Fundamentally, plants need three things to grow: water, sun, and nutrient-rich soil. When any of these are lacking, plants will suffer. Water without the sun will not produce the photosynthesis needed to grow. Sun without water will scorch any plant. Without the proper soil, plants may sprout, but will lack nutrients and soon die out. When all three of these are present, plants can blossom and flourish.
Spiritually, we need two things to grow: reading the Bible and praying every day. If either of these are lacking, we will suffer. Reading your Bible without praying will fill your head with facts, but you will fail to grow. Praying without the nutrient-rich content of the Bible and you will wilt. When both of these are present, you will blossom and flourish.