A lot of tips for caring for ornamental plants are in vogue, one of which is to put a layer of gravel on the bottom of the pot. However, this is not really necessary.
Adding a layer of gravel, rocks, or pot pieces to the bottom of the pot is a common practice for most ornamental plant enthusiasts.
However, a scientific article published by the University of Illinois, USA, claims that a layer of gravel at the bottom of the pot improves drainage – this is a myth. Instead, the water immediately flows over the gravel, the water will or will pool on the ground directly above the gravel.
Water is collected until there is no air space left. Once all available air spaces in the soil are filled, excess water drains into the gravel below.
Thus, the gravel below it does little to keep the soil above it from becoming saturated with excess water.
Does gravel help plant drainage?
If you’re not sure if gravel helps drainage, the answer is no. Soil scientist Kevin Hendreck, author of Gardening Downstairs and A Good Garden with Less Water, says the practice increases the risk of damage to plants from overwatering.
In fact, putting a layer of gravel on the bottom of the pot will damage the plant.
Does a layer of gravel improve air circulation in the pot?
Plants need good drainage so that their roots can get enough oxygen. Water passes through rough-textured materials faster than through fine-textured materials.
However, water cannot easily move from the fine textured material layer to the coarse textured material layer. This means that the water, instead of flowing freely and smoothly, is between the soil and the drainage layer and does not begin to flow down until the soil is completely saturated.
There should be no land to put pebbles under the plant pots.
There are several reasons why you shouldn’t put pebbles in the bottom of flower pots, including the following.
The BBC says it’s wrong to put pebbles under plant pots. It is better to pour a layer of sand underground, which will allow water to penetrate into it, and then, if necessary, be absorbed by the roots.
Adding gravel for drainage reduces the amount of soil available to plant roots. Essentially, this means that you are narrowing the pot and these conditions are unfavorable for the plant. University of California gardener Sue McDavid says the plants love good drainage, especially in pots. If water stagnates around plant roots for an extended period of time, root rot will damage and possibly kill the plant.
Instead of running water straight through the soil, over gravel or other material, and through drainage holes, the water completely saturates the soil so there is no air space left. This can take a long time and temporarily the plant roots will be deprived of oxygen.
A layer of gravel or pot bedding at the bottom of the container adds unnecessary weight because it is heavier than most light clay soils and difficult to move.