Why Soil and Black Cinder Are Hard to Find on Hawai'i Island

The striking contrast of black cinder adds a vibrant touch to your landscape design.

If you've recently moved to Hawaiʻi Island or are starting a landscaping project, you might be surprised by the lack of soil in some areas and the difficulty in sourcing black cinder—even though lava rock is everywhere. Here's why:​

1. The Island Is Geologically Young

The Big Island is the youngest of the Hawaiian Islands, with many lava flows less than 1,500 years old. In regions like Pāhoa, soils are often shallow or even absent, as they haven't had sufficient time to develop over the fresh lava. Soil formation is a slow process, influenced by factors like rainfall and the breakdown of volcanic rock into finer particles. In drier areas, this process is even slower, leading to limited natural topsoil. CTAHRmunsell.com

2. Black Cinder Is Limited and Regulated

Black cinder, is a lightweight, porous volcanic material prized for its excellent drainage properties, making it ideal for horticulture and landscaping. However, its availability is limited due to both natural scarcity and legal restrictions.​

The 2018 eruption in the Lower East Rift Zone disrupted the primary source of black cinder, forcing the closure of key harvesting sites. This event highlighted the vulnerability of relying on a single source. Department of Land and Natural Resources ​

Recognizing the importance of black cinder to industries like floriculture and landscaping, the Hawaiʻi State Legislature passed HB 834 (Act 191) in 2021. This law allocated funds to identify new, sustainable sources of black cinder for commercial use. LegiScan ​

Due to these limitations, black cinder is often sold in smaller sizes, and larger pieces suitable for landscaping are increasingly hard to find.​

3. Legal and Cultural Considerations

It's important to note that collecting lava rocks or cinder from unauthorized areas is illegal and considered disrespectful to Native Hawaiian culture. Always source materials from licensed vendors who comply with state regulations.​

Understanding these factors can help homeowners make informed decisions when planning landscaping projects on the Big Island. While the island's volcanic nature presents unique challenges, it also offers distinctive opportunities for creative and sustainable landscaping.​

Please call Soil Plus at 808-326-9645 to see if we have black cinder in stock!