Re-potting Plants: A Guide on Lava, Soil, and Your Green Thumbs
In the world of container gardening and plant care, lava rocks play a significant role in maintaining healthy root environments. Here's a guide on how to select, use, and prepare these versatile rocks for optimal plant growth.
Choosing the Right Lava Rocks
When it comes to lava rocks for plant drainage and aeration, the key is to choose porous, lightweight stones that create air pockets and improve water flow through the soil. For container gardening or repotting, select lava rocks that are small enough to provide adequate space for roots to grow and ensure proper drainage. Rounded or irregularly shaped rocks are preferable as they help prevent damage to plant roots [1][2][3][5].
Best Practices for Using Lava Rocks
Lava rocks function best when mixed with organic potting mix or soil amendments to balance moisture retention and aeration, rather than being used as the sole medium [4]. Incorporating lava rocks into the potting soil helps prevent soil compaction, improving soil structure and facilitating root respiration and water percolation [5].
Preparing Lava Rocks
Before use, lava rocks should be rinsed under running water to remove dust, dirt, or debris. They can be sterilised by boiling or soaking in a mild bleach solution to ensure cleanliness [6].
Repotting Plants
Knowing when to repot plants is essential for their continued health. Signs of needing repotting include stems and foliage more than three times the height of the pot, roots visible, water pooling on the soil, the plant drying out faster than usual, the soil dry and crumbling, growth has slowed, a build-up of salt and minerals, yellowing leaves, and loss of leaves. As a general rule, plants need fresh potting soil or a new container every 12 to 18 months [7]. Spring, before the start of the growth season, is usually the best time to repot plants.
Planting with Lava Rocks
When adding a plant to the pot, dead or extra-long roots should be removed, and the plant should be centred before adding potting mix around it. When layering lava rocks in a planter, a layer of rocks should take up about 5-10% of the planter's inside space [8].
Purchasing Lava Rocks
For quality and authenticity, it's recommended to purchase lava rocks from reputable suppliers [9]. When selecting lava rocks, opt for those that have been naturally weathered or tumbled to avoid sharp edges or protrusions. Sharp edges can damage plant roots and also pose a risk of injury during handling.
Fertilising and Maintenance
Fertilising should be avoided for about a month after repotting a plant to allow the roots to adjust to their new environment [10]. Regular watering, especially after being added to the pot, with extra water due to its adjustment to its new home, is crucial for plant health [11].
In summary, lava rocks should be porous, appropriately sized, and used to complement potting soil, ensuring good aeration and drainage when repotting plants. This helps maintain healthy root environments and prevents typical problems like waterlogging and poor oxygenation [2][3][5].
When repotting plants, it's essential to choose small, lightweight, porous lava rocks that create air pockets and improve water flow, suitable for container gardening or repotting. To enhance soil structure and facilitate root respiration, lava rocks should be mixed with organic potting mix or soil amendments [1][7].
After purchasing lava rocks from reputable suppliers, they need to be rinsed under running water to remove dust and debris, then sterilized by boiling or soaking in a mild bleach solution for cleanliness [6][9].
