by Matt Gibson
Drainage is one of the key factors concerning growing healthy plants. A lack of drainage can lead to lots of problems, including root rot, mildew, and stagnant (and therefore stinky) water. None of these is a good thing when it comes to successful gardening in containers. It’s unfortunate that there are so many beautiful containers on the market that have no drainage holes—and even worse, many of these containers are made out of materials that would make drilling your own drainage holes a very risky, if not impossible, operation.
So, is there a workaround? Well, the first question is, can you drill your own holes into the container you have your eye on safely and without damaging it? Even glass and ceramic containers can be drilled into if you have the right tools on hand. However, when drilling is not an option, can you still make a container without drainage holes work for your plants?
Most experts say no—gardeners shouldn’t even attempt to grow plants in a pot without drainage holes because it is simply not worth the hassle. Others say yes—it is possible to successfully grow plants in pots without drainage holes, but only if you follow a certain process involving layers of gravel, pebbles, broken pottery, or other coarse materials. Still others warn that a protective layer of rocks or pebbles does not offer enough drainage to keep your plants happy in the long run. You may have heard another faction of experts insist that gardeners also need to add activated charcoal in a layer at the bottom of the container to assist with absorption of excess water.
There are a handful of coastal plants and a few aquatic plants that actually enjoy having their roots submerged, so you could opt to grow one of those in a pot without drainage holes. However, these plants are most likely not what you intend to grow, so you will need to focus insteadon a solution to your drainage problem.
Why Are Drainage Holes so Important?
Every plant in the world requires water to survive, yet overwatering is one of the most common culprits when a gardener’s plants die—especially when those plants are grown indoors. Drainage holes provide an exit route that allows excess moisture to seep out after a plant has been watered. Without drainage holes, any extra water collects at the bottom of the pot. When this happens, the plant’s roots end up constantly submerged in the water at the bottom of the container, making them susceptible to rot as well as fungal and bacterial afflictions.
Allowing a pool of water to collect at the bottom of the container can also keep the roots of a plant from being able to access oxygen, which of course, plants need to survive. Another important issue resulting from lack of drainage is an accumulation of the natural salts and other minerals that build up in soil and need to be flushed out. Fertilizers are chock-full of salts and other minerals that are great for feeding your plants but can be very harmful to the plant’s root system if they are not washed out and instead are allowed to build up at the bottom of your pots.
Solution #1: Double Potting
There is yet another brilliant workaround that, in most cases, seems to solve the problem of drainage when containers don’t have holes, allowing you to use any beautiful container you find without damaging it by drilling holes into the bottom or fussing with pebbles, charcoal, and all the rest of those steps. It’s so easy, you won’t believe you haven’t thought of it sooner. You can simply plant your young plants or seeds in a slightly smaller pot than the container you’d like to use—one that has drainage holes—and then place the smaller container inside of the beautiful but drainage-hole-lacking pot that you so desperately want to put to use. Then, when the pot your plants are growing in drains into the pot that has no holes, you can simply remove the smaller pot, pour the water out of the larger, pretty pot, and then place the smaller pot that contains the plant back inside. Using this method should avoid any drainage issues, assuming you don’t forget to dump the collected water out on a regular basis. This simple technique is called double potting.
While double potting might be the simplest solution, it’s not always the easiest one to carry out. For example, sometimes that pretty pot that has no holes, the one you really want to use, may be irregularly shaped and won’t hold a smaller planter inside of it easily. With that in mind, let’s dive in a little deeper, identify why drainage is so important anyway, and then take a more in-depth look at all of the available options gardeners can use to solve this problem.
Solution #2: Creating a Drainage Layer
Some experts warn against creating a drainage layer out of gravel, broken pottery, or other coarse materials at the bottom of gardening containers to compensate when a pot has no holes. You may have even heard this solution called a myth by those who say excess water will not have sufficient drainage between the soil layer and the rock or pebble layer and will basically pool at the bottom of the soil before it ever drains into the rocks. In that case, this solution would still leave the roots of your plants susceptible to root rot.
Here’s the crux of the matter: Water tends to hang out in the soil for a while before draining into the pebble layer, but it will eventually drain into the bottom. The issue is how long it takes for moisture to travel from the soil into the drainage layer and whether the plant’s root system will become too saturated before the water drains away. Unfortunately, these answers are anyone’s guess, and they have to do with the exact placement of the layers and how intermingled they are.
