Air cooled hoods, a little too cool?

[ballplayer 2]

Hi all. I am using a 600 W HPS in a Daystar AC reflector. Things went alright when when my plants were babies and in starter cells. Now that I have them transplanted into 4" pots, the soil (Sunshine #1 amended with additional worm castings, Fox Farm Ocean Forest, and perlite) is staying wet for too long and the plants leaves are starting to curl a bit.

I have been treating the plants in this area the same as the ones in my non AC setup. That is watering through everytime, with some 10-20% runoff. I was wondering if it might be advisable to give less water to the AC group, no-runoff for the first 2 waterings until some roots get built up in the pots. Then continue watering until runoff as usual.

I have a full grown plant in the same area( 600 W AC area) that did not experience any problems when moved into the area. However, it was grown from seed for 3-4 weeks, transplanted to its final home (5 gallon container) and grown for another two weeks under (2) 400 W Metal Halides (Non AC) until it undoubtedly gained some roots mass.

I would appreciate some input about whether watering without runoff with clean water (pH adjusted, no fertilizer-- fertillizer would be provided by the mix for at least a week or two) would be alright until the plants gained some root mass and foliage to use the water.

I will probably add a little more perlite to the next mix. I cannot improve ventilation anymore right now (265 cfm Dayton in a 5x4 area). Circulation is good, as good as possible without wind burning the plants.

What are your thoughts/concerns? Your help and feedback is very much appreciated.

BP

 

[babylonboy]

Cuttings always lack rootmass, this and small leaf surface gives evaporation problems.

My two cents : the AC room has much lower air temperature and a higher humidity wich automaticaly makes your lady's evaporate a lot less than the non AC area.
I'd say don't water at all for a couple of days.
When the containers are a bit more dryed out just water without runoff and only use pH 5.8 water with some kind of root stimulator or rhyzo's.
If you think it's realy soaked then just repot.

I hope you understand because my english kinda sucks

 

[ballplayer 2]

no problem with the language at all babylonboy, thank you for the reply. I would have never known English was a second language to you. I will probably cut back on the water some, like going without runoff for a week or two; until roots fill the pot.

Or I may just start everything under my intensely lit veg area (non Air cooled). Transplant to final container, let the roots get going and use the Air cooled area as a finishing room.

Anyone else have any other thoughts, or similar experiences using Air cooled lights? I would really appreciate some input about experiences with watering without runoff (in soil especially). Thank you for your time and help.

BP

 

[walt cunningham]

hmmmm, do both rooms have the same air exchange rate? are they the same exhaust fans in both rooms, only difference is one is hooked up to your reflector and the other room isnt?
i usually noticed less humidity levels in the rooms i had air cooled, but i think thats because i had a much bigger exhaust fan in the air cooled room, so the air was being pulled alot more, so that pulled some humidity out.
what are the temperatures/humidity in the air cooled room, and the non air cooled room?

 

[ballplayer 2]

Its not very warm in the AC room, less than 80 F. The non AC room is considerably warmer, 82-84 with a bit better airflow and circulation. I keep the canopy at between 14"-18" below the 400's. I am able to water through with runoff each time I water in the non AC area. Plants typically dry every 2-3 days depending on how well rooted they become, usually very very well rooted.

In the AC room I decided to try to start from the beginning in there to see how things went. I planted clones, and they grew well in the small cells. However, once transplanted to 4" pots they are showing signs of being overwatered. Canopy is kept between 17"-20" below 600 W AC HPS. By the time I get to about 4-6" away there is very little heat, just a touch warm.

I know I should be able to get runoff with each watering. However, the plants take about 4-5 days to dry. I'm certain its too wet. I am thinking no runoff with clean water might be the answer for a week or two upon transplant in this area. Like I said I placed a well established full size plant in this area, and have had no problems with watering through to runoff since the first day it entered the room. Approximately the same distance from the light.

The veg room has the same size fan (265 Dayton), but no carbon filter attached. Flowering room has a carbon filter attached. I am using a 6" Vortex to air cool my hoods separately. There are two Daystar AC's (1 600 HPS and 1 400 MH). I am only using the HPS right now to test its performance by itself (I just purchased it, big MH fan here).

Would it be possible to take the glass shields off my AC reflector, attach a carbon filter to the vortex, and use that fan to exhaust the room and bulb? hopefully improving airflow? I would probably need to cut another passive intake port though.

Thank you for your interest.

 

[dutchcrunch]

Yes, you can take the glass shields off of your Daystar reflectors to add additional heat to the room. I use 8" Daystars & take the shields off when I am early in veg to add additional heat to the room. Although once all 6 hoods of mine are fired up I put the shields back on.

 

[Bud Spleefman]

Is your grow room floor insulated? I had a similar problem when my plants sat directly on the concrete floor, I helped increase the root zone temp by building a raised floor, with 1 x 1s , 1/4 inch plywood sheets on 1 inch thinck styrofoam.... the concrete was like 40 degrees! Yikes!

As also mentioned, increasing the heat in your grow will help, whether by dialing down the air-cooling fans, or opening the glass, etc... you gotta get the root zone warmer, the warmer the root zone, the quicker the evaporation. Obviously, not too warm!

 

[ballplayer 2]

Thank you for the replies dutch and Bud. Very useful information and hypothesis from both of you.

Bud, I am glad you have some experience with a similar setup as me (ie, cooling more than one reflector). So you like to keep the room, and consequently, the root zone a touch warmer until they get well established rootmass. Definitely makes sense. For some reason I thought I could get the roots to expand quickly enough to drink the water and have evaporation take care of the rest of the water. Obviously its a bit too cool, 4-6 days is clearly too long to dry out.

My fear was that the upward thrust of air being pulled through my reflector from the room might damage my bulb, Maybe snapping the base or shaking or something. Perhaps it was a case of me being stupidly cautious, but I did not want to find out the hard way by having the airflow break my bulb or worse. Since there is little/no risk of that happening I will take the shield(s) off and see how evaporation and plant health respond.

Dutch, actually my floors are concrete. However, I do NOT keep the containers on the floor. I have heard how concrete can make root zone temperatures plummet. I have them sitting up on a milk crate plywood table which I can adjust by adding/removing crates, my AC lights are stationary (hard piped AC ducting). When I need to make small adjustments in height I use books underneath the pots.

I know I have to keep the water I use for irrigation purposes of my floor, otherwise the water gets very cold and could shock my roots.

Thanx again for the replies, and helping me with your insight and experience. Very much appreciated.

BP

 

[ballplayer 2]

To make sure I get this straight:

It is alright to take my glass shield off my air cooled hood and pull room air in through my reflector via the fan cooling the reflector? Essentially turning my reflector into a point of exhaust pull.

I know I am probably overthinking this, but I would rather overthink than underthink. Thank you all for your time and help.

BP