Mixing different types of grass seed is generally recommended by turfgrass professionals to create a more resilient and adaptable lawn. This practice involves combining multiple species or different cultivars of the same species to produce a robust turf. These mixtures leverage the unique strengths of various grasses, ensuring the resulting lawn can handle a wider range of environmental stresses than a single grass type could manage alone. This combination forms the basis for a healthier, denser, and more visually uniform lawn.
The Purpose of Seed Blends and Mixes
Mixing different grass varieties offers a form of biological insurance for the entire turf area. This genetic diversity ensures that if one grass species struggles with a specific environmental challenge, others in the mix can compensate, preventing widespread decline. The result is a lawn with greater resilience and durability against common stressors.
Lawns created from mixed seeds are better equipped to withstand varied stress, such as heavy foot traffic, drought, or fluctuating temperatures. If one component has deep roots that access water more efficiently, it supports the overall health of the turf when surface moisture is low. This stability leads to a consistently dense and greener appearance throughout the growing season.
The use of diverse seeds also acts as a safety net against pests and disease. A genetically uniform lawn, known as a monoculture, is highly susceptible to a single pathogen that can wipe out the entire area. By contrast, if a particular disease targets one species in a mix, the others will remain unaffected. This prevents the infection from spreading rapidly and maintains the overall aesthetic quality.
Blending seeds also helps achieve aesthetic consistency across areas with micro-climates, such as spots with full sun adjacent to partial shade. A single species may thrive in the sunny section but thin out considerably in the shade. Incorporating a shade-tolerant variety, such as a fine fescue, ensures that the lawn maintains a uniform color and density in areas where a sun-loving species, like Kentucky bluegrass, would fail.
Choosing Compatible Grass Types
The success of a mixed lawn depends on choosing grasses that work together rather than compete. The most important criterion is matching the growth habits and maintenance requirements of the chosen species. Grasses should have similar needs regarding mowing height, fertilization, and water requirements to prevent one type from dominating the others.
The fundamental rule of mixing involves matching grasses within their proper climate zone. Turfgrasses are categorized as either cool-season or warm-season types, each having different optimal growing temperatures. Cool-season grasses (fescue, ryegrass, and bluegrass) flourish when air temperatures are between 60 and 75 degrees Fahrenheit. Warm-season grasses (Bermuda or Zoysia) perform best in temperatures between 80 and 95 degrees Fahrenheit.
Mixing warm-season and cool-season grasses is generally discouraged for a permanent lawn due to their conflicting active growth periods. While this may be done intentionally for seasonal overseeding to provide winter color, it typically results in a patchy, non-uniform look in residential settings. For a consistent lawn, it is best to mix different species within the same temperature category, such as combining Tall Fescue with Kentucky Bluegrass for a cool-season turf.
It is also necessary to match the chosen mix to the specific site conditions. For example, a blend designed for a sun-drenched lawn should feature species known for high light tolerance and heat resistance. Conversely, if the turf area includes significant shade, a mix that incorporates fine fescues, which are known to tolerate low light conditions, should be used to ensure even coverage across the entire space.
Practical Application: Mixing Ratios and Preparation
Successfully applying a custom seed mix requires careful attention to both the ratio of the components and the method of application. When determining ratios, it is important to understand that seed size and weight vary dramatically between species. For instance, a pound of Kentucky bluegrass seed contains significantly more individual seeds than a pound of Tall Fescue seed.
The ratios should be determined by weight, with the dominant species making up the bulk of the mix, typically between 60 to 80 percent. Secondary species are added in smaller percentages to address specific weaknesses, such as adding perennial ryegrass for its rapid germination rate. Using a weight-based calculation ensures the correct proportion of plants will grow in the final lawn.
Before loading the seed into a spreader, all components must be thoroughly mixed in a separate container, such as a large bucket or wheelbarrow. This pre-mixing prevents the smaller, heavier seeds from settling to the bottom of the spreader hopper, which would lead to an uneven application pattern. The goal is to create a homogenous blend so that every pass of the spreader distributes a uniform combination of all the desired grass types.
The process of mixing seeds must be paired with proper soil preparation for successful establishment. This preparation includes conducting a soil test to determine the pH level and nutrient deficiencies. This is followed by tilling the top few inches of soil to relieve compaction and ensure good seed-to-soil contact. Applying a starter fertilizer that is high in phosphorus will provide the necessary nutrients to support the vigorous root growth of the newly germinating seeds.