Jonathan Jackson/Alamy
JazmÃn Abraham-Juárez
University of Cambridge, UK
Yes, there is a difference and it comes down to how grass responds to seasonal conditions – something all plants do by dynamically adjusting to their environment.
Grasses are highly adaptable to weather fluctuations and adjust how they use energy throughout the year.
In colder conditions, grass diverts much of its photosynthetic energy to roots and storage tissues, slowing leaf growth. As temperatures rise in spring and summer, the plant produces enough energy to support rapid growth above and below ground. These shifts change growth rate and influence the chemical makeup of grass tissue.
Seasonal changes in soil microorganisms also affect grass composition. Most nutrients reach plants only after microbes convert organic compounds in the soil into usable ionic forms. Microbial activity increases in warmer conditions and slows in winter, altering the amount of nutrients grass can absorb.
Nitrogen and sulphur show the greatest seasonal variation in grass tissue, while phosphorus, potassium, calcium, magnesium and iron also tend to rise in their concentration during rapid plant growth, but to a lesser extent.
Because mowing is frequent in warm weather and during rainy seasons, the plant stays in a more constant growth cycle, repeatedly producing young tissue with higher compositions of these nutrients.
Grass also alters its production of secondary compounds that help it survive stress. For example, anthocyanins (pigments that can give leaves a purple tint) are more abundant during cold or drought conditions.
Overall, grass composition reflects environmental conditions and plant metabolism. This understanding helps guide grassland management. For example, applying nitrogen fertiliser in late autumn can support overwintering plants and promote early spring growth by making these nutrients more available to the plant.
Caroline Lehmann
University of Edinburgh, UK
In all grasslands, different plants grow and flower at different times. So cutting at different times of the year does have an impact on species and their flowering. It is why there has become a substantial no-mow movement. For example, in my highlands garden, which is an unimproved grassland, if I mow after winter and then regularly, it would prohibit the flowering of the orchids, Calamine, cow-slips, primroses and a multitude of other species. They are not only beautiful, but important for insects, and, therefore, it would also reduce the food resources for the wonderful migratory birds that visit my garden each year, such as swifts, swallows, martins and flycatchers.
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