Humidity and deficiency issues.

[dw1]

Hello AFN, I've been growing autos for a few years on and off and always seen to get deficiencies during flowering. I'm growing photos now and still getting same problems.
My set up is now a 2x2x2 monster tent
4x 600w goldstar cool shade lamps with the digital ballasts.
6"ryno filter and 6" rvk intake pulling in cool air from my loft.
I've only got 3 lights on at the moment but my temps are still in the high 80s and my RH is down around 20. I'm worried about turning the 4th light on when the time comes and think I'm just going to need to get a bigger intake.
I was feeding with the bio range, veg, bloom and top max. Call,mag but I'm changing to green dream now. The plant I'm worried about is a skunk #1 and in its 4th week flowering, it's on 2.5mil of bloom per ltr, a mil of top max and a mil of call, mag. It has got leaves burning up around the top. And seems to be a common problem for me when my plants are blooming. Hope I've given enough information for someone to be able to help me out. Thanks.

 

[briman]

If its burning up, your lights are too close. Place your hand right at the canopy. If its too hot for your hand, its too hot for your plants. You can also cool things down with a speed bully set up on your extraction, by turning the dial up and moving more air through the grow room.

 

[Nabzter]

To raise your humidity leave a bucket of water in the tent or even a dish or something. In terms of lowering your temps the only solution I can think of is to raise your intake and/or output. 3 600w seem alot to me in a 2x2 imo 2 x 600w is just fine. Or maybe you could swap a couple of lights out for LEDS as they run alot cooler.

Also could try raising your fan so it's blowing right above the canopy and keeping those top colas cool.

 

[dw1]

I thought of that and moved it further away, it's about 15" below the light now, I can't get the any further now cos the lights are as high as they go. I'm sure I've got heat problems but definitely a deficiency as well tho. I'm not sure if I'm over feeding or under feeding. Thanks for the reply by the way chap.

 

[dw1]

I've got a bowl of water in there, think I'll change my bulbs for 400s and get an 8" intake,if that doesn't work then God knows lol. Any idea about nute deficiencies at all guys?

 

[Nabzter]

That yellowing could be a nitrogen def. where on the plants is it starting ? Also is it spreading from the leaf tips ?

 

[dw1]

And I thought a 600w per square metre was about right no?

 

[Nabzter]

Depends on the number of plants and your capacity to handle the heat. I use a just 1 x 600 in a 1.2 x 1.2 space and get great results

 

[dw1]

It's starting at the top so don't think it's an N deficiency. I think it's a mag def but I don't know if it's over fert or under.

 

[late]

2x2 is about 4 square feet.

A rule of thumb is 50 watts/sq foot...

Try running one light for a while. My tent is about 8 sq, I run a 400 watt hps, and it's fine. This should also help with the temp, which you should monitor.
I have this thing, it's about ten bucks.
AcuRite 00613A1 Indoor Humidity Monitor