Basic Houseplant Care: Repotting Versus Potting Up


When it’s time to repot, should you increase the size of the pot? Photo: Hall’s Flower Shop and Garden Center

Repotting. Potting up. They’re the same thing, right?

Not quite. 

Repotting is a more generalized term. It means moving a plant to a new pot. There is no implication of pot size. 

Potting up specifically implies moving the plant into a larger pot. And that’s not always what you want to do.

Pot Size Is Linked to Growth

This young African violet may need to be repotted into a larger pot in only a few months, but once it reaches its full size, it will probably be happy in a 6-inch (15-cm) pot for the rest of its life. Photo: SueLee Charron

Potting up (moving a plant to a larger pot) tends to encourage it to grow faster and become larger. It’s the sort of thing you do to a younger plant, sometimes more than once a year. For example, you’d want to start a stem or leaf cutting in a small pot, but as the cutting grows into a plant, it will need more space, so you’d move it into a larger one, perhaps only a few months later. And likely a larger one again the following year. But as it attains the size you want, you reach a pot where giving it a larger pot is no longer worthwhile. 

Perhaps it has already reached its full size and will grow no further. That would be the case for an African violet or a cyclamen, for example, also many orchids. So, no need to pot up. But you’d still need to change the soil. So, you’d repot into a container of about the same size.

Once a houseplant has reached about the size you want, there is no reason to repot it into a bigger pot. Photo:

Another possibility is one you run into most often with larger houseplants, especially indoor trees. There is practically no limit to how large these will become, but there may be limits on how large you want them to grow. If your dieffenbachia or ficus is already as big as you’d ever want it to be, or nearly so, you wouldn’t want to repot it into a larger pot: that would just encourage it to become even bigger. Instead, you could repot into a pot of the same size and slow it down. 

I have plants that have been in the same size pot for more than twenty years. Two examples are a huge, bulky croton that I certainly don’t want to see grow any larger and a money tree (Pachira aquatica) that is nearly up to the ceiling. Yes, I could replant these giants into bigger pots, then prune them back when they go into a growth spurt, but why bother? Essentially, I’m underpotting them: repotting them into pots smaller than they would like, and that nearly stops their growth cold. Neither of these two plants has grown to any noticeable degree in twenty years. 

Essentially, underpotting is the equivalent of bonsaiing your plants: using pot size to keep their growth to a minimum, as bonsai masters do.

Repotting to Change the Soil

The main reason for repotting a young plant is to give its roots room to grow. But the main reason for repotting a more mature plant is to change the soil. 

You can see minerals salts building up on the side of the pot. Photo:

Over the years, mineral salts tend to build up in potting soil: minerals from tap or spring water, from fertilizer, etc. And as they do, they become toxic. When minerals in the soil around the roots are more concentrated than in the plant itself, water begins flowing out of the plant rather than in, leaving it in a constant state of drought stress. By unpotting the plant, then removing most of the old contaminated soil before repotting into fresh soil, you give the roots a new lease on life.

I find that I can get away with repotting small to medium-size plants (ones I don’t want to see grow, that is) every 2 to 3 years. Big ones in big pots can hold out for 4 to 5 years. Or you can try top-dressing and delay repotting even further. Read the article, If You Can’t Repot, Top-Dress for further information on that technique.

Clean Pot Needed

Clean the pot to remove mineral salt buildup … although cleaning inside the pot is more important than cleaning its outside.. Photo:

Do either thoroughly clean the pot before reusing it (minerals build up on the pot surface as well as in the soil) or, more logically, repot into a new or clean pot. (That way you can take your time and clean the old pot later.) And it can be a pot of exactly the same dimensions.

So, you decide. If you want your plant to grow, pot it up. If you want to limit its growth, yes, do remove the old soil, but repot into the same size pot, thus keeping it underpotted. Simple, isn’t it?

Repotting is best done in early spring, just as the plant begins a new growth cycle. And it can be carried on throughout the spring and summer if that’s more convenient. It’s best not to repot houseplants when their growth is at a standstill, usually from late fall through winter.

Top Dressing Houseplants


After spending several months in the winter doldrums, by early March (in the Northern Hemisphere at least), your houseplants are starting to come back to life. Buds form, new leaves unfurl, flowers appear. They are, in fact, reacting to the increase in sunlight, which is both more and more intense and of longer and longer duration.

This return to growth influences—or should influence—your way of caring for them. First, you can start fertilizing them again, something you probably stopped doing back in October. Also, tis the season to start thinking of taking cuttings, pruning, dividing and repotting, all best done when plants are growing actively.

