When you grow plants in containers, drainage is critical to plant health. The environments of garden beds versus pots are very different, making drainage much more of a challenge for potted plants. Ultimately, poor drainage and over-watering are the most common reasons potted plants die.
To ensure good drainage for potted plants, it is important to have drainage holes at the bottom of the pot. These holes allow water to escape and prevent water from pooling at the bottom of the container. Additionally, it is essential to plant your pot plants in well-draining potting soil that allows water to flow freely.
Do potted plants need good drainage?
Proper drainage is essential for all potted plants, even though some need more water and less drainage than others. Our advice in this post is fairly general, so you should do a bit of your own research to double-check the specific needs of your potted plants.
Provided plants in garden beds are growing in suitable soil conditions, the water should drain freely. But unless you ensure your pot plants have good drainage, excess water will sit at the bottom of the container, commonly resulting in root rot.
As the experts at the University of Illinois Extension state: “Wet soils favor root rot.” This is because they don’t leave enough space for air to get to the roots.
It really is as simple as that when you are container gardening.
What happens if your potted plants have poor drainage?
If your potted plants don’t have proper drainage, there are a lot of negative effects that may emerge. The most obvious one is that the soil in the container will become waterlogged.
Waterlogged soil will deprive your potted plant of oxygen. It doesn’t take much to realize that a lack of oxygen can lead to root rot and the eventual death of your plant.
When the soil remains excessively wet due to poor drainage, it becomes more compact and dense. This can suffocate the plant roots because it limits air circulation.
Excess water that accumulates in poorly drained pots can cause nutrients to leach out of the soil more rapidly. As the water drains away, it carries away essential nutrients, depriving the plant of the necessary elements for its growth.
Excessive moisture caused by poor drainage also creates a favorable environment for the growth of fungi and bacteria. These pathogens can attack the weakened roots and cause various diseases, including root rot and damping-off.
Sometimes poor drainage leads to salt buildup in the soil. When the water in the soil evaporates, it leaves behind salt and mineral deposits.
Over time, these salts tend to accumulate in the soil, causing salt toxicity. Salt buildup can also prevent the roots from absorbing water, which can disrupt the plant’s nutrient balance.
How to improve drainage in potted plants
The most obvious way to improve plants’ drainage is to use containers that have holes in the bottom. It stands to reason that drainage pots with holes will be likely to provide the best drainage possible.
If you have a pot or any other container that doesn’t have holes in the bottom, figure out a way to make a few holes so you can improve drainage.
But this isn’t necessarily the only way to ensure good drainage. Placing a layer of drainage materials at the bottom of the pot before you add soil can do wonders.
Sometimes people put coffee filters at the bottom of pots with drainage holes to stop the soil from falling through. This can help if the holes are big, otherwise don’t bother.
A drainage layer is another way to improve drainage potted plants need. Pebbles and broken bits of clay pots and similar drainage material generally work well.
But don’t rely on a layer of gravel at the bottom of a pot because it tends to gather soil just above the gravel. This doesn’t help drainage, but can rather make it worse.
Using well-draining soil for potted plant drainage is an obvious solution. In most instances, it will provide the drainage plant pots needed.
Then, you need to be sure you don’t overwater your pot plants. This human error is one of the main causes of poor drainage!
Also, when watering, add water slowly and evenly until it starts to drain out of the bottom holes. This ensures that the water reaches the root zone.
At the same time, it’s important to ensure that any excess water can escape. So, avoid leaving your pots sitting in standing water, as this can lead to waterlogging and root rot.
What to add to potting soil to make it drain better
You need to be sure that the soil in your containers really does drain well. Some mixes contain perlite, vermiculite, or coarse sand, so be sure to choose the right mix for whatever you are planting in your drainage container.
Perlite is a lightweight, porous material that we commonly add to potting soil to enhance drainage. It helps create air pockets in the soil that allow excess water to drain away.
At the same time, it retains some moisture in the soil that the roots need. Vermiculite is similar to perlite and it also improves soil aeration and drainage.
Coarse sand can also work well, as we explain in this post. It helps prevent compaction and allows water to flow more freely.
Incorporating organic matter like compost or well-rotted manure, can help improve drainage by improving the structure of the soil. It promotes better water absorption and aeration while enhancing nutrient availability.
Why is my potting soil not draining?
There are several reasons why your potting soil may not be draining. There may be a lack of drainage holes or those you have made may be blocked.
The container you have used may not be the ideal size. If your plant is in a pot that is too large for its root system, the excess soil can retain more water than the plant needs, resulting in poor drainage.
The soil in the pot may have become compacted. This will prevent water from draining effectively. It’s important to loosen the soil periodically by gently stirring it with a fork or a small hand tool to promote better drainage.
Just be sure not to damage the roots. You may not have used good-quality soil.
For instance, if it has a high clay content it won’t drain well. Amending the soil with materials like perlite, vermiculite, or coarse sand will usually improve its drainage characteristics.
Otherwise, you may be over-watering, or the plants may have become root bound.
Potted plant drainage is an essential ingredient for successful container gardening. By addressing the underlying issue, you can take appropriate steps to improve drainage and promote a healthier growing environment for your plants.