If you like to read about indoor plant growing, you’ve probably heard that you should only use pots that have drainage holes. What purposes do these holes fulfill, and why are they considered so important? Is it necessary for all indoor plant pots to have them?
All indoor plant pots should have drainage holes. These holes allow excess water to drain away, protecting your plant’s roots from rotting while simultaneously flushing out unwanted salts in the soil. However, it’s possible to compensate for the lack of a drainage hole with careful watering.
In the rest of this article, I’ll explain why drainage holes are so important, tell you how you can grow plants in pots without drainage holes, and answer some frequently asked questions. Keep reading to learn more.
Why Drainage Holes Are So Important
I recommend you use pots with drainage holes for all your indoor plants. These inconspicuous holes at the bottom of your plants serve the very important role of allowing excess water to escape.
This gives you much more flexibility with your watering cycles and allows you room for error. Let me explain.
Waterlogged Soils Kill Roots
You can hurt your plants by adding too much water to the soil – also known as overwatering. See, your plants have fragile roots in the soil that need oxygen – or air – to survive.
This is why you’ll notice that potting mixes tend to be fluffy and aerated rather than compact and dense. Roots need a constant supply of air, or else they’ll die.
Too much water in the soil prevents roots from accessing oxygen. Oxygen-deprived roots perish quickly; they die off and start rotting – this is called root rot.
Unfortunately, root rot is almost always irreversible once it sets in. If enough roots die off, the plant above the soil will most likely perish since it has no way of sourcing nutrients.
It also doesn’t help that water-saturated soils lead to root rot surprisingly fast. While conditions like low sunlight or dehydration take their toll on the plant slowly, hurting it over weeks or months before signs are noticeable, overwatering can kill healthy plants in as little as a few days.
Given how deadly overwatering is, it’s not surprising that root rot caused by waterlogged soils due to overwatering is one of the most common causes of the death of indoor plants.
Although root rot is most frequently caused by intense oxygen cut-off, it can also be caused by fungal growth. What’s interesting is that fungal growth is fueled by high moisture conditions. Saturated soils are a breeding ground for dormant fungi.
The danger overwatering presents is precisely what makes drainage holes so important. If you think about it, there are really no practical ways for excess water to escape a pot other than the drainage hole at the bottom.
Water does slowly evaporate into the air, but this process is so slow that it doesn’t really help you if you give your plants a little too much water by accident – And that’s very easy to do, especially when there’s no drainage hole. Even when the topmost layer of soil appears dry, there’s a good chance the soil below is still fully wet.
It can take days for any significant amount of water to evaporate from the soil and leave the pot. By the time it does, the damage will already have been done.
Drainage holes allow you to water the soil deeply and thoroughly, with confidence that you won’t cause damage to your plants.
Deep waterings are much preferable to shallow, more frequent waterings because they encourage your plants to dig their roots deeper into the soil in search of water. Ultimately, you end up with a stronger, healthier plant.
You can find useful information about proper watering in this guide. You’ll also learn how to reduce water loss naturally and conveniently, so you can water your plants less frequently without having to worry about them falling thirsty: How to Keep Indoor Plants from Drying Out (6 Methods)
Protecting Your Plants From Overwatering
Now that we’ve looked at how dangerous overwatering is, let’s look at some steps we can take – in addition to using pots with drainage holes – to help prevent your lively plants from suffering this cruel fate:
- Use high-quality potting mix. You don’t want to be saving an extra few dollars with your potting mix, especially if you’re still new to indoor gardening.
- Add organic matter to your potting mix. Organic matter improves soil aeration and water drainage. Not only that, but it also adds nutrients to the soil.
- Look up how much water your plants need. Be sure to account for temperature and climate – plants need less water in winter. You should let the soil dry out briefly between waterings with all but the most water-demanding plants.
If you just started out with indoor plant-growing, you should know that your plants probably don’t need as much water as you think.
We often overestimate how much water plants need. It’s also easy to blame a lack of water for unknown health problems.
Remember that underwatering, while undesirable, won’t kill your plants the way overwatering will.