The Annual Repot 

Yes, it’s the right season to repot your houseplants, but if you can’t… Photo:

Let’s talk specifically about repotting. 

Most indoor plants do best when repotted annually. They have increased in size over the last year and will appreciate a bit more space for their roots. For slow-growing plants, like most cacti and other succulents, plus orchids, repotting every two or three years will suffice. For young plants in small pots, though, repotting twice a year, in spring and again in early fall, may be necessary.

In addition to giving more space to plant roots, repotting into fresh potting mix solves a basic indoor gardening problem: it eliminates the mineral salts that have accumulated in the soil. Such salts are naturally present in water and are even more concentrated in fertilizer. In small quantities, most of these minerals are actually good for plants: they use them for their growth! Outdoors in most climates, any unused minerals are leached out of the soil by rain and so don’t accumulate. In pots, however, there is no outlet for minerals that start to build up, because excess water doesn’t drain away, carrying excess minerals with it, it evaporates. Thus, these minerals remain in the potting mix and start to accumulate, especially near the top of the rootball, sometimes forming a white or yellow crust on the side of the pot, on the plant’s stems of and on the surface of the mix.

Mineral salts build up on pot edges and even on the stem. Photo:

These surplus minerals slowly build up to toxic levels, damaging the roots near them and even killing stem cells. Repotting helps greatly to remove built-up minerals. But what can you do when repotting is impossible?

And there does come a point in the life of some plants when repotting into a larger pot is simply not feasible. They’ve grown to such a size that repotting is too much work. Can you even imagine repotting an indoor ficus tree in 20-inch (50 cm) pot … or even finding a larger pot? But then what are you to do then when mineral salts build up?

Top Dressing to the Rescue

One easy solution is top dressing. Mineral salts mainly accumulate in the top inch or so (3 cm) of growing mix, so you can remove the contaminated soil on the surface and replace it with fresh soil. Deeper down, the soil is usually still of decent quality. Top-dressing is not quite as good as repotting, but it comes pretty close!

How to do it? 

Just srape off the top layer of soil and replace with fresh potting mix. Photo:

You have to scrape off the top inch or so (about 3 cm) of soil. Whatever tool you want to use is fine: a hand cultivator, a trowel, a houseplant rake, etc. I just borrow a fork from the kitchen to do the job. Once you’ve removed the top layer of soil (put it in the compost bin: the minerals will give compost microbes a real boost!), all you have to do is to replace it with a fresh layer of potting soil. Finish up with a good watering and you’ve just given your plant a whole new lease on life!

Can you keep top dressing indefinitely? Logically, it would be wise to repot even a very big plant at least every five years. However, I have indoor trees that I haven’t repotted for 20 years and that are doing very well with just an annual top dressing.

Try top dressing to revive your tired houseplants. At least, if you just aren’t able to repot them. You’ll soon see a difference in their performance!

Fast and Easy Repotting



Need to repot? Learn how to do it the easy way! Source:

When repotting a plant, normally you would take the time to carefully inspect the roots, trim off a few dead ones, knock off a bit of old potting soil, etc. But sometimes you’re just too busy: you need to get that repotting done fast. Or maybe you’re repotting one of those plants that don’t like having their roots disturbed (clivias, amaryllis, hoyas, etc.). In both cases, there is a much easier method for repotting that leaves the rootball fully intact.

You’ll need a new pot 2 inches (5 cm ) larger than the original one, a second pot of exactly the same dimensions as the original one, some potting soil and a watering can.

Now, here’s what to do, step by step:


1. Pour potting mix into the bottom of the biggest pot and center the smaller one inside it, on top of the soil. Illustrations: Claire Tourigny, from book Les 1500 trucs du jardinier paresseux.


2. Now fill around the smaller pot and pack the mix down lightly.


3. Remove the smaller pot and you get… a perfect mold of the plant’s rootball!


4. Now remove the plant from its pot and slip it into the molded hole. Tamp the soil down a bit, water and presto: you’ve finished repotting!

Couldn’t be simpler!20180402E

Repotting Boot Camp


20180317A Conrad Nutschan, WC

This pot is nearly full of roots: definitely time to repot the plant! Source: Conrad Nutschan, Wikimedia Commons

Hey, it ain’t rocket science, but when you grow houseplants, you need to repot them from time to time. And if you’re going to repot, you might as well do it right! Here’s what to do!

When and How Often?

For most plants, an annual repotting is wise (see Why Repot Houseplants?), preferably in the spring, although summer and fall are also quite acceptable. Young plants that grow quickly (newly rooted cuttings, for example) may well need two repottings per year, moving them into larger pots each time. Plants that are mature and scarcely growing, such as indoor trees, as well as plants that grow very slowly, such as cacti and succulents, however, may stay in their pot for longer periods, up to 4–7 years some cases.