When using this method, the best results come from a gradual transition from soil to pebbles (or other drainage material). Mixing some pebbles into the bottom layer of soil in your container can help the drainage function as it should. Though the drainage layer method has had mixed results, some gardeners have used this technique successfully for decades. With that in mind, we’ll let you know exactly how to do it correctly so that you can avoid any potential pitfalls.
First, create a drainage layer at the bottom of the pot you wish to use by adding pebbles, stones, broken pottery, or pumice to the bottom of the container before layering in the soil. You want this layer to be evenly distributed across the bottom of the pot so that excess water can drain into this section and away from the plant’s roots. Compared to the coarser, looser drainage layer, soil is tightly packed and has less space for oxygen to circulate, so your drainage layer should provide an easy escape route for excess water to drain into after it’s moistened the soil above. To ease the transition of the water when draining, add a few pebbles to the bottom layer of the soil as well.
Pro Tip: Use Activated Charcoal
Adding a healthy dose of activated charcoal to your drainage layer (or even making your drainage layer out of nothing but activated charcoal) could be the answer to the drainage hole problem. Activated charcoal is a great natural absorbent and can remove a surprising amount of excess water when there is no other escape route for the moisture. Activated charcoal also has natural antimicrobial properties, which can fight against fungal and bacterial issues that could plague your plants as well as deterring pests.
Solution #3: Drill Your Own Holes
This solution won’t work for every pot you come across that has no drainage holes, but it will work for a lot of pots as long as they’re made out of certain materials—and as long as you have the right tools. You will need a nice electric drill, half-inch drill bits (normal, masonry, or glass bits may be required depending on the type of pot), some scrap newspaper, a nail, painter’s tape or masking tape, a permanent marker, and a pair of goggles for safety.
Most materials can be drilled into without destroying the whole pot in the process if you use the right drill bit. However, when you love a container and don’t want to take your chances damaging it, we suggest you try one of the other methods suggested here. If you are determined to put a few holes of your own into a pot without drainage, though, here’s how to do it.
First off, you need to determine the appropriate bit to use in order to create holes in your container. If your pot is made out of metal or plastic, a normal drill bit should suffice. If your pot is made out of unglazed ceramic, a masonry bit is required. If your pot is made of glass or glazed ceramics, a tile or glass bit will be needed to do the job. Once you’ve got the right bit, insert it into the drill, and get ready to drill your holes.
Spread out a sheet of newspaper on a flat, level surface, then place the pot upside down on the newspaper. Mark the spots where you want to drill your holes with a permanent marker. You will need one rather large hole in the center of the pot at the very least, but larger pots may need up to three drainage holes. In this case, mark the three holes with the permanent marker in a triangular pattern near the center of the base of the pot. Mark each hole about two inches apart from the other holes.
Mark each spot further by making a small indentation where you’ll drill with a nail. This will give the drill bit something to hold onto so that it doesn’t slip and create a hole in a place you didn’t intend. If you are drilling into a glazed ceramic pot, you will want to cover the spot where you’ll drill with a piece of painter’s tape or several pieces of masking tape to assist in keeping the drill bit from going astray.
Lastly, don your safety goggles before you get to drilling. Be sure to hold the drill upright so that the bit is perpendicular to the pot base. Start very slowly, applying a light amount of pressure, and drill at the lowest speed to avoid damaging the pot. After you’ve drilled the holes where you marked them, remove any tape, and rinse the residue of the pot’s material that you created from drilling from inside and outside the container.
So there you have it—three methods, each with their own merits and times when they’re most useful, to get containers without functional drainage holes ready for gardening. If you decide to grow your plants in containers without holes, even if you’re using the drainage layer method, you may want to consider dumping excess water out of the container from time to time. Just use your hand to hold the majority of the soil and the plant itself in place, then turn the pot upside down to allow any accumulated water to drain out.
Even with the best possible setup, standing water in a container can stagnate and cause the roots of the plants inside to get too wet. It’s not a bad idea to dump that water out from time to time as explained above, even if you lose a little bit of soil in the process. Soil can be replaced, but damaged roots cannot be repaired. Also, be sure to never place containers with insufficient drainage outdoors, as you will not be able to control the amount of rainwater they will receive. These containers are best suited for indoor gardens. And of course, if none of the methods illustrated here solve your problems, don’t hesitate to repot your plant into a container with proper drainage.