Limiting factors are things that limit how much or how quickly something can happen. For example, let's say you want to grow a garden. The sunshine, water, soil, and air are all important for your plants to grow and thrive, so you can think of them as potential limiting factors for your garden. If there isn't enough sun, water, or soil, or if the air is too polluted, your plants might not grow very well. So those are the things that are preventing or limiting the growth of your garden.