haworthia in a pot

How to repot a house plant (without killing it) 101

Really Caroline, a whole post on how to shift a plant into a slightly bigger one and stick a bit more soil in it?

Yes, actually, because there’s a bit more to it than that, should you be interested in not killing your plant babies.

Although, tbh, for many moons, I diligently moved all my plants from their nursery pots into ceramic, drainage hole-less pots as soon as I brought them home, filling in the sides of the pot with any old soil I could find.

And yeah, some plants’ll survive this.

But very few would thrive and grow and be beautiful and love you.

So, how should one repot a house plant?

I’m glad you asked.

Here’s my step-by-step quickie guide to repotting your plants:

  1. After you’ve bought your plant, wait at least a week to repot so that your plant is acclimatised. Repotting can be stressful. Some plants won’t need repotting for a considerable time, and will be happy to stay in their nursery pot.
  2. Ensure that you have a pot with a drainage hole to help prevent overwatering
  3. If you’re buying your potting mix, mix in some extra perlite for a well-draining mix
  4. Put a piece of coffee filter or a crock over the hole and add a layer of potting mix, enough  so that when the old pot sits on it the tops of the old and new pots are level
  5. Fill the gap between the old and new pot with potting mix
  6. Remove the old pot, leaving the perfect-sized hole for the plant.
  7. Take the plant out of the old pot and put it in the new one.
  8. Water it. Now leave it alone (keep an eye on it though) until it needs watering again.
  9. Voila!

That’s a pretty simplified method, but it’s easy for beginners. The only bit that’s liable to vary is whether or not you want to leave the old potting mix on the plant.

If the plant is relatively new and potted in a decent mix I leave the soil in. If it’s overwatered and waterlogged I remove the old soil, in which case I don’t use the old pot as a mould – I just fill the pot with mix and dig a hole for the root ball.

So, let’s get onto the nitty gritty:

What type of pot should I repot my plant into?

I only use two types of pots: plastic or terracotta. I do want to scout around for some ceramic pots, but it’s a bit harder to come by ones with drainage holes.

If you have a pretty pot that you want to use but it doesn’t have drainage holes in it, just use it as a cover pot and use it to hide a plastic pot. I would recommend using a pot a couple of sizes smaller though, just to make taking the pot in and out to water it a bit easier.

Terracotta pots: pros

  • Cheap – you can get cheap small ones for less than a pound, and it’s only a couple of quid for larger ones.
  • Porous – the porous nature of terracotta means that air and water can pass through the clay. This is great for any of you that are liable to overwater your plants.
  • Aesthetically pleasing – especially if you’re after that natural look

Terracotta pots: cons

  • Fragile – beware if you order them online. I have bought terracotta online before – I bought ten large pots for £18 and noy one broke, which I used as crocks to cover the drainage holes of the remaining nine. The only thing putting me off buying them again was the packaging – even though it was packaged in recycled and recyclable materials, the boxes were HUGE and I have no space for them.
  • Porous – great for plants that like to dry out but not so great for ferns and calathea that like to stay moist. That being said, I have a Boston fern and a Calathea Leopardina in terracotta and both are thriving.
  • Also, beware of potting plants with delicate roots in terracotta because the roots can stick to the porous clay – hoya are known for doing this but again, it’s not the end of the world if you pot hoya in terracotta – you can soak the pot to unstick the roots.
  • Water damage – again, due to the porous nature of terracotta water can leak through the clay and damage your furniture. You can buy varnished terracotta surfaces to stop them leaking but they’re more expensive and harder to find. I use ceramic dishes or saucers instead – you can often find them in charity shops and Wilko do cheap ones.

Ceramic pots: pros

  • Non-porous – so water can’t leak through and damage your surfaces. You won’t have to water any moisture-loving plants as often as you would if they were in terracotta
  • Variety – you can get ceramic pots in all shapes, sizes, colours, and patterns

Ceramic pots: cons

  • Drainage holes – it’s more difficult to come by ceramic pots that come with drainage holes and they can be delicate, so it’ not easy to drill holes in them.
  • If you’re prone to overwatering your plants may suffer, since water can’t evaporate out of the walls of the pot
  • Similarly, air can’t get through the clay, so your roots may end up rotting due to lack of air flow.

