Your Pot Plants Don’t Need Gravel
We’ve all heard the advice to add gravel to the bottom of the plant pot, and some of us may have even done so. But gravel doesn’t improve drainage in any way, and you’re probably better off without it.
What is gravel supposed to do
Plant roots should not stay wet for too long. Some plants like “well-drained” soil, where water does not stay long. Others can tolerate more water, but if the plant is truly aquatic, it won’t want to sit in a pool of dirty soup for long.
Gravel drains better than soil because there is a lot of space between stones. So what? Your plant is not planted in gravel, but in soil. The soil will hold the same amount of moisture, whether there is gravel underneath or not.
Why you should avoid gravel
If you fill part of the plant container with gravel, you will reduce the amount of soil space. Now the roots of the plant have less room to grow.
On a plant with a drainage hole, water will saturate the soil before dripping onto the gravel and pouring out through the drainage hole. Without gravel, the soil is still saturated, but then drips straight out of the hole. Gravel adds nothing to this equation.
Without a drain hole, one might think that gravel creates a reservoir for water that collects underground. But the soil will still touch the gravel and seep between the rocks over time.
Use a coffee filter if you are worried about dirt falling out
Another purpose of gravel is to leave some space between the soil and the drainage pit. But we live in our time, and we have better technologies for this work than stones.
Cover the hole with something that allows water but not dirt to pass through. Some options:
- Coffee filter
- Piece of window partition
- Mesh fabric
The coffee filter will break over time, but by this time the dirt will settle and the likelihood of it falling to the bottom of the container will be reduced.
What to do if your pot has no drain holes
It is difficult to maintain good drainage without a hole in the bottom of the pot, so you really only have three options:
- Water very carefully . If you never over-water the plant, it doesn’t matter. Good luck.
- Create your own drainage holes . Drill or poke holes in a plastic pot with a suitable tool. For a ceramic pot, use a stone drill .
- Use two pots . An outer pot without a hole can be your family pottery. But inside, use a pot with drainage holes. It can be very cheap and lightweight plastic that costs a penny at a garden store.
If you are using two pots, you can easily remove the inner pot while watering. Or add gravel to the bottom of the outer pot if you know the dirt won’t seep in and you can inspect and empty it at any time.