Have you gone shopping for plant pots, only to fall in love with an ornamental pot without a drainage hole? We’ve all been there.
The plant pot fits in perfectly with our decor and is even at the right price. Meanwhile, the pots with drainage holes look plain in comparison. So we ask ourselves, do we really need drainage holes?
Yes, you need drainage holes. They can make the difference between a dead plant and one that will live with you for years. Drainage holes allow water to escape to prevent over-watering and root rot. It’s very difficult to save a plant once root rot sets in.
However, just because a pot has a drainage hole, doesn’t mean that your houseplant will drain well. Other factors can keep the potting mix too moist, like not having enough coarse material (such as perlite) in the potting mix, compacted potting mix, the material of the pot, and your watering habits overall.
In this article, we’ll talk about why plant pots should have drainage holes and what to do if they don’t. We’ll also discuss other ways to improve drainage, separating myth from fact.
Drainage Holes For Plants Pots
Should Plant Pots Have Drain Holes?
Yes, plant pots should have drainage holes! While plants need enough water to survive, if they have too much, they’ll die.
While normally we think about roots taking up water, they also take up oxygen. The spaces between soil aggregates allow air to reach the roots.
This space is also where water flows – or, if there’s nowhere for the excess water to flow, where it sits. Fungal infections can take advantage of the moist conditions.
Both a lack of oxygen and fungal infection can lead to root rot, and once plants succumb to it, there’s little you can do. Some plants are more susceptible than others, depending on their soil moisture preferences.
Soggy potting mix can also attract common plant pests like fungus gnats or grow mold.
Outdoor pots always need drainage holes if left unprotected from the rain. You can’t control how much water the pot will receive, and a hard rain may drown your plants.
Even if you promise yourself that you will never overwater, you may end up underwatering to avoid it. Some plants that like it on the drier side may do all right with that kind of treatment, but you’ll have a hard time with plants that like more moisture but hate sitting in water. Even houseplant experts have difficulties with growing in a drainage-less pot.
How Big Should Drain Holes In Plant Pots Be?
Keep drainage holes between ¼ inch and ½ inch big. Anything smaller than ¼ inch may get clogged up with soil and anything above ½ inch may let soil fall out.
Some people may go up to ⅝ inch, but those are mainly for outdoor containers. If the plant pot you have has bigger holes, then line the bottom with a coffee filter.
The size of the drainage hole doesn’t have any noticeable effect on how fast the water drains. Some gardening websites offer tables with how big and how many drainage holes for which size pot, but in the end, it won’t make a noticeable difference.
What Do You Put In The Bottom Of A Planter With Drainage Holes?
You don’t need to add anything to the bottom of a planter with drainage holes. Very little soil will fall out, and if it does, it’ll fall into the saucer underneath.
If you’re concerned that your drainage holes are too big, then cover the bottom with a coffee filter. The water can still flow out easily while soil can’t.
Don’t put perlite, gravel, sand, pebbles, or pot shards in the bottom. Numerous gardening books and websites tell you that lining the bottom of a plant pot with gravel will improve the drainage, but science just doesn’t back up this myth [PDF].
When water moves between layers of fine textured material (like potting mix) to coarser textured material (like gravel or sand), water slows down and remains in the fine textured material just above the coarser material.
The coarser the material, the more water remains in the fine material. More water will stay above pot shards than gravel, and more above gravel than sand.
Adding a coarse layer also reduces the amount of area that roots can grow, so your plant won’t grow as large.
The bottom line: Adding gravel at the bottom of your pot won’t prevent your potting mix from getting waterlogged – it will cause it.
Why Do Some Pots Not Have Drainage Holes?
Plant pots without drainage holes are actually called cachepots or jardinieres. They’re an ornamental pot that’s used to hide the actual pot that the plant grows in (the one with the drainage hole).
Cachepots are smaller and meant to be displayed on tables, mantels, or shelves. Jardinieres are larger and meant to sit on the floor either indoors or outdoors. Either may come with a decorative saucer.
Since cachepots don’t have drainage holes, any excess water will remain at the bottom just like it would a saucer. If your cachepot is taller than the nursery pot, put gravel at the bottom of the cachepot to hold the nursery pot above the excess water.
The excess water should evaporate. You can also either remove the nursery pot to water it in the sink or tip the excess water out of the cachepot after watering.
Cachepots have many advantages:
- You don’t have to repot when buying new plants.
