Growing a healthy, lush lawn in Hawaii is challenging due to the year-round growing season, high humidity, and variable volcanic soil. Standard mainland lawn care practices rarely apply, as grass never goes dormant and tropical conditions encourage rapid growth and specialized pests. Successfully cultivating turfgrass requires a tailored approach, starting with selecting appropriate warm-season varieties and focusing on high-frequency maintenance.
Selecting the Right Grass Varieties for Hawaii
The tropical climate dictates the selection of warm-season grasses, as cool-season species like Fescue or Kentucky Bluegrass cannot survive the sustained heat and humidity.
Bermudagrass is a popular choice for high-traffic areas and yards receiving full sun due to its vigorous, dense growth and excellent wear tolerance. This turfgrass establishes quickly through stolons and rhizomes, allowing rapid recovery from damage, but it requires high maintenance, including frequent, low mowing.
Zoysiagrass offers a balance between durability and lower maintenance, possessing better shade and drought tolerance than Bermudagrass once established. It forms a dense turf that naturally resists weeds, making it a favorite for residential lawns. However, its slow establishment rate means it is often installed using sod or plugs.
The third viable option is St. Augustinegrass, which is the most shade-tolerant warm-season grass and is identifiable by its coarse, wide-bladed texture. While it thrives in partial shade, St. Augustinegrass is susceptible to thatch buildup and certain insect pests, which must be factored into its long-term care plan.
Soil Preparation and Establishment Methods
Lawn success begins beneath the surface, especially in Hawaii, where soils often consist of nutrient-poor, weathered volcanic ash or lava rock derivatives. Initial soil testing is recommended to determine the existing pH level, which can range from acidic in high-rainfall areas to alkaline near the coast. Turfgrass generally prefers a slightly acidic to neutral pH of 6.0 to 7.0, and amendments like lime are used to raise the pH in overly acidic soils.
Preparation involves tilling the soil to a depth of at least four inches to improve aeration and water movement. Incorporating organic matter, such as compost, enhances nutrient retention and helps regulate soil moisture. Proper grading is also necessary before establishment to ensure surface water drains away from structures and prevents pooling, which can lead to disease.
Establishment Methods
The quickest way to establish a new lawn is by laying sod, which provides immediate, dense turf and minimizes weed intrusion, though it is the most costly method. Sprigging involves planting grass runners that contain nodes and is an economical option for Bermudagrass and Zoysiagrass, though it requires more time for full coverage. Seeding is the least common method for these warm-season varieties, as many popular cultivars are hybrids with poor seed germination rates, making plugs, sprigs, or sod the typical choice.
Essential Long-Term Care and Maintenance
The year-round growing cycle in Hawaii demands a consistent, high-frequency maintenance schedule. Warm-season grasses grow rapidly in the tropical heat, often necessitating mowing every five to seven days during peak periods to maintain turf health. Following the one-third rule—removing no more than one-third of the grass blade per mowing—is important to prevent stressing the turf.
Specific mowing heights are recommended for different species. Bermudagrass should be kept short at 0.5 to 1.5 inches for a manicured appearance. St. Augustinegrass should be maintained at a taller height of 2 to 3 inches for improved shade tolerance and moisture retention.
Fertilization must be a continuous, year-round practice focusing on high-nitrogen formulations to support constant growth. High-demand grasses like Bermudagrass may require a monthly feeding of approximately one pound of nitrogen per 1,000 square feet. Other varieties can be sustained with a granular application every six to eight weeks. Applying controlled-release nitrogen sources helps prevent excessive growth flushes and reduces the risk of fungal diseases associated with high nitrogen levels.
Watering practices should prioritize deep and infrequent irrigation to encourage the development of strong, deep root systems. Established lawns benefit from receiving three-quarters to one inch of water per application, typically two to three times per week in the summer. Watering in the early morning is advised to ensure the grass blades dry completely before nightfall, minimizing leaf wetness and reducing the likelihood of fungal pathogen development.
Managing Tropical Pests and Diseases
The warm, humid conditions provide an ideal environment for various turfgrass pests and fungal diseases, requiring attentive monitoring for early intervention.
Common Pests
Chinch bugs are a major pest, especially for St. Augustinegrass. They congregate at the base of the plant to suck plant juices, causing irregular yellow and brown patches. Infestations are often first noticed along sidewalks and in the hottest, driest areas of the lawn.
Mole crickets damage turf by tunneling through the soil and feeding on grass roots and shoots; their activity is noticeable at night. Monitoring can be accomplished using a soap-flush test, which brings the crickets to the surface. Control often involves targeted granular baits.
Armyworms and sod webworms are prevalent caterpillars that feed on grass blades, sometimes causing widespread damage. They can be managed with treatments containing entomopathogenic nematodes or an appropriate insecticide.
Fungal Diseases
Fungal diseases thrive in prolonged periods of leaf wetness and high temperatures. Brown patch, caused by the fungus Rhizoctonia solani, appears as circular patches of sunken, brownish-yellow grass. It is often exacerbated by over-fertilization with soluble nitrogen or by watering late in the day.
Dollar spot manifests as small, bleached patches of turf. Its severity increases when the turf is underfed or when moisture persists on the leaves for extended periods. Cultural controls, such as correcting fertilization and watering practices, are the first line of defense against these diseases. Systemic or contact fungicides are used for severe outbreaks.