Spider plants do not particularly like coffee grounds. While coffee grounds are often touted as a natural fertilizer and soil amendment, they are not the best choice for spider plants. Coffee grounds are acidic, and spider plants prefer slightly acidic soil to neutral soil pH levels (around 6.0 to 7.5). Adding coffee grounds to the soil can lower the pH too much and create an unfavorable environment for the plant. For a list of plants that do like coffee grounds visit my Which Indoor Plants Like Coffee Grounds (and how I use my Keurig to make fertilizer) post.