Plastic pots: pros 

  • Cheap – free with the plant you buy! Even the huge ones are pretty cheap
  • They often have multiple drainage holes and you can easily add more
  • A few options in terms of colour and style
  • Non-porous, so the delicate roots of plants won’t stick so easily to the sides

Plastic pots: cons

  • Bad for the environment and provisions for recycling is not great for them yet. However, you can use them many times before they break. Avoid black if possible, since it’s hardest to recycle, and ask your local garden centres if they have a recycling scheme.
  • Not great aesthetically, but obvs this is massively a matter of opinion, and there are tonnes of great hacks on Pinterest to make them a bit prettier.
  • Non-porous, so serial overwaterers need to be aware that the pot won’t wick much moisture away through the plastic.

What potting mix to use when repotting your plants

Although actually, first we’ll discuss what not to use.

Don’t use:

  • Pure compost
  • Multi-purpose outdoor potting mix
  • Dirt you’ve dug up from the garden

At least, unless you can absolutely help it. If you have to use compost or general potting mix, at least mix it with something gritty or some perlite. Though if you’d go to the trouble of mixing in perlite I can’t see why you wouldn’t grab the right stuff in the first place, but anyhoo.

Don’t use soil you’ve found in the garden. If you HAVE to (again, I can’t see why you’d have to) make sure to bake it in the oven first (on a low heat for an hour or so) to kill all the bugs that are living in it.

If the reason you’re not buying proper house plant potting mix is budgetary, then it’s in the best interests of your plant not to repot.

If it’s rootbound, you’d be more likely to save your plant if you trim the roots. Root trimming is NOT recommended, but your plant is more likely to recover than it would be if it were potted in too heavy a potting mix.

Ok, so what should you use?

General house plant potting mix

I use at least a bit of general house plant potting mix in almost all of my plants, excepting plants that I’ve purchased a specific mix for.

That being said, general house plant soil is almost always a bit too heavy, so I like to mix in some perlite and bark – I tend to use a ratio of two parts potting mix, one part bark, and one part perlite.

Plant-specific potting mixes

The ones I use are orchid mix (for orchids, wouldn’t ya know?), carnivorous plant mix (for, you know), and cacti and bonsai mix.

If you don’t want to buy separate bags of perlite, bark, and general house plant mix then I’d just use cactus mix, because it’s really well-draining.

This would be the case if you only had a couple of plants. If you have a large collection, it’ll work out waaaay cheaper in the long run to buy bark, perlite, and houseplant potting mix.

The reason I use a specific orchid mix is that it’s basically just bark with some fertiliser as an additive. If you have a separate orchid feed, then just use pure bark (which is pretty cheap either online or from reptile-selling pet shops) and make sure to add the feed when you water/soak it.

If you want to keep your carnivorous plants happy, then I’d recommend buying the specific soil mix when it comes to repotting. Carnivorous plants tend to be bog plants, so they need a heavy mix in order to stay as moist as they need. Be careful when repotting because they really don’t like being touched.

Making your own repotting mix

I’d recommend watching this Kaylee Ellen video – it contains her personal aroid mix. A lot of popular house plants are aroids (philodendron, monstera, pothos) and the mix is also good for most houseplants that like a good, well-draining potting mix.

For the recipe you’ll need:

  • Coir
  • Bark
  • Worm castings
  • Activated carbon
  • Perlite
  • Sphagnum moss

I like to stick to my half potting mix, half homemade mix because I’m too poor currently to buy activated carbon in any quantity. Also I can’t be arsed. Which is the most pressing reason.

When to repot your house plants

It’s fairly easy to tell when your house plants need repotting, which is great news if you don’t want to repot – buy plants that show no signs of needing repotting.

When the roots are coming through the bottom of the pot

This is fairly self-explanatory, yes? When the roots start poking out through the drainage holes, then it’ time to repot. That being said, I don’t repot immediately as soon as I see roots emerging. It’s good practice to turn the pot on its side and GENTLY ease the plant out.

A root-bound plant will have roots encircling the inside of the pot. If you see no roots then your plant could be ok for another couple of months.

When you have your plant’s root exposed, check that they’re looking healthy and plump and white – any signs of black, squishy, rotten roots need to be dealt with – often by having a little chat with yourself about overwatering.