Getting Your Pots in a Row

Start by gathering the tools and products you’ll need. (There’s nothing more annoying than interrupting a repotting session to run off to the garden center in search of a missing item … unless it’s to run off to the garden center a second time just a few minutes later when you realize something else is missing!)

Here are some things you will need: pots, potting soil, a digging tool of some sort (a spoon borrowed from the kitchen will often do), a watering can, and a bucket or large bowl. And you may need the following: fertilizer, mycorrhizal fungi, horticultural charcoal, a sharp knife or pruning shears.

Most gardeners already have a ready supply of recycled pots: just clean one up thoroughly before reuse. Source:

You’ll need a pot one or two sizes larger than the original pot (that’s about 1–2 inches/2–5 cm) for small and medium-sized plants. For plants in large pots (12 inches/30 cm and up), consider a pot 3 or 4 inches (8–10 cm) larger. Remember any pot you use must have one or more drainage holes; if not, declare it officially not a pot, but a cachepot!

In general, tropical plants (African violets, spider plants, dracaenas, philodendrons, etc.) prefer a pot with impermeable sides, such as a plastic pot, as they dry out a bit more slowly. Cacti and succulents, on the other hand, do better in a pot that “breathes” such as terra cotta, as they actually prefer their growing mix to dry out more rapidly. That said, the material from which a is made a very minor detail. You can grow almost any plant in any pot (as long as it has a drainage hole, of course!).

Use the potting mix of your choice. Source:

Any packaged mix labeled as potting mix or potting soil will do. African violet potting soil is just standard potting soil with a fancier name. There are more aerated soil mixes for orchids and better-drained potting soil blends for cacti and succulents. Never use garden soil indoors: it may contain insects, disease spores and other unwanted hitchhikers and will almost certainly turn hard as rock after 2 or 3 waterings. I prefer soils that already contain mycorrhizae.

Off You Go

Prepare the soil first. Pour some into a bucket or bowl and add any ingredients you think are lacking. They can include:

  • Fertilizer: commercial potting soils usually already contain a 2- to 3-month supply of fertilizer; if not add the slow-release fertilizer of your choice to the potting mix. Never exceed the recommended dose of fertilizer, however: it will burn your plant’s roots and can even kill it. Remember: too much fertilizer is much worse than not enough!
  • Mycorrhizae: add them if your packaged soil doesn’t contain any. The vast majority of plants grow best when they are in contact with these beneficial fungi. Again, apply as recommended on the product label, but don’t worry if you add too much: it’s harmless to plant roots.
  • Horticultural Charcoal: an interesting addition if you expect the plant will be spending many years in its new pot (for example, a big plant you have no intention of ever repotting again!). Unlike other products added to potting soil to lighten it, like perlite and vermiculite, it doesn’t compact or condense over time (or at least, only very, very little), so it helps the mix maintain good structure for a longer time. Just add about 1/8 to 1/4 cup horticultural charcoal per 2 cups of mix.

Now add water to your soil mix. Yes, before you pot up. Modern soils are usually based on peat, coir, or bark, all products that repel water when very dry. So pour tepid water into the mix and stir it in with a spoon. The physical action of stirring miraculously makes the mix easy to moisten! Add enough water that the mix reaches a barely moist state. If you’ve gone too far and it is soaking wet, let the excess water drain out.


Knock part of the old mix off with a finger or stick. Source: Claire Tourigny, from the book Les 1500 Trucs du jardinier paresseux

Now, remove the plant from its pot (see How to Remove a Pot with Minimal Damage), and with a finger, spoon, pencil or chopstick, knock off about 1/3 of the old potting mix, going all around and underneath the root ball. Make especially sure to knock off some surface soil because it is usually the part most contaminated in mineral salts.


If there is a mass of roots at the bottom of the pot, just cut it off. Source:

If there is a mass of roots circling the bottom of the pot, slice them off with a knife or pruning shears. Just gather your courage and cut away! Those long roots were meant to anchor the plant in the ground in an outdoor setting; they are useless to a plant that grows in a pot and removing them will not harm the plant.

page 217 cutting roots

Cut off any encircling roots. Source: Houseplant for Dummies by Larry Hodgson

If there are roots entirely circling the root ball, cut them off too or they may come to strangle the plant over time.


