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Running Metal Halide bulbs into first week or 2 of flower? And..

M

Mrkline006

Member
Read about using MH bulb into weeks 1 and even possibly week 2 of flower to minimize stretching?? Anyone do this? Also, anyone hear of using MH the last 2 weeks of flower? I just seen someone write about it and wondered if anyone has tried? Seems like just a waste?
 
who dat is

who dat is

Cave Dweller
Veteran
Mrkline006 said:
Read about using MH bulb into weeks 1 and even possibly week 2 of flower to minimize stretching?? Anyone do this? Also, anyone hear of using MH the last 2 weeks of flower? I just seen someone write about it and wondered if anyone has tried? Seems like just a waste?
Click to expand...

I'm currently doing it right now with my current grow. My grow light setup came with a 4100k MH and a HPS bulb so I've been using the MH to veg and I wanted to leave it in until at least the 3 week of flower. I don't know if I've ever switched it back out to finish flower out with though. I know the reason being is it supposedly bumps up trichome/resin production but I don't know if I've ever seen any proof of those claims like in a side by side grow comparison.

I'm on Day 6 today and I can't tell if the MH is helping control stretch or not. I definitely overvegged and need to keep stretch to the lowest possible amount though.
 
positivity

positivity

Member
Veteran
Sounds like a great idea. Not much bud growth, just stretch first two weeks.

Maybe makes more sense with a specialized spectrum like a DE HPS. Something like a more balanced spectrum hortilux enhanced not so important.

Something for ceiling height restricted growers to consider
 
hyposomniac

hyposomniac

Active member
I have a de cmh that was advertised as 3100k. But it is not, it looks closer to a 5000k led than my 3000k led (the company all but confirmed)
Nothing stretches under that light... Sssdh, amnesia haze, all under less than doubling in height.
I have a plant that would triple, its more like 1.5x now.

I always over veg. This time I added in warm nights and morning dip.. Very little stretch overall..

The downside is that you get less stack too.. It's not like you get the same amount of bud sites with less internodal space. You will get fewer sites, as well as less internode space.
 
I

I wood

Well-known member
Two of my three flowering rooms are metal halide only, one 1000w and other 600w. Both are for mostly sativa plants but indicas and polyhybrids have done well in both halide rooms.
The predominantly Indica room is 1000w hps & 600w hps.
I like the shimmer and overall health coming off the halide grown buds and quality is what I’m looking for.
Always growing mixed & perpetual I can’t comment on how yields compare with any accuracy but I really don’t notice a difference.
 
S

St. Phatty

Active member
Mrkline006 said:
Read about using MH bulb into weeks 1 and even possibly week 2 of flower to minimize stretching?? Anyone do this? Also, anyone hear of using MH the last 2 weeks of flower? I just seen someone write about it and wondered if anyone has tried? Seems like just a waste?
Click to expand...

My experience is that plants prefer the higher color temperature bluish light of the Metal Halide in the first 1/3 of flowering, the first 2 or 3 weeks when it is mostly leaves & shoots with pistils beginning to proliferate.
 
M

Mrkline006

Member
Thanks all. Glad to see some people have tried it and liked it.. Ill have 4 1ks. Wonder if i could try 2 with HPS and 2 with MH and just rotate every few days or something in flower?
 
who dat is

who dat is

Cave Dweller
Veteran
Mrkline006 said:
Thanks all. Glad to see some people have tried it and liked it.. Ill have 4 1ks. Wonder if i could try 2 with HPS and 2 with MH and just rotate every few days or something in flower?
Click to expand...

Remember to avoid getting your fingerprints or anything else on the bulbs. Keep the bulbs clean for better performance and longer life :yes:
 
R

RockinRobot

Active member
I have always run MH first 3 weeks. However, I recently switched from cheap HPS to Eye Hortilux and with the Eye I don't run MH first as it has way more blue than the cheaper HPS bulbs.

I ran a side by side with the Eye for the entire run in one bay and my cheap HPS with MH first 3 weeks in the other and see no noticeable difference in stretch.
 
f-e

f-e

Well-known member
Mentor
Veteran
I tried the last two weeks, and the yield dropped inline with the lumen drop. Go figure.

I was looking on the phillips lighting site, at general purpose halides. The image of the 400 and 600 looked like a ceramic envelope. It gave lots of useful radiation, comparable to the 315s. I was sidetracked by the 1000w halolux? or something like that. A 1000 watt lamp with greater plant output per watt than anything I have seen. The lumens per watt at 155 was much better than the usual 130 for a 1000, but the energy a plant see's was much more impressive. 2.1 umol iirc. With a 600 greenpower around 1.8 (per watt) The 315 I couldn't compare to, as it's not in the plant section, and was measured with some units I nor google recognised. From memory they may also be 2.1 umol, while 2.3 is the best I have seen from some leds that never came our way.

This opens up the question of which halides. The retrofit ones for son gear are generally terrible. The 315w another league. The latest 4s and 6s seem to of got better, and likely use a ceramic envelope. Why ever not..
 
S

St. Phatty

Active member
Mrkline006 said:
Thanks all. Glad to see some people have tried it and liked it.. Ill have 4 1ks. Wonder if i could try 2 with HPS and 2 with MH and just rotate every few days or something in flower?
Click to expand...

20 years ago (before LED lighting for Cannabis) there was a partial consensus that the mixture of Metal Halide & HPS was what plants liked the most.

I had one set up with 3 ebb & flow trays & 2 lights, a 1K MH & a 1K HPS.

Plants started 12/12 in the tray under the 1K MH, then were moved to the middle tray where they got a mix, during their "second trimester".

Then onto the 3rd tray, where it was mostly HPS, for the last trimester of flowering.

It made a great little production line & the plants loved it.
 
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