Ultimate Guide - Drainage For Potted Plants

Do Planters Need Drainage?

There are a couple of different schools of thought on this topic. Some are hard and fast, a planter must have drainage holes, but some people feel that placing other materials under the growing medium, in the bottom of the container, can create sufficient drainage. The vast majority of plants do not like to sit in wet, soggy soil. This can damage the roots, affecting absorption of nutrients and restricting air flow.

For outdoor plants and flowers, some routes allowing water to dissipate may be critical, especially in a rainy climate. Controlling how much rain falls into your container is difficult, if not impossible. 

For indoor pots, having non drainage at the bottom can make things easier, but it makes watering the plants with the right amount of water extremely important. Because if you add too much water, the roots won’t dry out fast enough and could rot, eventually killing the plant.

How Much Drainage Does a Planter Need?

If you’ve determined your plants need well draining pots, how many drainage holes are necessary? That depends on how big your container is and what it’s made of. If you need more than one drain site, be sure they’re evenly spaced to allow uniform drying of the soil.

Wood, clay, or terracotta materials are porous and also absorb some moisture, so one drainage site is usually sufficient.

Glazed terracotta pots, fiberglass, plastic, glass, and metal containers are different though, they’re not porous. Although one hole is enough for a planter 6 inches or smaller, three or more holes for water to escape through are necessary for larger pots. 

What to Do if A Planter is Not Draining

If your soil isn’t draining well, even in a pot or planter with drainage, it may be filled with traditional soil. They can be repotted, very carefully and without disturbing the root ball or the soil contained within. Placing potting mix underneath and around the original root ball can help. Studies have found that using a “potting mix” rather than regular soil, is beneficial to your plants.

Potting mixes are actually soil-less and will contain materials such as coconut coir, vermiculite, perlite, and/or peat moss. These materials are lightweight and allow for the water to easily travel through them, and the air to flow, allowing for healthier roots. Though not quite as effective, but less expensive, coarse sand may be added, also.

Creating Drainage For A Planter

There are a few things you can do to create or improve drainage for potted plants. First, check to make sure that your potting soil drains well. Typically, soil and dirt from outside does not do well as potting soil, because it does not drain as well. If the soil isn’t draining well, consider repotting the plant with better draining potting soil, designed specifically for garden planters.

Making Drainage Holes In A Planter

Step 1 - mark where you want the hole(s). Place one hole in the center, and if more than one is necessary, take care to evenly space them around and near the perimeter of the container. 

Step 2 - depending on the material of the planter, create the holes using specific methods.

Ceramic or terracotta pots - using a drill, a diamond tipped hole saw bit (we recommend ½ to 1 inch bits but they’re inexpensive!), and a little water, you can quickly drill through the ceramic. Start by pouring a small amount of water on the spot where you’re going to drill, to prevent overheating. Place your drill bit at about a 45 degree angle, until you get a good start into the ceramic. Once you have your start, stand the bit up straight, apply a little pressure (drop some more water on there if you need to) until your bit drops through to the other side.

Plastic or fiberglass pots - You can use 3 methods in order to create the holes. Melt holes into the material using a soldering gun. Apply some pressure on your marks, until the tip melts through the plastic. Depending on how thick your plastic is, it shouldn’t take long. Or you can use a hammer and a nail large enough to create a hole big enough for water the leech through.

You may need to support the pot with something on the inside, so it feels like you’re hammering into something, and the pot doesn’t just bend away from the hammer strikes. Using a drill and regular ½ to 1 inch drill bits makes quick work of this. Place your bit on your marks, apply a little pressure, and before you know it, you’re through the plastic and have drainage in your container.

If you’re drilling or hammering, be sure to wear eye protection, as shards of your pot may fly off and injure your eyes.

Step 3 - sand off any rough edges so you don’t get cut when moving and carrying the planter or container.

Step 4 - you may want to put coffee filters inside the planter at the bottom before you fill it with soil. This is especially helpful for larger holes so the potting soil doesn’t fall out through the holes and make a mess.

Growing Plants in Pots Without Drainage

Proper drainage for pots, whether it is indoors or outside is very important. It is very easy to overwater a plant without drainage. In that scenario, the roots won’t dry out fast enough and will rot. If the problem lasts long enough, the plant will die. 

If your container doesn’t have drainage, and you’d rather not create drainage, there is another option! You can place a draining pot, a bit smaller, inside of it. If you’d like, you can cover up the fact that it’s a pot inside a pot, by placing sphagnum moss, or something similar, around the top. That is the best solution for planters without drainage.

Using Rocks For Drainage in Pots

There is a bit of controversy surrounding this subject. Some suggest that you can place pebbles, rocks, empty plastic water or soft drink bottles, packing peanuts, cardboard (the list is endless) in the bottom of your plant pots, to allow the water to drain away from the soil and protect the roots from damage or root rot. Others maintain this is untrue and believe water has some difficulty transferring from the soil down into the “protective layer” and the roots end up sitting in soggy soil, anyway. 

If you have decided you want to plant your plants in a container that doesn’t have drainage holes, here are some things you can do to create a bit of a water well in the bottom. You’ll still have to be very careful not to overwater, you don’t want a ton of water sitting in there. 

Place small landscape rocks or pea gravel in the bottom of your chosen vessel, an inch or 3, depending on the size of your container, will be plenty. On top of the rocks, but not completely covering them, a thin layer of horticultural (or activated) charcoal. The charcoal allows water to drain through and into the rocks, helps absorb extra water, provides nutrients for the roots and contains natural microbial that can help avoid bacterial and fungal issues. Add your soil, your plant, more soil around the plant, gently firm that soil up, and then water your plant.

There is a large variety of other items people use to create drainage (and fill space in the bottom of a planter so not so much soil is needed.) Empty plastic water or soft drink bottles, Styrofoam packing peanuts, pieces of broken terracotta pots, and the list goes on.

Growing Succulents in Pots Without Drainage

Good drainage is particularly important for succulents, they definitely do not like wet soil. Succulents store water everywhere they can, leaves and stems, right down their roots. If they’re sitting in water too, it is a fast track to rot. It is paramount to use a growing medium intended for succulents as well as provide good drainage for them, either by using containers with a way for the water to make its way out.

How to Plug a Drainage Hole

If your pot has drainage holes and you don’t have (or don’t want) a saucer under it, you can try to plug the drainage holes. Sometimes a coffee filter at the bottom will slow, but not stop, the water from draining. It will help keep the soil inside the pot though. You can also completely cover the hole by using duct tape or a sticker over the hole. Rubber and plastic stoppers work the best to plug drainage holes though. You make sure it doesn’t make the bottom of the planter unbalanced if you use a stopper.

Indoor Plants That Don't Need As Much Drainage

There are a number of plants that prefer wet or moist conditions and/or can do well in planters without any drainage. Care must still be taken not to overwater. Depending on where you live, most of these can be grown indoors, outdoors, or outdoors in the summer months and inside during the colder months of the year.

  • Cordyline
  • Oleander
  • Schefflera
  • Zamioculcas zamiifolia (Zz Plant)
  • Pothos
  • Dieffenbachia
  • Spider plants
  • Horsetail Reed

Why Make Pots Without Drainage Holes?

Many plants are planted in pots without drainage, by growers, simply because retailers show a preference for them or even require them. On this larger scale, no drainage means less mess for retailers to deal with while staff water and care for a large number of plants.

Decorative pots often have no escape route for water and are often intended to be used as a cachepot (a hiding place for another planter.)

Chris Link Profile Pic

Author Chris Link - Published 3-04-2022