It’s a mess.
You love your plants but there’s potting soil all over the floor.
Is there some way to cover the drainage holes, so the soil does not fall out?
The best way to cover drainage holes in pots is to use a material that will drain excess water but prevent the soil from falling out. This could be materials such as terracotta pieces, newspaper, dried leaves, coco coir, or landscape fabric.
I’ll help you with 6 proven tips you can use to cover the drainage holes in your pots and never face the problem of messed up floors indoors or outdoors.
Let’s take a look.
6 tips for covering drainage holes in pots
You can use organic or inorganic methods to cover the drainage holes, and they each have their benefits and drawbacks.
1. Use a pot with small drainage holes
If you are at the stage when you need to buy a pot, then pick one that has many small drainage holes. This way, you won’t need to worry about covering the drainage holes.
You won’t have the issues such as too much potting soil leaching out from the drainage holes.
If you have already picked the pots and they have one or more large drainage holes, then it’s best to cover them up using the methods below.
2. Cover the drainage holes with organic liners
You can cover the drainage holes with organic materials that are listed below. The benefit of using these organic materials is they degrade over time and enrich the potting soil.
But this is also a drawback because it means the cover will go away and the potting soil may leach out from the drainage holes.
Coco coir is the fiber extracted from the coconut and works well as a liner in the pot to cover the drainage holes.
Sphagnum moss has a similar texture to coco coir and works well as a liner. It retains moisture while draining out excess. I prefer coco coir because it’s cheaper and sustainable compared to sphagnum moss.
Burlap is an inexpensive fabric material you can use to line your pot and cover up the drainage holes. It works well to retain moisture and drain the water but prevent soil from leaching out.
I’ve often used folded layers of newspaper as a liner in the pot when I did not have any other material available when transplanting seedlings in the pot.
Many people will have coffee filters at home and you can use those as the liner to cover up the drainage holes. The coffee grounds can give a boost of nutrients to the potting soil. Or you can add those to your compost bin.
Dried leaves are another option that I often use to line my potted plants. I can get many of these leaves from the trees and plants growing near the house and use those. Just be careful those leaves don’t have any pests or diseases.
Straw or hay could be something easy to get if you have access to a farm. It works well as a liner for the potting soil.
Toilet/Kitchen paper rolls
Toilet or kitchen paper rolls are also something you already have at home and can recycle as part of the liner on the base of your plant pot. They work well to allow moisture to drain but prevent leaching of the potting soil.
Milk or egg cartons can work really well as a liner before you add the potting soil to the pot. Just make sure that you either cut them up into pieces or pierce some holes in them so the excess water can drain out of them.
3. Cover the drainage holes with inorganic liners
You can use inorganic materials that are mentioned below to cover up the drainage holes in the pot. The benefit is these materials will last a long time.
The drawback is that some of these materials may mix up with the potting soil and you may not be able to reuse the potting soil after a while.
Plastic window screening
One of the best options is to use a plastic window screening to cover the drainage holes. This is a long-lasting alternative that works well to drain the excess water but protect the potting soil.
I’m sure most people will stumble upon packing peanuts when they receive some deliveries at home. These can be a good option to cover the drainage holes.
The problem is that the packing peanuts can mix in with the potting soil over time and make it unsuitable for reuse. You can avoid this problem by covering the packing peanuts with a plastic mesh.
Make sure the packing peanuts are made from non-organic material, otherwise they will degrade into the potting soil and clog it up.
Landscape fabric is a cheap option that you may already have lying around with your gardening equipment. Place a layer of this material on the drainage holes to prevent soil from leaching.
If you have some broken terracotta pots, you can reuse the material as an inorganic liner for your plant pots. Break it into uneven chunks that you can place inside the pot as a drainage hole cover.
Crushed soda cans
Crushed soda cans work well to cover the drainage holes, but leave enough space for aeration and the excess water to drain out from the drainage holes.
I would still suggest adding a plastic mesh or window screening on top of the layer of crushed soda cans to prevent the soil from settling in the crevices between the cans.
Plastic milk jugs
Plastic milk jugs are a cheap option, as you can reuse the jugs to cover the drainage holes. This will work only for large pots that hold a lot of potting soil and have sufficient space for a layer of the plastic jugs.
Similar to the crushed soda cans, you can add the plastic mesh or screening on top of the jugs to keep most of the soil on top of the layer of jugs.
4. Use a pot with a saucer under it
You can place the pot on a saucer that is larger than the pot. This will prevent the potting soil from leaching out from the drainage holes when you water it.
The problem is you can’t leave the saucer containing water that has drained out. This will get absorbed back into the potting soil, causing overwatering problems.
