Jiffy plugs are not the same as Jiffy pots. The peat pots, in my experience, seriously interfere with root growth, the plugs do not. Contrary to marketing claims, I found that the peat pots do not break down quickly enough to allow free penetration of roots when the entire pot is planted in the final soil or pot. I still use the plugs because they are easily available locally, and work well to get seedlings started and duds identified before final planting. I will never use the peat pots again, they are a waste of money and do not allow normal root development, at least not quickly enough for our favorite plant.