plant question

So, what am I doing wrong here?  My little baby chards keep flattening out and then succumbing to the void, and my wee lettuces have totally disappeared from the middle of their container.  The only thing still looking robust are my two pea plants.  They're all inside, they get afternoon light (best I can do), I water every other day or every two days, as the soil seems dry.  Tips from the experts?

go pea, go.