Put a simple filter over the drainage hole: no need for gravel or pot shards. Photo:

Placing a so-called drainage layer of gravel or pot shards on the bottom of the pot is just a waste of time, effort and space. (See Gardening Myth: Houseplants Need a Drainage Layer.) However, you can place a piece of newsprint, paper towel, coffee filter, geotextile or mosquito net over the drainage holes and thus prevent the soil from washing out the first few times you water. Or don’t! If you don’t mind a few particles of soil dripping into your saucer, it isn’t worthwhile.


Don’t fill with potting mix right to the top: you need to leave as space into which you can fill with water when you’re rehydrating your plant. Source: Claire Tourigny, from the book Les 1500 Trucs du jardinier paresseux

Now pour enough of your pre-moistened potting mix into the bottom of the pot to raise the plant to the desired level. (The top of the root ball should be about level with the lower part of the pot’s rim.) Center the plant in the pot, then add potting soil around the root ball. Tamp lightly with your fingers. Finally, water well.

Most freshly potted plants can go right back to their original location. If the plant is growing in full sun, however, it would be wise to put it in a place a little less well illuminated for a few days, the time it takes to recover from transplanting shock.

That’s it: all it takes to successfully repot a houseplant. Get to it!

How to Remove a Pot With Minimal Root Damage

20180302A MAD gardening tips, YouTube.jpg
Before you can repot, you have to unpot. Source: MAD gardening tips, YouTube

The ideal time to repot your houseplants is when they start their growing season. That would be somewhere between late February and early May in the Northern Hemisphere. But before you can put a plant in a new pot, you first have to remove it from its original container.

Your goal is to get the plant out of its pot with as little root damage as possible. Grabbing the plant by the base and yanking it out of the pot is rarely a good technique. Half the time, you tear off a good portion of the roots. Here’s how to do it.

Water and Trim

First, water the plant thoroughly a day or so ahead. Think of the watering as a lubricant: it simply makes both roots and potting soil slightly more malleable and facilitates removal.

Next, if there are any roots coming out of the drainage holes, clip them off with pruning shears. Otherwise, they’ll hinder your unpotting efforts. Besides, you’re not sacrificing much, as those roots likely be damaged anyway during the repotting process.

Tip and Tap

Turn the pot upside down, carefully supporting the plant with one hand, then give it a hard tap against a table edge. Usually this will knock the root ball free. Ill.: &

Now, turn the pot upside down, and, holding the base of the plant between your fingers, bang the edge of the pot against a hard surface, like a table or desk, in such a way that the pot overhangs the edge of the surface and receives the blow, not the plant. Give it a fairly hard knock: you want the root ball to come loose. This is usually all it takes and you can simply slip the pot right off with no effort.

For plants that are too big and too heavy to turn upside down, place the plant on its side, hit the bottom of the pot with your hand to release the root ball, then pull the pot off.

Tough Times, Harsher Methods

Sometimes this doesn’t work and the plant still clings stubbornly to its pot. If so, and if the pot has flexible sides (the case with some plastic pots), try to compress the pot with your hand in two or three places, turning the pot so you free the root ball on all sides. Now try to remove the pot.

20180302C & .jpg
Running a knife around the inside of the pot will often free the root ball. Source:, and

If it’s still stuck, insert a knife between the pot and the root ball, then run it around the inside of the pot. This should free any roots that are stuck to the side of pot. Now try again to pull the pot off.

Sometimes you just have to sacrifice the pot in order to repot the plant. Such is gardening life! &

It still doesn’t work? There are situations where the pot simply will not come off. If so, more drastic actions will be needed. With a pair of metal shears (you could try pruning shears, but they’re not nearly as efficient), literally cut through the side of a plastic pot from the top to its base. Now pull it off. If the pot is clay or ceramic, take a hammer and smash it. Sure, you’ll destroy the pot… isn’t it better to sacrifice the pot than the plant?20180302B CT, 1500.jpg

When Repotting, Leave Room for Watering


20160329A.jpgYou may have noticed that conventional flowerpots, whether made of clay or plastic, always have a projection at the top of the pot (often called a shoulder or collar), but I’ll bet you didn’t know that this collar is not just a decoration, that it is actually designed to show how far to fill the pot with soil when you repot?

If you fill the pot with soil to its collar, but no further, when you water in the future, you can simply fill the empty space on top of the soil with water. It was designed to hold exactly the amount of water required to saturate the soil the pot contains, fully yet without overflowing… a neat little trick that can make watering much easier!

It’s Time to Repot your Houseplant When…


20160312A.JPGIt’s Time to Repot your Houseplant When…

…The plant begins to wilt only 2 or 3 days after you last watered it. That’s because its root system is so developed it has no more room to expand, plus the empty space between soil particles that normally serves as a water reservoir is now totally filled in. Think about it: if you repot your plant into a larger pot, you won’t have to water so often!

