Wondering Why You Should Not Add Gravels to Pots? Here’s us busting an old myth of the most common practice gardeners follow.
Every time you prepare a pot for planting, you add a layer of gravel in the bottom for drainage! But is it essential or not required at all? Why You Should Not Add Gravels to Pots? Or should you? Let’s find out!
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Should You Add Gravels to Pots?
Adding a layer of gravel, stones, or pot shards to the bottom of the container is a common practice that most gardeners (old or new or even experts) do. But do you really need to do this? We say NO!
To support our claim, we refer to this educative article on Illinois University, which states –
It is a myth that a layer of gravel (inside the bottom of an individual pot) beneath the soil improves container drainage. Instead of extra water draining immediately into the gravel, the water ‘perches’ or gathers in the soil just above the gravel.
The water gathers until no air space is left. Once all the available soil air space fills up, the excess water drains into the gravel below. So gravel in the bottom does little to keep soil above it from being saturated by overwatering.
Does Gravel Help With Drainage?
If you are confused if gravel help with drainage, then the answer is No. Soil scientist Kevin Handreck, the author of Gardening DownUnder and Good Gardens with Less Water, states that crocking increases the risk of damaging your plants by overwatering. In fact, adding a layer of gravel at the bottom of the pot will impair it.
Associate Professor Linda Chalker-Scott, an urban horticulturist at Washington State University, calls it a myth that refuses to die. She says regardless of solid scientific evidence to the contrary in her report! Nearly every book or website on container gardening recommends placing coarse material at the bottom of containers for drainage.
Does a Layer of Gravel Improve Air Circulation?
We know that plants need good drainage so that their roots can receive adequate oxygen, and we also know that water passes through a coarsely textured material faster than it does in fine material.
What we miss here is that water does not move easily from layers of finer textured materials to layers of more coarse-textured materials, which means instead of passing freely and easily, the water sits between the soil and drainage layer and doesn’t start to drop until the soil is saturated completely. ABC SCIENCE also tried to debunk this myth in its article; click here!
Why You Should Not Add Gravels to Pots?
1. It Worsens the Drainage
In our practice, we didn’t find any help from adding a bottom layer of coarse material in containers. BBC too states that this is not true, and it’s better to have a layer of sand underneath soil that will allow water to drain into it and later be sucked up by roots if needed.
2. It Takes Additional Space
Adding gravel for drainage reduces the volume of soil available to plant roots. Basically, it means you make a pot even smaller in size and, as a result, get an unhappy crowded plant.
The article by James D. Kramer also supports the claim. You can check out his interesting article here!
3. It Causes Root Rot
University of California’s Master Gardener, Sue McDavid states that plants like good drainage, especially those in containers. If water pools around plant roots for long, root rot will damage and possibly kill the plant.
Instead of water draining immediately through the soil, then into gravel or other material, and out of the drainage holes, water will completely saturate the soil so that no air spaces are left. This could take a long time, and in the interim, plant roots will be starved for oxygen.
4. Gravel Adds Unnecessary Weight
A layer of gravel or pot shards at the bottom of a container adds unnecessary weight because it is heavier than most lightweight potting soils and becomes hard to move.
So, What Should You Do?
Actually, nothing. Keep the pot as it is. If you fear the soil getting washed out, you can prevent this by placing a layer of paper towel or newspaper over the holes before adding the growing medium.
Also, ensure that you never grow plants in a pot without drainage holes.
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The Bottom Line
Adding gravel at the bottom of the container can severely hamper the drainage, which can waterlog the roots and prevent proper airflow. This will result in the growing medium attracting soil-borne diseases and root rot that may cause the death of a plant.