When a lawn “goes to seed,” the turfgrass is undergoing a natural reproductive process. This event, known as bolting or flowering, involves the grass plant producing visible seed heads on elongated stems. While homeowners desire a lush, uniform lawn of leaf blades, seed head production confirms the grass is fulfilling its reproductive cycle. Understanding the timing and implications of this process is necessary for maintaining a healthy lawn.
Understanding the Seeding Process
Grass produces seed heads in response to specific environmental signals that trigger its reproductive phase. This shift is primarily governed by photoperiodism, the plant’s sensitivity to the length of daylight hours, often combined with temperature fluctuations. For example, Kentucky Bluegrass may require 13 hours or more of daylight and moderately cool temperatures (65°F to 75°F) to initiate flowering.
The production of a seed head requires significant energy, diverting carbohydrates away from vegetative growth. The plant slows down its production of new leaf blades to focus on the reproductive structure. This results in the lawn temporarily looking thinner, uneven, or tougher to mow. A common trigger for this reproductive effort is a mild stressor, such as low mowing height, drought conditions, or a lack of available nitrogen.
Seasonal Timing for Turfgrass Varieties
The calendar timing for when a lawn goes to seed depends heavily on whether the turf is a cool-season or warm-season variety. Cool-season grasses, like Kentucky Bluegrass, Tall Fescue, and Perennial Ryegrass, are the most noticeable seed producers. These grasses typically bolt during the late spring or early summer, around May or June, as the days lengthen and before the intense heat of mid-summer arrives.
This spring seeding period is an adaptation to reproduce before the summer stress causes the grass to go dormant. The visible seed heads often appear quickly and uniformly across the lawn during this window.
Warm-season grasses, including Bermuda, Zoysia, and St. Augustine, have a less dramatic and more sporadic seeding schedule. Their primary growth occurs during the peak heat of summer when temperatures are consistently between 75°F and 90°F.
Warm-season varieties may produce seed heads intermittently throughout the summer. However, the structures are often shorter and less apparent than those of cool-season grasses.
Lawn Maintenance When Grass Goes to Seed
Adjusting maintenance practices during this seeding phase helps the grass return its energy to leaf production and maintain a better appearance. Mowing with a sharp blade is important, as dull blades will tear the tougher seed stems instead of cleanly cutting them, leading to a ragged, brown appearance and potential disease entry points.
The mowing height should be maintained at the high end of the recommended range for the grass type, adhering to the one-third rule, which dictates removing no more than one-third of the blade length per mow. Mowing too low, or scalping the lawn, can intensify the stress that encourages the plant to produce more seed heads.
Watering practices may also need a temporary adjustment, especially if the seeding was triggered by drought stress. While it is not recommended to overwater, ensuring the lawn receives sufficient, deep watering encourages the plant to focus on root and leaf growth rather than reproduction. Deep, less frequent watering is better than shallow watering, as it promotes deep root development.
Fertilization should be managed carefully, as high nitrogen levels applied during this time can promote excessive stem growth instead of delaying seed head formation. Instead of increasing nitrogen, homeowners should ensure the plant has balanced nutrients and understand that the seeding phase is temporary. Once the environmental triggers subside, the grass will naturally transition back to its vegetative growth cycle.