Without good drainage in pots with healthy plants, roots can suffocate, root rot (see my fixes) can become an issue and salt can accumulate to levels high enough to burn plants.
Suffice to say, it’s essential that any potted plants, either indoor plants or container plants in your garden, must have sufficient drainage for best growth, health and ultimately, be able to live longer.
Drainage Efficiency of Soils
The efficiency of a good potting soil mix is crucial for your plant’s health. Water needs to be able to move through the soil, across it and out, but just as important is how much moisture is retained in the soil.
Too much water and the roots will rot due to a lack of oxygen, yet too little water will cause your plant to starve to death.
What’s needed is an optimum level of drainage that allows sufficient water to be maintained, but not so much that the plant becomes waterlogged.
In an attempt to improve the drainage of potted plants, it’s all too easy take things too far.
Avoiding the Pitfalls of Excessive Drainage
When you realize there’s a problem with your plant pot drainage, a quick-fix is to bore some holes into the pot, thinking that’ll solve the problem. Sometimes, it can be, but it’s highly dependent on using the right soil in the pot in the first place.
Excessive drainage is not good because it’s likely going to leave your plant dehydrated, or you’ll find yourself watering your plant far more frequently than you need to.
Often is the case when you’re using sandy soils in containers, the water will drain fast, requiring frequent watering because sandy soils are incapable of water retention.
Clay soils, on the other hand, allow for improved drainage as these usually have at least 25% clay. All other particles in clay soils will be a mix of different soil types. This can be good, except outdoors after a rainy downpour because clay holds onto everything, not just water.
It’ll retain fertilizer for longer, but just as important to remember is it’ll also hold onto acidic content from rainwater too. For this reason, clay soils outside can be a problem in gardens, requiring the drainage to be improved to prevent a salt build-up that alters the soil acidity.
To improve the drainage in pots outside with clay soils, the trick is to add in some compost so that the clay doesn’t clump together when it’s wet. The clumps in clay soil are what will starve the plant roots of oxygen.
Mix in some organic compost and that’ll act as a sponge retaining more water that’s slowly released, as well as preventing soil clumping, which reduces oxygen flow.
For other types of soils suffering from excessive drainage where the water run off is too fast for the plant to absorb any nutrients, a drainage layer can be used.
This layer can be gravel, rocks, pebbles or activated charcoal as the main purpose is to put space between the pot base and the roots of the plant so the roots aren’t sitting in a puddle, which is when they will drown.
It’s worth mentioning that activated charcoal has microbial properties so it can be effective as a bug repellent too. Handy for any plants that are likely to be tormented by bugs.
Altering the soil is the way to improve drainage in potted plants without needing to bore holes into the plant pot.
How to Improve Drainage in Potted Plants Without Holes
An ideal plant pot is one with drainage holes, but not all containers have them. When they don’t, the most used option is to manually bore a hole through the bottom of the plant pot to improve drainage.
That’s something you may not want to do, particularly if your pot is made of ceramic as it can be tricky.
An alternative method is to double pot your plants. With double potting, you’ll have a smaller container with your plant and soil placed inside a slightly larger container.
A drainage layer (which they’re still known by, even though they don’t improve drainage) will be used in the large container just to give your plant some height so that it isn’t lost inside a container that’s clearly too big for it.
What to Use in Plant Pots to Improve Drainage
For plant pots that have the drainage holes, there’s still no guarantee those holes are going to be sufficient. Over watering your plants, or planting them in the garden where they’re later subjected to heavy rainfall, could cause the soil to turn to mud and block each of the drainage holes rendering them useless.
To stand the highest chance of increasing drainage in pots and keeping that drainage working, it’s best to line the bottom of the container with some material that’ll prevent the soil from turning into mud, keeping the holes functioning as they should.
Lining the bottom of your pot with styrofoam packing peanuts (link to Amazon) is the surest way to avoid clumping from getting in the way of drainage in a plant container used inside or out.
Another way that’s straightforward is to improve the drainage in your soil, while also improving the feeding quality for your plants, is by using coco coir compost (see on Amazon), which acts similar to sphagnum peat moss and Spanish moss to improve drainage, only with the added benefit of being slower release.
Coco coir can hold up to 10x its weight. It’s a really slow biodegradable so once it’s there, it’ll last a while before needing to be renewed. As it’s filled with organic matter, it’s ideal for a range of plants, including the edible types.
As coco coir is made of finer particles, it’s a good material to thin soil structures to improve aeration of your soil, and naturally because the particles are thin, it won’t clog up and block drainage holes.
What it won’t do is add any additional nutrition. However, the nutrition you do feed your plants, coco coir helps retain it for longer letting your plant get more from the nourishment you give your plants.
Growing up with a mom who filled her home (inside and out) with all sorts of plants, Lisa got her start in gardening at a young age. Living now on her own with a home and yard full of plants (including an indoor greenhouse), she shares all the gardening tips she’s gained over the years.