yellow leafs

Nutrient and/or pH issues. But without many more details about what you may or may not be doing, this is about as good an answer as anyone could give you. Start a diary to help us help you!

If your Ph is within 6-6.3 then you need some Nitrogen. If you look at a bottle of nutrients you will see 3 numbers. Like 4-6-12. The first number is Nitrogen. Find something a decent N-P-K (those numbers I listed) and feed it once and the yellowing should go away (given that your Ph and temp/humidity are in order).

"What is the problem" cokyorgunum asks. Well cokyorgunum, we can't really give you any help at all if you don't provide details. Details like: 1. Growing medium 2. Temperature and Humidity 3. Nutrient regiment 4. Light and distance to canopy 5. Watering schedule How do you expect anyone to know the answer to your problem if you don't provide details? You should really get into the habit of providing details when you ask for help. These is the basics of problem solving, no? Not only will it help us help you, but it will help you understand your issue better. Considering you are on http://growdiaries.com, you could also upload a diary of your plant so we can more accurately gauge what your problem is. I'm sure it would also help you learn how to actually grow.