Grass Growth Stages and Optimal Grazing Timing for Nutrient Capture

A Misunderstanding About Grass Growth Stages

There's a fairly significant opportunity cost when cattle aren’t managed intensively and with a vision to build healthy soil. It comes in the form of nutrients, but also in carrying capacity and soil health. These are linked in a way that some farmers aren’t aware of.

The specifics will depend on each context, but there are some good generalities we can rely on. Every situation is different, yet grasses tend to follow a three-stage growing cycle that directly affects when and how we should graze to capture the most nutrition.

The Three Stages of Grass Growth

Grasses start in the vegetative stage, where the roots are getting much of the energy and the grass grows very slowly. This might be up to only a few inches tall.

The second, or elongation, stage is when the grass takes off and grows rapidly. The leaf area increases and photosynthesis increases rapidly. As the grass gets close to the end of the elongation stage, the roots dig more deeply as well, gathering nutrients for the reproductive stage. This is when the energy goes into creating seeds.

Maximizing Palatable Nutrients in the Elongation Stage

It’s at the elongation stage that the nutrients garnered from the sun are most palatable. And it’s worth noting that this nutritional value is at its highest in the early afternoon.

For the regenerative farmer, one of the main goals with his grazing is to capture as much nutrients for his grazers as possible. Understanding the mechanism here—how photosynthesis ramps up and concentrates palatable nutrients at that specific time of day—lets us align our grazing moves with the plant’s own peak rather than missing it.

Grazing at the End of Elongation to Reset the Cycle

The second main goal is to keep the grasses in the elongation stage. By grazing them towards the end of this stage, the grasses will continue to put energy into growing, sort of resetting rather than going to the reproductive stage. This prevents energy diversion to seed production and keeps the plants focused on leaf and root growth instead.

One aspect of this that is hard for many to embrace is when they move their cattle to the next pasture and there’s so much forage still available. It rankles because they feel like they’re wasting an opportunity and resource. It’s only after they grasp the benefits of capitalizing on the growth cycle for nutrients and root health and gain a vision for the greater benefits that they are able to embrace this approach.

Grazing Intensity, Root Depth, and Recovery Timing

This is where intensive rotational grazing shines, because we move our grazers off the grass quickly. Ideally, they eat less than 50% of the stalks before we move them. If less than 50% of the height is grazed, the roots remain unaffected. In fact, they’ll keep growing. With some perennial grasses these roots can grow more than 8 feet in depth, adding incredible resilience to the pasture as well as a massively increased water carrying capacity.

If much more than 50% is grazed, the root production will either stop or the roots will die back. How often a given pasture is grazed is likewise dependent upon context. But for both the growth cycle and to let plants fully recover, the minimum rest would be about 30 days in areas with abundant rain. In an area where it’s more arid, a 90 day rest would be in order. Of course, watching the grass in given pastures with a goal to graze them before they go to seed is part of the equation as well.