Geomagnetic field (GMF) protects living organisms on the Earth from the radiation coming from space along with other environmental factors during evolution, and it has affected the growth and development of plants. Many researchers have always been interested in investigating these effects in different aspects. In this chapter, we focus on the methods of using different types of magnetic fields (MFs) to investigate the dimensions of their biological effects on plants. The aim is to increase seed germination, growth characters, and yield of plants using the following methods: (1) Using MFs lower than GMF to study effects of GMF on the growth and yield of plants. (2) Using reversed magnetic fields (RMFs) lower than GMF to study its effects on the growth and development of plants during evolution. (3) Using static magnetic fields (SMFs) higher than GMF and reversed SMFs to study effects of the south (S) and north (N) magnetic pole on plants. (4) Using electromagnetic fields (EMFs) to increase and accelerate seed germination, growth, and yield of plants, and establish the status of plants against other environmental stresses. (5) Using magnetized water (MW) to improve plant seed germination, growth, and yield. (6) Using high gradient magnetic field (HGMF) to study magneto-tropism in plants. In this chapter, we recommend application of various types of MFs to study their biological effects on plants to improve crop production.