Some help, please, one of my plants is withering

i used this system : and all was good.

Yesterday after reported them, one of the plants started to wither

This is my setup :
3 X 250w mercury lamps at 10 inches from the top of the plant.
temp range 80-95 fahrenheit (25-35 celsius)
18 hr light cycle
6-3-3 NPK fertilizer
10 oz (300ml) of water once a day (not during the light cycle)
humidity 25-50%


The plants are 1 month old, and they were developing like twins. Now the one on the right stopped growing.
The plant on the right, the one that is dying had a very well developed root system.

Any help would be much appreciated ! What did I do wrong, how can i fix it ?

Your temps are too high. I would move the lights higher and get better ventilation. Plants will also suffer a little transplant shock so you are likely seeing that too.

Thank you for the swift reply. I have good ventilation, ( 3 stage - 200w exhaust fan) if i increase the power on the fan, the humidity drops under 20% (with the humidifier at full power) , but theres not much i can do about the temp thou... its 90 F (32 celsius) room temp (95 outside - 17% humidity) over here (eastern-europe) . She's getting worse with every minute...

Your temp is too high for babies that size... 750 watts is overkill for 2 small plants, and it is only driving up your temps into the unsafe range... unplug two lights, and center both plants underneath the middle light. Throw the light on 24/7 until they recover and start growing again, then switch back to 18/6. Also, move the lamp 12 inches away from the tops. If the ambient temp is 95 in the room, what do you think the temp is 10 inches below the light? it is more than 100 I bet.

I have done incredible things with the just a 150 watt HPS, so I know I am right about this, and I hope you are listening.

as everyone is sayin your temps to high try bringin it down to between 25-30 C that should help

peace out

i followed your advice, left just one lamp (i was using 3 lamps not because i want them to grow faster, but i'm trying to compensate the fact that they are mercury lamps not sodium ones... and they have an average lumen output, aprox 5500lm ) your 150w hps probably gives out about 15.000 lm right ?

the temp is stable at 83 now.

it seems that the plant on the right is not getting any better (or worse) .
The one on the left however is really really happy , ill post a pic soon.

Are you sure about the 24hr cycle ?

Very good my friend, and you are correct. The 150 puts out around 15,000 lumen. I found mine on Ebay for approx $100. you could still vegetate them with the MV light, but I would consider an HPS once you get ready to flower. You could do more with a 150 watt HPS during flowering than you could with all three of those lights blazing. If I remember correctly the light spectrum from a MH or MV light is in the blue range, whereas the light spectrum of HPS is in the red range. Plant life benefits more from light in the red range if you ask me. I use an HPS for the entire growth cycle form veg to flower, and I have not been disappointed. There has to be a balance between the correct light and ventilation. you should exhaust hot air from the top of your structure or room and suck in cool air at the bottom. Heat rises and your goal is to help it leave the room faster by exhausting at the top. in my current setup I used the 150 in a homemade box about 4 feet tall. During flower my girl became so dense with flowers I had to take string and tie down branches to spread out the canopy so the flowers had room to develop. when the light is on, the top of my canopy doesn't get above 90F and the ambient in the box is always around 80F. When the light is off it goes all the way down to 70F because my room is air conditioned by a window unit, and my box has active ventilation situated in the manner I described, via two powerful computer fans.

Maybe this gives you an idea of what direction to take with your setup. write back and let us know where you're going with it.

About the 24 hour cycle: Yes I veg clones and babies under 24/7 light... The 24 hours of light kicks the plant into overdrive and they just explode with growth. It all depends on how fast you want them to grow. 18/6 is perfectly acceptable and may save you some money on power. you can flower plants with anywhere between 12 and 8 hours of light. Initially I set the timer at 12/12. now that I am 6 weeks in I have set it to 11/13. during the last couple of weeks I will probably go to 10/14. its been said that shorting the photo-period during flower will produce more resin. However, you should be the judge of what works for you through trial and error.

You are perfectly right ! the MV lamp is in the blue spectrum 3400k . I got inspired by your setup and came up with this rigging (as opposed to having the 3 lights just dangling and a fan taking air out).

Things were looking worse and worse for the little one, so i repoted her into dry mixture, didn't water her for 30 hrs, left the light on 24hrs, and now she is recovering !!!
Thank you !

For now, my goal is only to keep them into a vegetative state, but i checked out a local hardware store and found HPS lamps ranging from 125-600w, so i'm considering switching to HPS soon. The electric bill is not an issue, the temp however is an issue, since this is a closet grow and theres really not much cool air going in.

So, all in all, it seems that either it was a soil problem (i can't measure soil ph since i dont have a tool for that ) or an over-watering problem combined with hight temp.

My advice to anyone trying to grow "white widow" is to think twice !!! , the plants are really sensible to climate changes ! This is my 3'nd grow (first 2 were ak48 ) and its the first time i'm having this kind of issues. Also it seems that the plant is developing really slow ( you are looking at a 6 week old plant )

And still... i have no idea what is wrong with her...
She grows for a couple of days then she just drops... could it be bad genetics ?
The soil is the same , the ph is the same... i'm really clueless at this point ...
Her sistes is doing just fine ...

i also went 400w HPS thank you stealthgrowing !