Proper Drainage Prevents Salt Buildup
There’s an additional benefit to having a drainage hole. Water flowing through your soil ensures that salts and salt compounds are removed before they become a problem.
A moderate concentration of salts in the soil is inevitable. Even tap water contains salts, fluorides, and the element chlorine as a disinfectant.
Things become problematic when salts are allowed to build up to high concentrations. This is bound to happen sooner or later if
- Your pot doesn’t have a drainage hole. Salts won’t be flushed out by water.
- You use softened water. This often leads to a buildup of sodium.
- You regularly use nutrient-rich fertilizer. Don’t get me wrong; fertilizers are great for your plants. But some fertilizers, especially inorganic ones, can contain harmful compounds in minute amounts.
Too many salts can make the soil environment unsuitable for your plants. And while damage is usually moderate and slow to set in, it would be preferable to have your potting mix be free from toxic salt build-ups.
Pro-tip: Some plants, such as spider plants, are more sensitive to the salts (and chlorine) in regular tap water than the average plant. Even if you’re using pots with drainage holes, it’s advisable to water salt-sensitive plants with boiled – or better yet, distilled – water.
Making Use of Pots Without Drainage Holes
If you have a pot that doesn’t have a drainage hole, don’t worry. It’s not obsolete just because it doesn’t have a drainage hole; there are a few clever ways you can put it to good use.
Drill a Hole in Your Pot
The simplest thing to do with a pot that doesn’t have a drainage hole is to drill one into it. At first glance, you may think this is impractical, but it works very well.
Ceramic is easy to drill through, so most drills will be able to create a sizable hole in a matter of seconds without causing any damage to the rest of the pot.
You only need to create a single hole, and it doesn’t need to be wide. You can drill two holes for better drainage if you have an exceptionally large pot.
I don’t recommend creating multiple holes because it doesn’t yield much additional benefit, and you increase the risk of damaging your pot.
Let me walk you through the process step by step:
- Turn your pot upside down. Do not use an unsteady surface.
- Start your drill. Let it get up to speed before it comes into contact with the pot.
- Make contact with the pot and let the drill work its way through the ceramic. You can hold the drill at a slight angle to increase the size of the drainage hole you’ll get.
- Don’t put too much of your weight on the drill, or you risk cracking the pot. Press gently. This should only take a few seconds.
- Use gloves and safety goggles. It’s standard procedure when operating a drill.
Here’s a video if you’d like to see a practical demonstration of how it’s done.
Go With Double Potting
As the name suggests, double potting is putting a pot in another pot. This is ideal when you have an aesthetic pot you wish to use as decoration, only to realize that it doesn’t have a drainage hole.
In this case, you can grow your plant inside a container with a drainage hole and then place that container inside the pot without a drainage hole. The interior container is the grow pot, whereas the outer pot is the cachepot.
Of course, the cachepot will need to be larger than the grow pot. Getting the dimensions right can be a bit iffy. But once you do, you can show off the decorative flair of your cachepot without having to drill a hole into it, all while reaping the full benefits of having a drainage hole.
You should line the bottom of the cachepot with gravel or pebbles so that the interior pot remains suspended above the escaped water. There’s no point in double potting if the escaped water remains in contact with the drainage hole.
When you need to water your plant, remove the inner container from the cachepot and water it thoroughly over a sink. Let it sit for a few minutes to allow the excess water to drain away.
Once the water stops exiting from the drainage hole, you can place the container back in the cachepot.
Water will slowly collect in the cachepot. Make sure to empty the cachepot before the water rises to the point where it’s making contact with the bottom of the grow pot.
Growing a Plant in a Pot Without a Drainage Hole
We’ve talked a lot about why having a pot with a drainage hole is important. That said, it is very much possible to grow plants in pots without drainage holes and not have them succumb to overwatering.
I don’t recommend it, though.
First and foremost, you should take the steps we discussed earlier. A high-quality potting mix, the presence of organic matter, and correct watering routines become all the more important when you’re compensating for the lack of a drainage hole.
You should avoid watering deeply in this case. And, generally speaking, be much more conservative with the amount of water you give your plants. Air on the side of caution.
