If you are using a reel mower, tall grass means a lot more work. It is not impossible to cut tall grass with a reel mower, but it is better to use these tools to mow smaller amounts more often than letting the grass get too tall.
Push reel mowers can usually cut heights between 1-3/4 and 2-1/2 inches, depending on the model you select. When operating in overgrown areas, a reel mower can get bogged down, making it difficult to push it forward.
Moreover, it can cause it to jam. Due to this, push reel mowers are best used in well-maintained yards with grass that does not measure more than four inches. Even though these mowers are not the best choice for lawns with over 4-inch tall grass, it can be done. However, the task requires a bit more time as well as patience.