it's been growing under 250W HID in a 2x2x4 (ft.) cab, since it was a seedling, temps have been up to 90+ for about a month, now all of a sudden I move the direction of the cab so the vent is directed towards the bedroom to lower temps., and then I add a window AC last night, right infront of the door way and lowered temps even more.

now, leaves are turning yellow and brown. it just happened overnight.
I'll post pics later.'

they used to look like this

[Sleepy]

what are you feeding it?

how much & how often??

what is your water's pH???

what is the pH of your runoff????

is the plant rootbound????

got a current picture? can you post another picture under white light?

how tall is the plant?

how close is it to the light?

what are the temps now?

what did you do on the afternoon of february 27th???

Originally Posted by Sleepy

what did you do on the afternoon of february 27th???

I like how you tthrew that one in there

Heres a few questions that might help

How many plants?
Seeds or clones, source?
How old are the plants?
How big are the plants?
Lighting wattage & distance?
Soil? (ingredients?) or hydro system? (Res temp and PH?)
Container size?
Watering frequency? How do you judge this? PH of water going into plant? Ph of run-off?
Fertilizers used and how often?
What size Room/Cab are they in?
How do you ventilate the space?
Other details? Include photos if possible.

here are some current pics although they were from a phone camera I gotta wait until next week to get a digital camera.

in the last 24 hrs., the only thing I did was add an air conditioner to the door way, it's been in the 90's+ since seedlings and now it was around 74 at night. I had to return the AC since it was supposed to be portable but ended up being a window unit which isn't allowed with our apt. complex, but now temps with light on are 85 max.

The plants are in Fox Farms Ocean Forest, and last week I added Grow big, at half strength then in the middle of the week I added regular distlled water. this morning (after (not before) leaves were yellow/brown), added grow big and big bloom at full strength.

I only add nutrients once a week, since ocean forest is strong as it is, container size is 1.25L plant is about 4 weeks old.
These were fem. seeds.
Plant size iincluding pot is about 10"
Lighting: 250W MH, they are 1' away from the top of the plant

PH is done by a ph control kit, I adjust PH Up/down accordingly to the chart
water frequency is done by checking all around if soil is dry 3/4" - 1" below, and I water about 3 times a week. Nutrients, once a week.

cab size = 2x2x4' (ft.), air is exausted through a 4" vortex, and it's right next to the doorway, vent is pointed towards the bedroom, to allow fresh air into the cab from the vent. there is a 16" osicillating fan outside the cab (in a closet), and a 7" fan inside the cab.

like I said only thing in the last 24 hrs. I did was add that window unit AC, I didn't change anything else, didn't water, change height of light, didn't do anything.

here are some pics., but they're from a phone camera, I'll hopefully have a digital camera in a few days.














this is what they looked like before I added the AC less than 24 hrs. ago:

I just checked the plant it's getting worst, yellow and brown spots are going on the top of the plant as well, although since I watered and added nutrients this morning I've noticed leaves aren't drooping. You can't see from the pics, but there is definately some brown spots on leaves, I'm going to try to borrow a digital camera ASAP. Do you think it could be because of humidity? my humidity is at: 26% - 85 degrees, I know this is very low especially for veg., I'm going to get a humdifier, also is there a difference between a humidifier and a de-humidifier?

here are more pics but it's hard to tell with camera, in the last pic you can see a little bit of that brown spots i'm talking about

my guess is that it's from nute burns, I can't think of anything else I'm going to stop adding nutrients for the next 2 weeks and then flower, what do you think? the AC thing is probably just a coincidence

[ChaoticEntity]

hmm feeding once a week, the tips look good so I don't personally think it's nute burn. What I'd be willing to bet is that the PH is off a touch and a lack of P.

unless your water is really hard and the PH is over 7.5 or under 5.9-6.2 I would leave the PH change out, often times the PH chems cause a lot of salt buildups.

What I would personally do it water with plain tap water and let 8-12oz runoff, more if you can, wash out that soil a bit. I would also feed it 1/4teaspoon per gallon of epsom salt(grow big has none and it helps the plant uptake other things like P) I would also get some bat guano tea that high in P and give it a dose of that if you're going to feed once a week. If you don't want to use a tea I would recommend 1/2 strength nutes at least 3 times a week. To me it looks like they need a bit more food.

[BaffledMonkey]

I think it needs a dose of micro nutes and a repot, check if its root bound

[Blackmelo]

Interesting. Never seen this before but I am suspecting it to be linked to the increased airflow. Increased airflow will mean increased transpiration and since you are in the most dry place I have ever heard of already...

Originally Posted by MynameStitch

When your Relative humidity is low, you can almost bet your going to soon get a potassium deficiency from your plants perspiration.

So try to increase humidity. Cheap way of increasing humidity is placing lots of wet towels and buckets filled with water in the room.

You definetely also need to check the ph of the water you are feeding your plants to make sure your ph is ok like mentioned.
Cheap ph testion liquid will do the trick and maybe some ph up & down if needed.

Dehumidifiers lower humidity by removing moisture from the air, humidifiers increase humidity by adding moisture to the air.