Hello mates hope you can help me
These are my automatic critical XXL on 7 lt pots
Under a 160W led on a 80x80x160 growing tent
Been growing for six weeks on a 18/6 cycle
Watering with tap water may have been my mistake
Been fertilizing under label instructions
I want to know if this is a Potassium deficiency or any kind of excess
What do you suggest
Thanks to all
It looks like nutrient burn to me. The discoloured tips scream that. Also as the plants produce flowers the very bottom leaves with die off which is normal.
This could be that very thing but I am no expert on Deficiencies. 
Also if the bottom leaves are touching the soil, they will also die off.
Plants look hungry to me yet they def have some nitro burned tips. Check your ph/tds runoff? Which nutes? The community can help better with a support ticket filled out
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-What strain, Seed bank, or bag seed (photo or auto)
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I havnt measured ph levels don’t have any device to
I’m not a novice grower also not an expert
But it is not clear to me if it is a deficiency or an excess
Deficiency/excess is only part of what you need.
Ppm/tds runoff and pH data would help decide if you’ve got a lockout issue, or a deficiency/excess issue. Adding more will not help if it’s locked out.
Hey how are you looking at ur plants i see abit of nute burn on the tips of the leaves but as far as leaf colour i dont think its a potassium or phosphorus def i believe that ur plant has a magnesium def ,in flower ur plant can get deficiencies lile magnesium and calcium and phosphorus and potassium and zinc these are some of the deficiencies u may run into i will do a bit of research to see if i can find exactly what it is and i will get back to u
Ok i just had a look at deficiencies and i believe that i may of got it down to two things it may be and both of these look very similar to each other now i believe u have either a magnesium def or a iron def now u can fix both things you can give ur plant some epsom salts mixed with molasses when u water ur plants again the epsom salts will help the magnesium and sulphur while the molasses will cover the iron , calcium and other minerals that ur plants need
Hi there and welcome to the neighborhood. If you check Amazon, the meters for ph and tds or ppm made by Apera or Bluelab are good.
Looks like a Nitrogen deficiency to me with a little bit of nutrient burn.
