Why Houseplants Need Drainage and How To Drain Any Type of Pot

When getting plants, one of the first things to consider is what pot to choose. Does a pot need drainage holes or can I do without these? There are important factors to consider when dealing with adequate drainage for your potted plants.

Overall, drainage holes are essential to most plant types as they improve airflow, wash out excess water, salt as well as harmful substances and thereby decrease chances of root rot and soil diseases. Well-drained soil provides regular oxygen flow for roots to absorb water and nutrients effectively.

In this post, you will learn all about what drainage is needed for your plants and clever ways to create drainage even if your planters don’t have any drainage holes. Keep reading!

Drainage Holes For Better Air Flow to Prevent Root Rot and Soil Diseases

Do potted indoor plants really need these drain holes or can they do without? Indoor plants that are regularly watered certainly do need drainage holes to make sure they stay healthy.

Drainage for potted plants mainly imitates their natural soil conditions where water flows through, enables better airflow and prevents a build-up of harmful substances around the plant’s roots.

These are the main functions of drainage for potted plants:

  • Excess water to flow out (avoid plant roots from sitting in water)
  • Enhanced airflow in soil (providing carbon dioxide to roots)
  • Imitating the most natural environment for potted plants
  • Prevent the build-up of harmful substances in soil (such as too much salt, minerals, or toxins)
  • Prevent root rot and soil diseases by keeping soil humidity adequate

What Happens If You Don’t Drain a Plant: Roots Can’t Breathe Properly

It is commonly known that if you don’t drain a plant, the excess water can cause root rot and promote soil diseases from infesting the plant.

Though it is not mainly the water itself that destroys the roots. It is an intricate interplay between too much humidity, not enough oxygen as well as build-ups of harmful substances that damage the root system and causes it to rot over time.

Too much water in the soil destroys the air pockets within it, causing roots to slowly starve by lack of oxygen which they need to properly absorb water and nutrients. Roots literally breathe oxygen just like we humans do.

Good to Know: Root rot is not only caused by too much water. Rather, it is a complex issue depending on various factors. If you want to know all about how root rot damages a plant and how to recognize it, I found this explanatory video very helpful:

Why They Sell Plant Pots Without Drainage Holes: Decorative Outer Pots

Now that you know that indoor plants need drainage you will wonder why so many planters sold in stores do not have any holes at the bottom?

Indoor pots do not need holes if a second inner pot with drainage holes is used such as a nursery pot.

The plant pots without holes are meant as outer decorative pots while the plant itself rests within an inner nursery pot that remains largely hidden from view. If the inner pot has drainage holes, the decorative outer pot doesn’t need any.

Do All Potted Plants Need Drainage Holes?

As a general rule, all plants that are regularly watered need drainage holes. However, most arid plants such as succulents or cacti that only need few and irregular watering can be planted directly in pots without drainage holes.

Be Aware: Though these plants can do in pots without holes, it requires some experience and plant skills to avoid overwatering these plants. Hence, if you are a plant beginner or better want to be safe than sorry, I recommend using drainage holes for any type of plant.

Are Plant Pots With Holes Better?

Overall, plant pots with holes are more multipurpose and serve any type of plants whereas pots without holes often require adaptation or specific plant types for proper usage.

However, any pot without holes can be adequately drained with the right means.

Tip: Another aspect to be aware of when buying plant pots is not just whether they have holes, but also how deep the provided saucers are. Deeper saucers come in handier as chances of water spilling onto and damaging the floor are much lower.

How Much Drainage: Knowing What Drain is Adequate For Your Pots And Plants

Here’s some tips on how much drainage your plants need and what drainage holes are adequate.

Main Aim of Drainage For You: Be Able to Check on Your Watering And Pour Out Any Excess Water

A plant should always get as much drainage as is needed for excess water to flow out the bottom of the pot to prevent sitting in water. What is more, drainage should always be done in a way that allows you to check on how much excess water there is and pour it out if needed.

An example of bad drainage: Using a pot without holes and directly planting in it, with a filler layer of expanded clay or rocks as drainage, only does half the job. It may at first keep the plant from sitting in water, but as its roots grow, it will eventually reach the filler layer and the drainage effect will be lost.

