier to bump up the nutrients when you see a deficiency than it is to remove nutrients when you’ve overfed,” he says.

Although Danko still recommends that growers flush their plants prior to harvest, he supports efforts to examine commonly held beliefs in a controlled scientific setting. Wedryk agrees, explaining that “as more and more research comes out in cannabis, I think we have to question some of the things that we think we knew and see if these still really hold or is it a new day?”

Seed to seed of the same strain will result in many different terpene profiles, flavors, smells and THC levels. Also, there is no data about the process for curing that was used. At what level of moisture content was each plant removed from being dried and then put into jars? How often and for how long were the jars burped and what time period was allowed for the entire cure? There is no data on the chlorophyll content of each cured plant before and after the cure?

One thing I noted is the higher levels of iron and zinc in the 14 day flush, which they say both are used by the plant to break down chlorophyll, which is what the curing process is supposed to be doing. This suggests that more chlorophyll will be broken down in the resulting buds. Chlorophyll content is the component responsible for a rough smoke. The cure is the process for breaking down that Chlorophyll and removing it.

Something I saw on the positive side of flushing for the last week or two. The article says "Lab analysis found no significant differences between the different flushing treatments for flower yield, THC potency, or terpene content." This is interesting. If there is no difference in these things, then the only real difference and a positive in favor of flushing is that you are not wasting nutes and therefor you are saving money on the grow.

I suggest the OP do what feels right for them as far as flushing versus not flushing and invest more thought and effort into correctly drying and curing the yield and to not over dry or rush the cure.