I have noticed small holes in the leaves of one of my youngest plants. I'm growing in a glass greenhouse , and in soil. I changed the light balance a bit so the holes are more noticable. There seem to be no insects on or under the leaves. The holes appeared in a matter of two or three days.
I'm thinking about using this. http://www.amazon.com/gp/product/B0054YQ1WI/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A3VZKFNMHAPZBO
Any suggestion about anything else