little yellow spots, pale brown scabbing

[blueleaf]

hello fellow growers !
its my first grow, outdour, growing from seed
im about 5th week
i have this problem - little yellow spots and brown scabbings
there are three plants and one of them is clean
so i guess its not the soil or water etc...
im not using any fertilizers yet...
any tips or help would be much appreciated
some photos ( sorry about q. its from my cellphone)
P.S. the plants are not planted or near soil
my guess - the original soil was contaminated...
so if its a pest problem how can i sterilize the ground ?
for my understanding heating will sterilize but also
make the ground of lower quality. 10xINadvance
http://img46.invalid.com/img46/7941/31052009315.jpg
http://img190.invalid.com/img190/476/31052009316.jpg

 

[Dr Herbal]

bugs mate that my guess eather thrips or spider mites id get some spay mate :)

 

[blueleaf]

okay, they are too small to see, and holes have black dots near it,
how should i strelize the soil next time ?

 

[KingCrimson]

spinosad?

 

[Dr Herbal]

Ya got spider mites mate them little dots are its shit lol......ya got a mag glass you should see them underside of the leaves if you still carnt see out u mite of cought it early id go for friendly bug but iam indoor only dont know if its worth it hopfully some can help on that if not bug spray should help
peace bro

 

[sour power]

if its spider mites go buy some neem oil or bang

 

[blueleaf]

thanx a lot guys... i think ill try some neem oil and let you know if it worked.
is there a way of sterilizing ground with chemiclas or neem oil ?