- You can easily switch out plants, giving you greater flexibility.
- You can rotate the nursery pot to provide light to the other side of the plant so it grows evenly, without rotating the cachepot.
- It’s easier to move since you can move them separately (especially important with very large plants and heavy cachepots/jardinieres), and if you move houses, you don’t need to repot them into plastic nursery pots.
- If your plant is too small for the cachepot, you can use other pots or saucers to bring it up to the right height, and continue to use the same cachepot even as you repot the plant in larger containers.
Unfortunately, retailers don’t differentiate between a plant pot and a cachepot. When shopping in person, that’s not a problem, as you can check for drainage holes before buying.
Online, it’s a different story. They may not clearly label what has a drainage hole and what doesn’t, and a matching saucer doesn’t help as both can come with one.
Look for clues in the description. Some retailers may include what size of plant pot it fits or a note to combine it with a plant pot.
Sometimes they’ll even show photos and tell you that you can plant a pot directly inside. If it’s a very ornamental pot, it’s probably a cachepot.
How To Use A Pot Without A Drainage Hole
Just because a pot doesn’t come with a drainage hole, doesn’t mean you can’t use it. Great options include:
- Keep your plant in a nursery pot that fits inside the ornamental pot, using some gravel to raise the nursery pot above the bottom so it doesn’t sit in any excess water.
- Drill your own hole into the bottom of the pot. Be careful, since plastic pots may crack along the bottom. Ceramic pots require a special drill bit.
- Set the pot in the sink to water, leave it for a few minutes for the water to fully saturate the soil, then tip it on its side to let the excess water drain out. Loose soil may tip out, but if it’s moist and patted firm, then it should hold up. This method can be tricky and takes more time, so keep this as a last resort.
- Remove or poke a hole in the decorative plastic or foil around a gifted plant.
Other handy care tips for pots without a drainage hole include:
- Use filtered water instead of tap water, especially if you have hard water or chlorine.
- Avoid using fertilizers when possible.
- Wait until the top layer of soil has dried before carefully watering again.
What Type Of Plants Don’t Need Drainage?
Some plants do better than others in pots without drainage holes. Plants that like to have perpetually moist soil may still not like to sit in water, so while it seems like they’d be ideal for this type of pot, they may be the hardest to maintain.
Bog plants do well in drainage-less pots, as their preferred condition is – you guessed it – sitting in water. There aren’t many bog plants commonly used as houseplants, but some well-known species include carnivorous plants like sundew, venus fly traps, and pitcher plants.
Carnivorous plants don’t need to be fertilized and they’ll also catch any fruit flies and fungus gnats you have.
Cacti and succulents can actually do well in drainage-less pots so long as you barely water them! They need very little water and prefer dry soil, so let them dry out completely in between very light waterings.
Some beginner friendly plants like spider plants and snake plants can also survive in a pot without drainage as they can recover quickly from over watering.
3 Ways To Improve Drainage In Plant Pots
While drainage holes are essential for having drainage in the first place, you may still end up with too-moist soil, especially for those dry-loving plants.
Cut back on watering
Is it poor drainage or is it too much water, too often? If you water your plant frequently before the top inch of soil has dried, then the best method is to cut back on how often and how much you water. And make sure you empty the saucers!
Mix amendments like vermiculite, perlite, or coarse sand into your potting soil
The biggest reason for soggy soil is that the potting mix components absorb too much water. Not a problem for plants that like to keep moist, but dry-loving plants will hate this, especially if you water again before it’s dried out.
Mixing in coarser non-absorbent materials like perlite will provide more space for water to move freely without being absorbed. But don’t use this as a solid layer at the bottom, as you’ll only exacerbate the problem (as discussed above).
Always use a succulent or cactus mix when growing succulents and cacti – they’re designed to drain water away and stay dry, just like our little succulents want.
Repot into a pot made from a different material
Plastic pots can help you go longer between watering, as they only lose moisture from the drainage hole, but if you find that your soil stays too moist for the plant’s preferences, switch to unglazed terracotta.
The terracotta will wick away moisture from the potting medium, allowing it to dry faster. Likewise, if you’re using a self-watering pot, switching to a regular pot will allow the soil to dry out.
When you have the choice, always go with a pot with drainage holes as drainage holes make it so much easier to care for your houseplants and keep them alive. Keep those beautiful drainage-less pots as cachepots.
You can learn more about hanging planters (and what to plant in them!) here.
You can learn about railing planters here.
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