Is there more then one sign to tell when its time to harvest

[justcause]

Indoor - soil - 600 HPS in their 10/11th week of budding and no sign of amber anywere on my girls.

room temp goes from 76 down to 70
RH is around 55
sativa 3.5 tall 4.0 round flowers 7 to 10 inches.
Ph 6.2 to 6.4 nothing has changed at all in the room or enviroment.
just using a ripe nute and this is the first grow indoors for me.

is there any other way to tell if and when I can start the flush cycle the hairs are turing amber but not even at a 50/50 ratio. no real issues with the grow up til now 11th week and Im not sure how much further to let them go.

does anyone have any ideas

 

[1970s Grower]

I have found that when the plants stop consuming thier historical water usage, they are 7 -10 days from ready.

I weigh my plants before and aftter each feeding. I log the results. This has never failed me.

The only other way a plant will consume less water is if its got nute lockout or nute deficiency.

Looking for amber trichomes is the only fool proof way though.