This is a topic with mixed opinions...
Putting rocks at the bottom of a planter is a common habit of many gardeners, especially those who do a lot of container gardening.
It is thought that the rocks add drainage - the water pools down in amongst the rocks to prevent soggy soil and potential root rot.
If your planter already has adequate drainage and you're using a good quality potting mix, you might not need rocks. For a horticulturist's expert take on the subject, click here.
Pros:
Cons:
Alternatives:
It is thought that the rocks add drainage - the water pools down in amongst the rocks to prevent soggy soil and potential root rot.
If your planter already has adequate drainage and you're using a good quality potting mix, you might not need rocks. For a horticulturist's expert take on the subject, click here.
Pros:
- Improved Drainage: Rocks can help prevent soil from clogging drainage holes and allow excess water to escape more freely.
- Prevents Soil Loss: They can act as a barrier to keep soil from washing out of the drainage holes.
Cons:
- Drainage Myth: Some studies suggest that adding rocks doesn’t significantly improve drainage. Instead, it can create a perched water table where water sits above the rocks and doesn’t drain properly.
- Reduced Soil Volume: Using rocks reduces the amount of soil available to plant roots, which could potentially limit growth if the planter is small.
Alternatives:
- Landscape Fabric or Mesh: Use a piece of landscape fabric or mesh over the drainage hole to keep soil in place while still allowing for proper drainage.
- Proper Soil Mix: Use a well-draining potting mix designed for container plants, which can be more effective for managing moisture.
Expert tip: placing small rocks on top of your potting mix may prevent fungus gnats from breeding there.