brown spots/yellow leaves

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can anyone tell my mate whats wrong with his plants ?his room is 4ftby2and a half, he has a 400wt hps it has a 4"extract fan on it ,the plants are in 2gal pots ,the soil is just potting soil the soil has got some nutes in as it says on the bag to feed after 6 weeks ,the food he has is advanced hydro 1,2,3.
they are now 6 weeks old and about 2foot tall ,just put on 12/12 . everything looked ok to me up till last week , then leaves started to get brown spots on them then a few of them went yellow.
now the ones that had the spots have curled up as if they are dead but i can see the veins on the leaves are still alive , he has gave them one dose of epsom salt last week and then started to folar feed also fed them he is now lost with all the info about. i have looked it up for him and i think its a mg/zinc deff but i have never grown i just got it in a few plant abuse gides am i right or wrong ? i am not sure if anyone can help thanks

 

you got the virus man you going to have to throw the plants away

 

What virus??

Looks like nutrient problems to me.
The most common mistake is to overfeed you plants.
Flush the soil and don't feed anymore, see if the plant changes.

Growing in soil, I would never add nutrients. Change your soil if you have to, but don't add nutes. You will never get the right balance. You have to remember that the nutrients do not get used up equally, so adding nutes will create a major imbalance, unless you can actually measure the concentrations and compensate appropriately, which you can't.

Normally when growing in soil, you will transplant just before flowering, so the soil should have plenty of nutes to last the 6 to 8 weeks. In the last 2 weeks, you don't want your plants to be taking in nutes anyhow, or your bud will taste 'foody'.

The plants will do better with a lack of nutrients than they will with too much.
Too much nutients will cause nutrient lock which will usually appear as patchy discolorations and is technically a deficiency of some nutrient that is being locked out, like Mg.

Lack of nutrients will mostly just slow the growth or cause the leaves to yellow.

Improper PH can also cause nutrient lock. Make sure the ph of the soil is in the 5.5 to 6.5 range. Higher or lower will cause the certain nutirents to solidify, which is what nutrient lock is.

Sorry for the late reply. I'm sure it's probably too late, but this is a common problem and someone else will find it helpful.

Especially if you are a new grower, just dont' even consider nutes. the Soil is good enough, even if it's inadequate, it will just mean that your plants will not grow as well.
Adding nutes to soild is a sure-fire way to cause problems unless you know exactly what you are doing.

If you insist on adding nutes, use organic nutrient supplements since the organic material acts like a time-release mechanism. And flush your soil every couple of weeks to remove salt and nutrient buildup.

 

what virus are you talking about?