…The plant keeps tipping over. It’s become top heavy and will need more potting mix to hold it up. You might want to consider using a heavier mix (like cactus potting soil) or a heavier pot: clay and ceramic pots are heavier than most plastic ones.

…A whitish or yellowish crust has formed on the edges of the pot and the base of the plant. These are toxic mineral salts that build up over time in the soil of houseplants. By the time they are visible, they have started to kill the plant’s roots and may even be eating away at its crown. It’s best to repot and to remove as much of the contaminated old soil as possible.

…Lots of roots are wandering out of the drainage holes. This is a clear sign that the roots are looking for more space. Give them some!

…Root pressure has cracked the pot or even split it open. Idem.

…Spring has arrived! It’s simply a good idea to repot your houseplants regularly. Do so every spring for small to medium-sized plants and every two springs for large ones. Regular repotting helps maintain healthy growth and good bloom.

But I Can’t Repot My Plant!

Maybe it’s simply too big or unwieldy, making repotting difficult. If so, at least do an annual top-dressing. You’ll find all the details here.

If Your Tap Water is Hard…


20160228A.jpgIf your tap water is very hard, with a pH of 7.5 or higher (your municipality will be able to tell you), it would be wise repot your houseplants twice a year, in spring and early autumn, replacing almost all the potting mix each time. Hard water contains a lot of dissolved mineral salts, salts that are toxic to plant roots when they accumulate… which they will do very quickly in a pot where excess water doesn’t drain away, but remains in the saucer. By repotting twice a year and throwing the old potting mix into the compost, on the other hand, you’ll be cleaning the roots of contaminants, leading to much healthier growth from your plants.

If you can’t repot that often, consider leaching the mix every two months by letting water run through the soil and drain into the sink. Leaching likewise reduces the accumulation of mineral salts. You can find more information on leaching in the text Happy Houseplants Need Leaching.

Repot into Only a Slightly Bigger Pot



Plants tend to rot when planted into too large a pot.

In general, when you repot a plant, it’s into a larger pot. Normally you should choose a pot only one or two sizes (1” to 2”/2-5 cm) larger than the previous pot. Repotting into a much bigger pot (3 sizes larger than the previous pot or more) is an open invitation to rot. That’s because the roots won’t be able to fill the newly available growing space rapidly enough. The excess soil will then tend to stay moist and even waterlogged: a very conducive environment for harmful microbes to develop, including those that cause rot.

It is not, however, always necessary to repot into a larger pot when you repot a plant. A bigger pot stimulates the plant to grow to a larger size, but that’s not always what you want. Still, after a year or two, the old soil the plant has been growing in is probably becoming compact and overly rich in potentially toxic mineral salts. If so, simply unpot the plant, knock off much of the old soil mix as possible and repot into a clean pot the same size as the previous pot. Couldn’t be simpler!

When You Can’t Repot, Top-Dress


278.KWhen a houseplant remains too long in the same pot, the soil it grows in becomes contaminated with mineral salts. You can see them because they form a white or yellowish crust on the inside edge of the pot and even on the lower part of your plant’s stem. Theoretically you should repot a plant whose soil is contaminated, or at very least, leach the soil. But there are situations when repotting or leaching is difficult or impossible. For example, when the plant is in a pot so big that transplanting it or even moving it to the sink for leaching is going to be a major hassle. Or, when you have a climbing houseplant that is working its way up your indoor wall… or when the pot is permanently bolted to a floor or wall. Under these circumstances, what can you do to keep the plant in good condition?

Fortunately, there is a way to keep a plant in the same pot for 5, 7, 10 years or more: you just have to top-dress! This involves scratching the top 1 to 2 inches (2-4 cm) of growing mix and adding the harvested soil to your compost bin, then replacing it with a fresh layer of potting mix. This will help because toxic minerals tend to migrate upwards to the top of the pot: by replacing the contaminated portion of the soil with fresh mix, you will allow your plant to remain in good condition even if you don’t repot.

20150320CThe usual tool for top-dressing is a fork. Of course, I don’t mean a garden fork, but simply one borrowed from the kitchen. If you have one of those houseplant tool kits that people routinely give as a gift, but that no one every uses, the mini rake it contains would also work fine. Aren’t you glad you finally found a use for it!

When should you top-dress? Any season will do, but you will see results faster if you do it in early spring. That’s because your plant will be ready to begin its annual growth spurt at that time of year and a fresh coat of soil will signal it that it’s time to begin.

After your first top-dressing, mark it on your calendar for next year and make it an annual routine. After all, what wouldn’t you do to make your houseplants happy?