I used to measure almost everything done to my plants and I've never had any go over double in height and most have come in at less than 75% tho I've heard some do.

There's a fairly accurate rule about stretch time starting from the time you flip 'til you crop. The 40-60 rule.

40% of the flowering time will be stretch and 60% will be bud growth and fattening up.

Thus an 8 week flower will be 56 days x 0.4 = 22.4 days of stretch.

It's pretty damn close in my experience.

With hydro it's pretty easy to tell when stretch is coming to an end by monitoring your daily ppm drop.

As the plants are getting bigger in veg the daily drop should be slowly increasing. Shortly after flipping the drop will begin to dramatically increase. I've observed my DWC go up to a 500% increase in the middle of stretch then stay steady 'til near the end.

A few days to a week from the end there will be a tapering off of the daily drop that will usually end up to be less than what the plants were using at the peak of veg. Mine will stay like that with a very slow tapering off during the rest of flowering.

Another noticeable dropping off of daily feeding seems to occur as the buds are reaching their peak indicating the end is near!

The last few grows I've let 'em grow and not been accurately observant of all the details but after a dozen years you can hardly blame me for slacking off.

Thats a great post man. And accurate in my experience as well. Do you feed your plants transition nutrients during the stretch or are you in full bloom nutes already?

I used to measure almost everything done to my plants and I've never had any go over double in height and most have come in at less than 75% tho I've heard some do.

There's a fairly accurate rule about stretch time starting from the time you flip 'til you crop. The 40-60 rule.

40% of the flowering time will be stretch and 60% will be bud growth and fattening up.

Thus an 8 week flower will be 56 days x 0.4 = 22.4 days of stretch.

It's pretty damn close in my experience.

With hydro it's pretty easy to tell when stretch is coming to an end by monitoring your daily ppm drop.

As the plants are getting bigger in veg the daily drop should be slowly increasing. Shortly after flipping the drop will begin to dramatically increase. I've observed my DWC go up to a 500% increase in the middle of stretch then stay steady 'til near the end.

A few days to a week from the end there will be a tapering off of the daily drop that will usually end up to be less than what the plants were using at the peak of veg. Mine will stay like that with a very slow tapering off during the rest of flowering.

Another noticeable dropping off of daily feeding seems to occur as the buds are reaching their peak indicating the end is near!

The last few grows I've let 'em grow and not been accurately observant of all the details but after a dozen years you can hardly blame me for slacking off.