Nute burn or heat stress?

[Kahn]

I got some dicoloration on the tips of several plant not all though? I am running Dionized straight water now and hopefully in a few more days I should be able to control the room temp much better. Alot of the bottom leafs are also yellowing and dying I assume this is just due to lack of light and is not preventable ? Can anyone tell me if i have something more then nute or heat stress going on ? Thank you in advance. Please help getting to be a pretty expensive endevour for a few plants Using a 400 W MH/HPS running MH for veg and a 90 watt UFO, DWC/AREO system (rainforest 66). In a 4x4x6.5 tent. This week will be moving in to a 6 x 3.5 x 9 foot room with a portable air conditioner for climate control.

 

[Kahn]

For the most part they seem rather healthy and are growing very fast this is 5 weeks from seeds. I would like to fix any problems with them while they are still preventable if possible.

 

[SweatyC]

They look pretty healthy to me. The burnt tips may be from nute burn. As for the yellowing and dying leaves, check out: http://www.icmag.com/ic/showthread.php?t=11688

 

[Kahn]

Thank you that is a great guide and I just bumped my light up again and hoping that will do it i will add 50% of the recomended flora series nutes in another day and see how it goes.

 

[UserFriendly]

Nute burn is heat stress..... when you understand how water and salt concentrations work through osmosis, and combine that with a plants ability to evaporate water for cooling, you'll know what's up. That's what's up. I wouldn't worry too much; those plants are healthy enough to get you a good harvest.

 

[aknight3]

heat stress also causes more curling of the leaves, u have slight nute burn im not sure about what userfriendly said but they look good i wouldnt worry about it

 

[iloveit]

Nute burn is heat stress..... when you understand how water and salt concentrations work through osmosis, and combine that with a plants ability to evaporate water for cooling, you'll know what's up. That's what's up. I wouldn't worry too much; those plants are healthy enough to get you a good harvest.

I have a quick question: Every day the PH in my res rises so I add PH down, Ive heard when applying PH down the res should be topped up because build up of PH down can affect the plants is this true?

 

[Kahn]

Thank you for all the feed back.

 

[UserFriendly]

I have a quick question: Every day the PH in my res rises so I add PH down, Ive heard when applying PH down the res should be topped up because build up of PH down can affect the plants is this true?

PH- is usually either nitric acid (nitrogen) or phosphoric acid (phosphorous). It actually feeds the plant. Keep your EC where you want it and don't worry about anything else.