Ventilation and plant stress vs light quality

Hey y'all, first grow, first post, lurking for a while gathering info, and it's time to get into the mix. Some might say my goal is a little bit ambitious being a noob, but i'm pressed for time and need to make some medical cannaoil.

First, my question - what's the better trade-off for good grass.. cool tubes (winged reflector type) with reduced light output, or bare bulbs with overpowered fans stressing the plants with too much moving air ??

Here's my plan for grow room size and spec (in the beginning i was planning 2x 600w HPS, but then i realized i could get more bulbs in there, closer to the plants WITH a better spectrum mix, and more 'useable' lumen/PAR ouput):

- 1.2m to 1.3m W , 1.8m to 1.9m L , and 2m to 2.3m H (actual total length will be a little more for a clone/mother chamber)
- 6 plants
- 2x 400w dual spectrum HPS horizontally
- 2x 250w MH hanging in between the six plants
- Ventilation : this would be the question mark

So it comes down to the main question from above. I'm not sure as to which option is best/healthiest for my plants. I could go one way and put the 400's in series in cool tubes to keep temps down, drawing air from outside the grow room for them , and use a second small fan for the normal 1 to 2 air changes per 5 minutes .. or i could go the other way and leave bare bulbs while using strong ventilation to clear the whole grow chamber. The 250's i plan on leaving bare.

What do the more experienced have to say??

Next to that i'm not sure if should use both 250's for veg or one 250 together with one 400, before turning them all on for flower.

Any advice much appreciated.. i'm open to options!! One idea for example was to use normal winged reflectors and put holes in the tops where small fans would directly extract heat, IF someone could confirm that that would be effective for keeping total ventilation size down as to not stress the plants.

Get the cool tube

Are you growing in a basement, addict, or house room?

Ask yourself a few questions, how much electricity will the extra fans use? Will it increase your cost? Fans blowing on plants isn't a bad thing, it mimics the outdoor wind, thus building a stronger plant. However too much wind resistance can hurt.

I have down it both ways, and I will be honest I had Excellent results hanging the bulbs. However for that grow I didn't have to worry about heat. I still got good results using a batwing reflector but I must admit I was very impressed with the hanging bulb method.

Also think about this, cool tubes wont provide air circulation, fans will. Cool tubes are great though. I am not knocking them.

I think its really a matter of personal preference and of course your growing situation. As for your question about what lights to use during veg, I think the 2 250's together would be fine. Also will decrease the amount of heat. If you find yourself needed more light you could always remove a 250 and add in the 400.

Open bulb is fine till you want to expand..when you have multiple lights cool tubes are essentially a must in order to evacuate the hot air out the room and keep reasonable temps..the amount lost from the glass is minuscule if kept clean

qwizoking said:

Open bulb is fine till you want to expand..when you have multiple lights cool tubes are essentially a must in order to evacuate the hot air out the room and keep reasonable temps..the amount lost from the glass is minuscule if kept clean

Click to expand...

True. If you had many open bulbs you might even have to run a air conditioner.
And thanks qwizoking, you just gave me a idea to write about. Lots of people overlook the light loss from a dirty bulb. Thats a good quick topic to write about.

Thanks for the quick replies! It's going to be in a house room. Current temps in the mid to high teens, sometimes less in the winter with the window open, and mid to high 20's in the summer. Ventilation is going through the chimney. The reason i'm thinking of making the grow room/box taller is because of heat actually. Electricity for fans and such isn't a problem.. building a quality grow around 1300w of HID is primary.

Kratose, if i need to exhaust air a few times every minute or two i'm not sure how much that would negatively affect the plants.. in any case, an oscillating fan would be used primarily to keep the plants dancing.