Do bigger seeds sprout faster than smaller ones? You sort kidney beans by weight into three groups. Small beans weigh 0.4 grams. Medium weigh 0.5 grams. Large weigh 0.6 grams. Each group of twenty beans goes into a damp paper towel roll placed in a cup of water. You open the rolls each day for five days and count how many seeds have sprouted. The large beans germinate slightly faster. By the end, 90 percent of large beans sprouted compared to 88 percent of medium and 86 percent of small.