No, grow lights are not necessary for indoor plants. However, they can be beneficial in some cases. For example, if you have a plant that is struggling to grow or produce flowers, using a grow light can help it to get the extra light it needs. Additionally, grow lights can be used to extend the growing season for your plants by providing them with artificial light when natural sunlight is not available. Ultimately, whether or not you use grow lights for your indoor plants is up to you and what works best for your particular situation.