Spring is the best time to start feeding your plants as the ground is still holding onto the moisture from the spring thaw and from spring showers. This is important because the fertilizer will sink into the soil easily and this will create an excellent condition for your plants to start growing. There are an abundance of plant food and additives to promote healthy roots and give your plants the optimal beginning. Many plants benefit from feeding throughout the season as well. You need to check on the fertilizer package for instructions on application and frequency.