Soaking seeds before planting allows them to germinate much quicker so you will have seedling sooner and also time to resow seeds if they don’t germinate. There are ways to do it right and if done wrong could drown the seed and it would never germinate (Gardening Know How). When soaking watermelon seeds it is good to soak them in milk as they will absorb some of it and this will nourish the seed as it sprouts (Garden Guides). When soaking peas adding part of a crushed vitamin c tablet will increase vigor and promote growth. After soaking and before planting you should coat the seeds with a legume bacterial innoculant that lets them take up nutrients better ( Ehow).