When the roots are coming over the top of the soil

This is a more sure sign that your plant needs repotting, but it’s worth a look at what’s going on below the surface anyway. I have a curly spider plant that always seems to have a roots growing over the top – even when I gave it a suuuper deep pot.

Also, some plants just…grow roots above the surface of the soil. We know that a lot of plants such as philodendron grow aerial roots, but they’re not always the same as ‘regular’ roots.

(Aerial roots tend to be used to climb trees as well as absorb moisture.)

Orchids, for example, are epiphytes (meaning that they grow on plants and get their sustenance from around them, rather than from the ground. They’re not bothered about keeping their roots in the pot AT ALL.

I mean, look at them:

roots on an orchid

I’m sorry, they look pretty gross, like little worms, but it’s exciting, because this orchid was overwatered as hell and potted in normal potting mix. Now it has a whole new medium and a sexy clear pot.

So yeah, roots poking over the top of the soil is another sign that your plant needs to be repotted.

Your plant is excessively thirsty

If the root system of your plant is growing, it’ll displace the soil in the pot. If there is less soil in the pot, then the pot can hold less water whilst at the same time the large system is taking up lots of water. See? That’ll mean a very thirsty plant.

Plant growth has slowed

At a certain point, the roots won’t be able to grow anymore, so they won’t be able to support any more growth. If your plant is only a juvenile, this could lead to a stunted plant and maybe probably even death.

Don’t worry too much about this stuff. If you keep a regular eye on your plants – checking the bottom for protruding roots etc, you’ll be able to repot in plenty of time. Your plant won’t become rootbound overnight.

If you start to notice a couple of roots poking through, now’s the time to get your repotting stuff together – get yourself some perlite and potting mix at the very least, and a new pot.

What size pot should you use to repot your house plant?

It can seem time saving to repot your plant into the biggest pot you can find, but plz plz don’t, for a couple of reasons:

  • You can send your plant into shock. 

Repotting is stressful to your plant anyway. GIving it a vast space in which to live will not help at all, and could even kill your plant.

  • You run the risk of overwatering.

Not many plants like living in wet soil, and the more soil you have (i.e. the bigger the pot) the more water that soil can hold. With only a small root system with which to soak up the water, the soil remains wet for much longer, increasing the risk of root rot.

If you have a big pot that you specifically want to use, then consider planting more than one plant in there. If you have a couple of philodendrons or pothos, then you could end up with a much fuller and bushier looking plant – you could even mix a couple of different types together, though be sure that they’re of a similar size and have similar requirements with regards to light and water requirements.

In general you’ll only want to increase your pot size by an inch or two.

The dos & don’ts of repotting

  • DO be gentle.

Repotting is stressful to your plant at the best of times. You chucking it about won’t help at all.

  • DON’T just use any soil you have lying around

Take the time to research your plant’s needs with regards to drainage. It’ll save you money (on new plants) in the long run

  • DON’T reuse soil

It could be harbouring pests and diseases. If you don’t like the wastage and can’t compost it, then you can bake it in the oven to remove nasties.

  • DO wear gloves

You think it’s a two minute job, so why bother? Because you’ll be scrubbing your nails for months.

  • DO wait until a few plants need repotting

You might be able to save on pots by just buying one big pot and moving everyone up a size. Then you have a free pot! Go and buy another little plant!

Wrap it up, Caroline

Ok, I hoped that helped answer your questions about repotting your plants. Feel free to leave any questions in the comments, and I’ll try my best to google it answer.

Ironically enough I’m writing this post to procrastinate. I have a few plants that need repotting – I had a rather large plant haul over the weekend.

Oops.

Although I managed to pick up a philodendron Florida Beauty (I think) that was mislabelled as a Syngonium Red Arrow (?? – google it – it looks nothing like what I bought), a cheap-ass Calthea Orbifolia and a load of other Calathea. On the hunt for some nice cover pots though, because Calathea are not terracotta fans (though my Leopardina is in terracotta and is my star in terms of being easy to care for.

Oh, and if you’re worried about my humidity levels for my new-found Calathea friends, I also invested in a hygrometer that shows my kitchen humidity being…65%. Yesss.

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