yellowing leaves on unknown strain help would be amazing

minimum temperature 21.4 centergrade
max temperature 28.6 centergrade
humidity around 50% - 60%
only just put a intake fan on but had fan and outake fan on sinse seed around 26 days old grown under a 250w cfl leaves just started dieing off gradually wondering wether its nitrogen defficiency or heat stress does anybody know what i should do.
thanks.

boym8 said:

wondering wether its nitrogen defficiency or heat stress does anybody know what i should do.
thanks.

Click to expand...

Hey there,

I don't think it's either one.
Here's why:

Nitrogen deficiencies will start with your bottom leaves, gradually completely yellowing them, then will start to work its way up the plant. Your leaves look yellow and damaged, whereas with N deficiencies, the whole leaf will just lose its green color. Literally your leaf will turn completely yellow.

I don't think it's heat either. With heat stress, you'll notice it on the top leaves first, as they are closest to the light. These appear to be in the middle/bottom, am I correct?

Here's what I think it is:

Either nute burn or ph imbalance. Have you possibly overfed your plants? Along with this could be that the pH of your water could be too acidic or basic. If the pH is not balanced, the plant will not be able to get nutrients in the first place, along with being poisoned by acid burn or basic burn. If you use too many nutes, try flushing your plant, not watering for at least 5 days, then gradually add nutes beginning with 1/2 of what you have been using.

Although you very well could have a potassium deficiency.

Hope this helps!

Assuming it's not PH, it looks like potassium def to me. Parts affected by a Potassium Deficiency are: older leaves and leaf margins. Dead patches (Necrosis) can happen on the margins of larger fan leaves thus, the leaves will eventually die off and turn brown.

what is that medium?

using miracle grow expand and grow peat free soil. staight tap water from seed to now which is usualy left to stand in the gro for a day before use. ph is around 7 can't be exact as have one of those 3 in 1 testers for moisture light and the ph.shes enjoying about half a liter once a day but i bought some ph down today as i heard water needs to be slightly acidic is this true .thanks for comments past and future.