In a directly planted pot, it will also be lost on you exactly how much water there is in it as you can’t access it and have no idea if there is any excess water or not – and trust me, with regularly watered plants there usually is some excess water.

Is One Hole Enough Drainage?

Drainage holes work well whether there is only one or several ones at the bottom of a plant pot.

What Size Should Drainage Holes Have: At Least 1/4 Inch in Diameter

Generally, drainage holes should measure at least 1/4 inch (= 6 mm) in diameter.

Holes larger than this need be covered with a filter, pebbles or broken pieces of pots to prevent soil from falling out. Smaller drainage holes of less than 1/4 inch (= 6 mm) in diameter are best covered with a layer of a filler substance, such as pebbles or expanded clay to prevent the soil or roots from clogging up the drainage.

Depth of Plant Saucers: Use Saucers That Are At Least 3/4 Inches Deep

I would recommend to avoid flat plant saucers and use saucers that are at least 3/4 inches deep. Deep saucers makes handling the plant as well as pouring out excess water much easier and it is an easy means to avoid spillovers of water that could damage your floor.

How to Plant in Pots Without Drainage Holes: Clever Ways to Create Drain for Plants

The need for drainage doesn’t mean that you can only use pots that come with holes and a plant saucer. There are several clever ways to create a drainage even when using planters without holes:

The Basic Technique For All: Use an Inner Nursery Pot to Provide Drainage

The most common and simple way to provide drainage in a pot with no holes is to double the pot by placing a fitting nursery pot inside the plant pot without holes.

This enables you to use decorative planters even if they have no holes. I also appreciate this method as it makes switching pots between plants very easy and comes in handy when it’s time to repot plants.

As all plants you buy come in a nursery pot, you don’t even have to buy that many new ones. Just keep all of them and you’ll soon have a variety of sizes at hand for repotting your plants later on.

This method can and should be combined with any of the below methods of creating further drainage space.

Tip: Often, it can be difficult to find nursery pots the right size to fit the decorative pots. Why not take a look at your kitchen waste: I found that many solid plastic containers from food packaging make great nursery pots. Just wash it, cut in some drainage holes with a knife or scissors and reuse that yoghurt pot as a nursery pot!

Are Plastic Pots OK for Plants?

Overall, plastic pots are not worse for plants than other types of pots. What needs to be considered is their age as well as the quality of the material. Old low quality plastic pots will give off more toxins into the soil and become brittle faster, especially when exposed to direct sunlight.

Compared to clay pots, plastic pots retain humidity for double the time. Plants therefore need less watering in plastic pots than they would in clay pots. Hence, it can be beneficial to plant humidity-loving plants in plastic pots rather than arid plants that prefer drier soil conditions.

Prevent The Soil From Clogging Up Drainage Holes: Add Extra Drainage to the Bottom of the Nursery Pot

Even if you use an inner nursery pot in your decorative planter, over time the soil tends to become dense and pervaded by roots which can clogg up the drainage holes, especially smaller ones.

To prevent clogging up of drainage holes, it is important to add some further drainage elements at the bottom of the nursery pot that loosen up the space around the holes and keep water flowing out freely.

What to Put in the Bottom of a Pot for Drainage?

There are various things that come in handy to create such a drainage filler layer to your pot:

  • Smaller, edgy rocks
  • Expanded clay
  • Broken pieces of old clay pots (my favourite!)
  • Pieces of shells (make sure to sterilize them before using)
  • Broken pieces of ceramic dishes
  • Upside down small kitchen sieves (without handles)

Note: Some experts recommend putting a layer of activated charcoal at the bottom of a pot as it has high absorptive as well as antibacterial properties. Personally, I wouldn’t rely on only charcoal to soak up excess water, especially as charcoal might be saturated over time. It can be beneficial though to add some activated charcoal into the soil mix when planting.

Lift Your Plant Up: Use Staging to Elevate the Inner Pot in the Planter

Now, just using a nursery pot inside a decorative planter is not quite optimal. You have to think of removing any excess water each time after watering, otherwise a small part of the roots might still sit in water.

Staging is an easy way to avoid this by placing an element at the bottom of the planter upon which the nursery pot then rests.