You should also avoid using inorganic fertilizers or softened water. As mentioned earlier, both of these products contain large quantities of salt compounds and will eventually lead to a salt buildup in the absence of water flow through the soil.
Don’t skip out on fertilization entirely, though – it’s a vital part of the growth process. Use organic fertilizers instead. You can make healthy, high-quality compost at home using just a compost bin. It’s free, and it’s effective.
A popular practice when growing in a pot without a drainage hole is filling one-fourth with rocks and pebbles. Since pebbles are irregularly shaped solids, they leave behind empty volumes for occupation. Water can seep through and settle into the tiny spaces between the pebbles.
This clever little construct certainly helps keep overwatering at bay, but to nowhere near the extent a proper drainage hole or even a cachepot would.
There’s also no way to flush out the water that collects between the pebbles. Once the empty volume at the bottom fills up, any water in excess will remain in the soil as it would in a regular closed-off pot.
Filling up one-fourth of your pot with pebbles also means you’ll have less soil in the pot for plant growth.
You’ll either have to use a larger pot to accommodate the pebbles or settle for the decreased nutritional reserves your plant will have access to in the reduced amount of soil.
Watch Out for Rain
Without a drainage hole, the soil in your pot will quickly reach its maximum saturation level when it rains. You should bring all such pots indoors until the weather returns to normal.
Pots without drainage holes aren’t unfit for outdoor growing, but you risk a surprise shower killing your plants when you leave them unattended.
This makes growing full-sun-loving plants in non-draining pots slightly more problematic if you live in a rainy region.
Frequently Asked Questions
Here are some frequently asked questions about pots and drainage holes and their answers.
Won’t the Drainage Hole Make a Mess?
Drainage holes release muddy water. Most indoor plant pots with drainage holes are kept in saucers or cachepots. These external containers hold the released water and can be cleaned conveniently.
Is a Single Drainage Hole Good Enough?
A single drainage hole is all your indoor plant pots need. If you’re drilling your own drainage holes into a container, I recommend you create only a single hole. Creating multiple holes provides little benefit in how effectively excess water is released from the container.
Are There Any Plants That Can Be Grown in a Pot Without a Drainage Hole?
Some plants – typically ones that grow in water-rich environments such as shorelines and rainforests – are better able to tolerate waterlogged soils than the average plant.
For example, the Devil’s Ivy and the Spider Plant are resilient enough to water damage that they can be grown in pots without drainage holes with proper care.
That said, a pot without a drainage hole is simply never better than one with ー for indoor gardening, at least. Even though some plants can survive having their roots submerged in water, it’s still a suboptimal growth environment.
The good news is that almost all modern indoor pots come with built-in drainage holes from the get-go.
How Do I Keep Soil From Falling Out of the Drainage Hole?
It’s uncommon for soil to fall out of the drainage hole, but it’s not unheard of. Usually, it’s either because the drainage hole is too wide or the potting mix has not had the time to settle down firmly.
The best way to prevent unwanted soil drop-off is to cover your drainage hole (from the inside) with an object that lets water through but keeps the soil inside.
Gardening sheets, coffee filters, and mesh linings. You can even get away with using newspapers in a pinch. The only criterion is that your soil blockade needs to let water flow out efficiently.
How Can I Identify Overwatering?
Here’s what to look for:
- Wilting leaves that don’t recover when watered
- A loss of color
- Stunted growth
- Soft and limp plant body
- Black roots
If you suspect overwatering, dig into the soil to examine the roots. If you notice brown/black or soggy roots that smell bad, it’s probably root rot, an issue caused by overwatering.
Drainage holes allow excess water to leave the soil, thereby preventing root rot – a life-threatening condition that causes irreversible damage to plants. If you have a pot without a drainage hole, I recommend drilling one into it.
You can also use said pot as a cachepot along with a separate internal grow pot to host the plant. Growing plants in pots without drainage holes is possible with meticulous care but not recommended.
Some plants are more resilient to water damage than others; the Spider plant and the Pothos are two common examples of such plants.