Reef-Friendly Landscaping Shows Promise for Maui Properties
Posted on Apr. 23, 2024 / Fertilizer , Sustainability / Subscribe
By: Jill Wirt
In late 2023, the Maui Nui Marine Resource Council (MNMRC) worked with 12 local properties to apply a biological soil amendment to high traffic or problem areas as test plots, with the hopes of not only reducing the amount of chemicals entering nearby coastal waters, but also reducing the presence of disease, pests, and other landscaping issues. The soil amendment, produced by SoilThrive Hawaii, LLC, aimed to restore soil microbiology, which supports soil and plant health to help combat pests and diseases.
At the program's start, SoilThrive visited the properties to understand the goals each site hoped to achieve by creating a test plot. The most common goals were to address pest issues such as whiteflies, reduce brown spots in lawns, and support plant growth. During this initial visit, the consultant drew soil samples to assess soil microbiology levels, which indicated the presence of chemicals, with a lack of soil microbiology (i.e. high bacteria counts) pointing to the use of chemical pest treatment or synthetic fertilizers. After these assessments, SoilThrive applied the soil amendment via foliar spray once a week for four consecutive weeks.
Throughout the rest of the program, each property was provided with soil amendment and guidance on adopting reef-friendly land care practices that would work for their area. Each test plot received six spray treatments from SoilThrive via foliar spray over the 12 weeks and ranged in size from 10,000 to 12,000 square feet with varying characteristics such as turf lawns, resort ornamentals, and farm crops.
At the end of the test period, a combined 138,000 square feet from 12 South and West Maui properties had been treated. Many showed promising results, including diminished pest and weed presence, increased plant health and appearance, and beneficial soil microbes in areas treated with the amendment. Soil samples taken at the end of the period measured fungi, bacteria, actinobacteria, fungi-to-bacteria ratio (F:B), protozoa, flagellates, amoebae, and nematodes. While this sampling method is small and may not provide a comprehensive picture of the test plot at scale, certain indicators show obvious positive results. For example, the test plot at Hale Royale dealt with grubs causing brown patches in their lawn before treatment. At the end of the program, the patch completely disappeared and healthy grass grew in its place. Similar results were seen at many of the participating properties and conditions at almost all test plots indicated that the continued application of reef-friendly practices would lead to more efficient water use and lowered maintenance and product costs over time.
Figure 1. Grass in the test area showed browning as well as a dead patch caused by grubs before treatments of the biological soil amendment. Photo Source: SoilThrive Hawaii
Figure 2. A significant improvement in the health of the grass after the 3-month test period of biological soil amendment applications. Photo Source: SoilThrive Hawaii
These early results are exciting because they demonstrate how the landscaping industry could create a positive, lasting impact on our land and reefs if more professionals begin to adapt natural products and reef-friendly practices. As a community, we know that implementing sustainable practices is critical to ensuring the preservation and longevity of our island home. It is encouraging to see that a thriving landscaping industry and a healthy environment can exist together and feed and nurture one another.
As we share the results from our pilot program, we hope to connect with more people interested in adopting natural land-care practices and driving better outcomes for both plant life and coral reefs in Maui County. We understand that the first step to making this positive change is making alternative products and the skills to use them, accessible to the public. In the summer 2024, MNMRC will host its first 10-subject Reef-Friendly Landscaping Certification Course for landscaping professionals, which will be available to the public.
For more information about reef-friendly landscaping practices or the 10-subject certification program, please email [email protected].
Jill Wirt currently serves as the program director for the Maui Nui Marine Resource Council’s Reef-Friendly Landscaping program, which helps resorts, businesses, and homeowners adopt organic land-care practices and move away from synthetic products that are harmful to Maui’s reefs and marine life. She holds a master’s degree in coastal and marine resource management from the Bren School of Environmental Science & Management–University of California, Santa Barbara. She obtained her bachelor’s degree in Environmental Sciences at San Diego State University.
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