The staging element can be anything made of a durable and preferably natural material with a stable and flat surface:

  • A couple of flat rocks
  • Small pieces of concrete
  • Small pieces of brick
  • Upside down small plant saucers
  • Small pieces of a wooden shelf
  • Upside down flat, old ceramic bowls/trays
  • Upside down old kitchen colander or sieves (without handles)

Too Big to Drown: Use a Nursery Pot Slightly Too Big to Reach the Planters Bottom

Similar to staging, this method lifts up the nursery pot from the bottom of the planter. Not by placing an element below it, but by choosing a nursery pot that is slightly too big to reach the bottom. It will sit on the planters wall a bit above the bottom which leaves room for excess water to collect there.

The downside of this method can be that due to its size, the nursery pot looks out the top of the planter which can be aesthetically unpleasing.

The Hobbyist Way: Drill Holes Into a Planter

If you are a bit of a tinkerer and like to work with tools you may find it a good option to drill holes into a planter for drainage. It can work, but I do not consider this to be the best option for the following reasons:

  • Fragile material of planters: Many planters are made of ceramic or clay which will easily break when trying to drill them. You will have less issues with plastic or other synthetic materials.
  • Finding matching plant saucers: Decorative planters are usually meant to stand by themselves. If you drill holes into them, you might have difficulty finding matching and equally aesthetic plant saucers.

The Ideal Pot For Drainage: Benefits of Using Terracotta Pots

Terracotta pots are ideal plant pots when it comes to humidity and drainage. These pots not only come with drainage holes most of the times, but being made of clay they let air and humidity circulate through their walls which creates a really good environment for your plants. Clay pots breathe so to speak.

By releasing excess humidity through the clay as well as the drainage holes, the plant runs much lower risk of being overwatered and consequently will be less prone to root rot and soil diseases.

Aside from their circulation capacities, terracotta pots have many more benefits:

  • Eco-friendliness: Made of 100% natural clay material (no plastic)
  • Ideal weight: Not too heavy, but giving plants a firm stand
  • Age with grace: Old terracotta pots with patina on them look charming
  • Low costs: Simple terracotta pots don’t cost a fortune and are available anywhere
  • Diverse sizes: Terracotta pots come in a vast variety of forms and sizes
  • Multipurpose: Adequate for indoor and outdoor plants
  • Reusable: Even if they break, the broken pieces can be used as fillers and drainage in other pots

Of course, classic terracotta pots might not suit everyone’s style, though there are plenty of manufacturers these days creating very unique and modern clay pots. Personally, I really appreciate the rustic touch plain terracotta pots give to a room by creating a stronger connection to the outdoors with their earthy colour.

Please Note: Painted terracotta pots lose much of their circulation capacities as the porous natural surface is covered in paint. I hence recommend using plain terracotta pots.

While talking about all the benefits, I quickly want to point out some of the downsides these pots can have:

  • Fragility: Clay pots break more easily than other types of pots.
  • Better in cooler than hotter climates: Terracotta’s capacities of letting humidity out through their walls means that the hotter the temperatures, the sooner you will have to water the plant again. In hot summers or hot climates this can be an issue as you need to water more frequently.
  • Cracks through frost: When used outdoors, low quality terracotta pots tend to get cracks over winter.

Extra Tip: Always Empty Out Excess Water

Last but not least, here is one general tip to follow – whatever drainage system or pot you have chosen: Make sure to empty out excess water after watering your plants.

To do so, wait about 15 min after watering. Then check each plant for excess water and pour it out.

This is an important tip for all plants, as there exists no plant that constantly likes to sit in water.

Tip: You don’t have to waste the excess water. Collect it back into your watering can and use it next time you water your plants.

How Do You Keep Soil From Coming Out the Bottom of a Pot?

Prevent soil from washing out of a planter by:

  • Using pots with several small instead of one big drainage holes
  • Placing a filter, paper towel or piece of paper over the drainage hole
  • Place some pebbles or broken pieces of clay pots over the drainage hole

How To Know If My Houseplants Are Healthy?

Proper drainage can help prevent root rot and soil diseases, but there are other causes for pests and diseases that harm your houseplants such as low humidity or too much ventilation. It is recommendable to check on your indoor plants’ health regularly for signs of illness.

Read more on how to go about a regular plant health check in this post: Step-by-Step Houseplants Health Check with First Aid Tips

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