Quickest, Stress Free Change From Fluoro/LED to HID?

[Douglas.Curtis]

Over the years I've taken a lot of plants from flourescent (and more recently LED) lighting and put them under HID. I've used all kinds of times and distances for 'acclimating' the plants to the light change.

Have you done extensive side/side testing and come up with the quickest way?

 

[Phaeton]

I went the other way, from HID to LED. HPS to CMH was involved as well. I could ramble all day, I grow just so I can play with expensive lights.

When the plant undergoes a major spectrum change it slows overall growth drastically for almost a week while rearranging all the light gathering structures. The larger the change the longer the stress.
During budding the reactions are different as root and stem growth are already diminished.
Ramble on.
Cold turkey is the way, just swap out the lights all at once. If possible, running the new lights at 75% power the first two days stresses the plant a minor amount less.
Trying to blend the old lights with the new over a period of time slows the adaption time.

As long as the wavelengths the plant needs are present, consistency, day to day, week to week, and month to month results in steady growth. Like people, plants are resistant to change.

 

[St. Phatty]

Never had a problem, but once -

using an 8 year old 250 watt metal halide that looked like it gave off PAR - plants under it sort of went into hibernation. Didn't grow, didn't die. Always thought it would be interesting to have the light spectrum from that bulb analyzed.

As far as problems from transitioning from Fluoro to HID - never had an obvious problem. It's possible the plants didn't like it but adapted without losing momentum in Veg Growth.

I've had interesting behavior from plants taken from metal halide to HPS. The plants would keep growing but look like they weren't digging the color spectrum. One of the reasons I use MH for early flowering. I observe that the Cannabis plant prefers the more white-blue spectrum (higher color number) when it is mostly leaves, as it in early flowering.

 

[Douglas.Curtis]

Appreciate the inputs.

My standard MO is to throw them under the HPS, with the HPS at least 4-5 feet away. I give it a couple hours at that height and then, over the next 12-14 hours, I slowly lower the light.

This time I started with some seriously fugly clones and was only able to put the light 3' away. lol I put in a fluoro and have been turning the main light on for a few hours then giving them a break for a couple hours. Must be ok, I only burned a few leaves a bit. These fugly clones were under a whopping 30 watts of screw-in leds. Not too shabby for a 1k hps change. lol