The leaves start yellowing from the bottom upwards when the plant/s need nutrients, with you only having a small container the nutrients would have been used up pretty quickly. The plastic bottle you put over the top isn't doing the plant any favours; it will create an extremely humid atmosphere which will cause many problems such as rot and mould etc. The only time you need to provide a slight humid atmosphere is when cuttings are being rooted or seeds germinated. Like it says in the replies above, you should look into buying a small sodium lamp or some fuorescents.
GTC21 Reviewed by GTC21 on . just started i just started growing about 4 weeks ago. my plant is about 7 inches tall, but my problem is that the bottom most leafs r yellowing out, is their a problem? some thing i have done to it is: its in a blue party cup, and i put a clear platic bottle around it to give it the greenhouse effect, it sits on my window sill, and i put a BI-PIN blub (50 watt) light on it about 3 inches from the platic bottle. i water it once a day. also another question is how long on average will it take before i can Rating: 5