So you need to empty the water from the saucer after you have watered the plant. If some potting soil has leached into the saucer, you can put it back into the pot.
I asked gardeners what method they used to line their pots and prevent soil from falling out. Below are the results of the survey. 22% used coffee filters in their pots. Surprisingly, 22% did not use any liner and were OK with a little soil being lost. 8% added small rocks which we know can cause drainage problems.
5. Place the plant pot inside another larger pot
The idea is to place the plant pot that has the drainage holes inside another larger pot that does not have the drainage holes.
Now you can water the plant pot and the excess water will drain out and collect inside the larger pot. You will need to throw away this water after the watering.
If the water remains in the larger pot for a long time, the potting soil will absorb the water back from the drainage holes and face overwatering problems.
Another option is to take the plant pot out of the larger pot before watering. Then do the watering under the kitchen sink or bathtub. Once the excess water has drained out, you can place the plant pot back inside the larger pot.
6. Do not use gravel to line the plant pot
It might seem logical to use gravel as an inorganic liner in the plant pot and cover the drainage holes. But this prevents the water from draining well and causes overwatering issues.
The problem with using gravel or small stones is that they cover up the base of the potting soil and make it harder for the water to move from the potting soil to the drainage holes.
You want material that is larger and uneven, such as some of the materials above, e.g. terracotta pieces, packing peanuts, crushed soda cans. These materials have plenty of air space to ensure the water flows through and reaches the drainage holes. But prevent the potting soil from leaching out.
Why you need to be careful covering drainage holes?
It’s useful to cover the drainage holes as it prevents a waste of the precious potting soil you added. However, you need to be careful and avoid a situation where the drainage holes are blocked either intentionally or unintentionally.
This may happen unintentionally when the potting soil or the liner itself is clogging up the drainage holes. Or it may happen intentionally because you either don’t have drainage holes in the pot or have covered them up with plugs.
The main issue you’ll face with incorrectly covering the drainage holes is overwatering, where excess moisture remains in the potting soil.
1. Root rot
The major problem of overwatering will be root rot because the plant roots remain in moist conditions for a long time. This invites fungal diseases to the roots, causing them to rot, turn black, and smell. If left untreated, all the roots will eventually die and so will the plant.
The symptoms of overwatering will involve yellowing leaves and stunted growth. These symptoms are like underwatering. So the best way is to dig the potting soil a little and inspect the roots. You’ll also find the potting soil is always moist and does not seem to dry out.
2. Salt deposits
You may be using tap water for the potted plants and this may be hard water that contains a lot of salts and minerals. Even if the water does not contain much salts, they may collect in the potting soil from the fertilizers that you add.
If the drainage holes are blocked, these salts and minerals cannot leach out of the potting soil and will remain there.
The problem with too much salt in the potting soil is it will dehydrate the plants as they cannot absorb the required moisture from the soil.
You’ll find that the leaves are yellowing and the plant is not growing well. You may see white salt deposits on the surface of the potting soil.
The potting soil will have toxicity from excess nutrients if the excess water cannot drain out from the drainage holes.
The fertilizer that you add to the potting soil adds the required nutrients. Watering the potting soil releases the nutrients from the fertilizer if it’s a synthetic one. Or moves the fertilizer into the potting soil in case of an organic fertilizer.
You only want the required nutrients to be present in the potting soil and the excess to leach away. But plugging the drainage holes causes them to be trapped in the soil.
The excess nutrients will cause problems such as burning plant roots, yellowing leaves, stunted growth, or even death.
4. Loss of soil
We cover up the drainage holes to prevent the loss of soil. But, ironically, this can cause the pot to lose soil if you’re not careful.
This happens because the excess water may flow out from the top of the pot and take the potting soil along with it.
The easiest way to prevent this problem is to avoid filling the entire plant pot with potting soil and leave 1-2 inches from the top free. So even if you pour a lot of water in the pot, the excess will not cause the potting soil to flow out.
Should you use drainage hole plugs?
I don’t recommend using drainage hole plugs in regular use because that’s the same as not having drainage holes itself. The plugs will block the excess water from draining out and risk causing the problems I mentioned above, such as overwatering, salt buildup, loss of soil, or overfertilization.
If you use drainage hole plugs, take them off after you have watered the potting soil, and it’s been absorbed.
It may be good to use the drainage hole plugs the first time you’re preparing the plant pot with the potting soil to ensure the soil does not fall out.
I also find those useful if I’m sterilizing the plant pot for reuse before the next growing season. The plugs will help keep the bleach and water solution in the pot to kill the unwanted pests and diseases.