first grow? stupid question but i need help.

okay so right now im growing my first plant out of a red cup that youd drink beer out of at parties. its about 5 or 6 inches tall but ive had it for about 10 weeks or 9? is that the right size? also the leaves are yellow at the bottom and then green then yellow at the top. is this normal? how do i fix it? ill post a picture

Looks to me like you need to repot asap. Or add more soil to the cup and give it a good drench of plain water. The yellowing is likely that the plant has used up all the available N nitrogen in the soil. Repot in a larger pot and water she will thank you. 1BMM

Yes - repot that poor baby ASAP if you don't want to lose it! It is likely starving for nutes from the small amount of soil it has probably stripped clean of them. It should be much bigger at 9 or 10 weeks. I'm a new grower and using only CFLs, but my plants range from 8-16 inches now and they are just 51 days old. I will be switching them to flower in a few days when they reach 8 weeks. If you catch it quick, you should be able to save your plant and see some progress as soon as it gets over the shock. It may even be so happy to have fresh soil and nutes, that it will take right off in a couple days. The yellowing of the leaves is probably because it is feeding off them as a last resort. When you re-plant her, bury the stem in soil further - up to about an inch below the first leaves. This will help stability and allow room for further root growth from the stem area that you cover. Good luck and let us know if you save it.