MH bulb vs. HPS bulb

[gromit23]

Hi All,

My set-up:

Puter Cab with 5 Fluoro bulbs: 4@27k & 1@65K w/multiple case fans on 18/6 schedule.
I use this after germination to get the girls growing.

Main grow cab: 17"w x 29"d x 41"tall. Mylar reflecting on three sides, door painted white.
-250w ballast with cool tube passive intake(outside cab) with S&P duct fan pulling thru filter venting outside
-Cool tube hung on pic frame wire able to be moved up and down
-main cab vented thru passive intake once again S&P duct fan pulling thru same filter venting outside
-temps stay in low 80's; Walgreen small humidifier in cab; temp & humidity gauge in cab; 2 small puter fans in cab for air circ.
-running 18/6
-growing dwarf auto fems in soft pots (short rider and green-o-matic)
-soft pots 3 gal.

I am currently two weeks plus in after germination and have just moved plants to main cab. Running MH 250w bulb in cool tube with 27k flouros(4 on Y's) in between pots. I have 3 plants going. 18/6.

?My question is do I need even to run the MH bulb or should I just go strait to the HPS bulb with maybe 65k flouros for extra help?

?Will the 250w bulbs throw enuff lumens with the footprint of my cab?

Thank you in advance...

 

[Hosebomber]

A few things here. First, your ratio of four 2700K to one 6500K CFL's is the exact opposite of what it should be for the seedling/veg state of growth. Secondly, you will need to do some serious training of your plants to keep the plant height down. Stick with the MH and change out those CFLs to something a little more blue in spectra. When you are ready to start flowering change over to the HPS. Read over the link in my signature. It will give you a quick down and dirty on plant lighting. If you have any more questions please feel free to ask.

 

[gromit23]

I stand corrected. I have 4@65k and 1@27k in my smaller puter cab. For growth after germ & Veg.

In my main cab I am currently running a MH250w@65k in a cool tube with a 4@27k flouros on 'Y's on the sides of the plants.

I do have and will switch to a 250w HPS in the cool tube.

After two days the temps in the cab are around 78-79 degrees.

I have just ordered a thermostat temp shutoff.

I am coming up on 3 weeks total for one plant. And it is showing the white hairs on the top.

The other two are a week behind due to germ issues.

I assume it is a good practice to keep a "spectrum" of K in the cab.

I currently have 27k & 65K flouro bulbs-23w.

?Would you recommend the 27k flouros with the MH then flip to 65K flouros with the HPS bulb? The fluoros are strictly on the side of the plants.

?Or a different mix with the MH/HPS bulb?

Thanks for the input!

 

[Hosebomber]

If you didn't have such height restraints, I would generally suggest the 2700K CFL's while using a MH for main lighting to improve the over all spectrum that the plant is getting. However, in your case I would not. Even the small amount of red light from the side lighting of CFLs will cause more stretch then you may want.

 

[gromit23]

Hi Hosebomber,

First off, Thank you for your input.

From the top of my growing medium (FF) I have approx. 24" to the bottom of my cool tube. I was doing more research on this site today and learned that MH will keep my plants low and bushy.

?Should I go strait thru the grow with MH(6500k) only? Should I add any 2700k CFLs ever or the HPS at all?

I currently have the MH above in the middle approx 12" from the plants. I have CFL's(23w) bookending the plants on 'Y's running 1-27k and 1-65k on each 'Y'

Cab temp is staying rite around 80. Humidity currently running around 57%.

?So there will be no issues running the MH bulb (65k) for the entire grow? Even in bloom?

I have a cheap Chinese MH bulb. ?Should I invest in a quality MH bulb?

Once again, Thanks for your help...

 

[Hosebomber]

There are a few people here that have tested different bulbs, that could give you a little more scientific data than I could with respect to the bulb. I personally do not feel that there is $30-$70 worth of quality difference to justify that. I would remove all red light if possible prior to flower, and start LST training it to the bottom of the pot as soon as possible. You can use MH lighting all the way through the growth cycle and some auto growers swear by it. I've never grown an auto so I can't give you personal experience in that case. You realistically have about 18" of grow space. Even for dwarf plants that is very short. Training your branches to the bottom of the cab will give you room for 12" colas give or take. There are some great tutorials on LST training on the site.