Repotting houseplants: is it really necessary? How to know when to do it?
Calling to all houseplant experts,
I've had my plants for a couple of years, and they seem happy and growing well. I currently have a flamingo flower and a philodendron (here is a picture of them).
Over the years, I think I have gotten pretty good at taking care of them. One thing that still remains a mystery, though, is repotting and when to do it. I have never done it before, and info online seems confusing and often conflicting.
I live in a small space, so I would prefer not to have to do it, but I can see roots growing out of the bottom of the vases, and the plants are getting rather big: so much so, that my philodendron needs external support to not fall down. Nevertheless, they both keep growing.
So, onto the questions: how does one know when it is necessary to repot a plant to a bigger pot? What happens if I do not do it? And if I must do it, how should it be done? Ideally with minimal resources, since I am very limited on storage space...
And since we're at it: any houseplant-related pro-tips from the veterans?
A good rule of thumb is to start considering repotting when you water it and the water comes out into the drip tray almost immediately. That's usually indicative of roots taking up most of the cation capacity of the soil, meaning it isn't retaining water and nutrients very well.
As long as you water and fertilize as needed (which will become more and more frequently), probably nothing much.
In fact, this is a lot of what happens with bonsai trees: they are typically potted in a soil with very low organic matter so it retains very little water/nutrients, and they need to be watered frequently (daily, for many trees in some seasons/climates).
One downside is that it could end up strangling itself with its roots as they wrap around the outside of the pot. But girdling is a lot more common in trees that were kept in a too small container for too long and were planted too deeply, causing the roots to wrap around the trunk and then slowly cut off its own nutrient transfer between the leaves and roots.
The easiest way is to "slip-pot": you pull the plant and root ball out from the pot whole, then put some new soil in the bottom of a larger pot, place the plant and root ball in the new pot, then fill the rest of the space in with new soil. It's easier to do before watering, when the soil and roots are dry because they'll slide out more easily. Pick a pot that only adds an extra inch or two around the sides compared to the original pot.
Alternatively, once you have removed the plant and roots ball, you can use your fingers to loosen up roots where they were wrapping around the old pot to free them up to grow into the new soil more easily.
You don't have to be super delicate or gentle; you will definitely end up tearing/breaking some of the roots, but as long as you're not disturbing the core ~50% of the root ball, it will be fine.
I had a bamboo orchid in the same fairly small pot for 10 straight years. After a while it just stopped getting bigger. I eventually repotted it when I had more space to keep it in and it exploded.
Not literally. But it's doing very well now.
Perfect timing for this post as my weekend plans looked to involve repotting and I've never been very sure I'm doing the right thing when I do it. For the" only adding an extra inch or two around the pot" is there a downside to going bigger? I feel like my plants need repotting every spring and having extra growing room might postpone that to two years?
If it's too deep, it will be difficult for all of the soil at the very bottom to dry out. If the soil stays wet for too long, you can end up with bacterial/mold growth and it also leads to poor oxygenation.
In short, the
wet --> dry --> wetcycle is important for potted plant root and soil health, and it's difficult to get that cycle to occur uniformly (at least without stressing the plant) in a pot that's too big.But Seag doesn't want the pot to be bigger, though. Is there a way to keep the plant small and healthy?
This gets back into bonsai territory. Plants don't really want to find an equilibrium; they want to keep growing.
In bonsai, you typically have to trim foliage, repot (typically reusing the same size pot or even a smaller one), and trim the roots back to prevent it from getting too root-bound every year. (For bonsai species, this has an added bonus effect of causing new leaves to come in smaller and new roots to come in more fine.)
So, if you wanted to stay in the same size pot (or even size down), you could apply the same concepts by trimming the roots back an inch or two during repotting—and even going down a size—and trimming back the top growth to keep it the desired size.
Some species of plants will respond differently to being trimmed, though, so I'd definitely make sure to look up the best way to do it for any specific species to make sure it will have the desired effect.
I don’t have experience with those particular plants.
About repotting in general, though, there are a few reason
2. The soil in a pot becomes compacted over time, even if you include things like bark and moss in the mix. This makes it hard for the plant to grow new roots.
3. It gives you a chance to check the health of the roots. The earlier you find root issues, the easier it is to address them.
4. If you want a bigger plant and it isn’t the kind that likes to be pot bound, you put it in a (slightly) bigger pot.
5. If you want to divide a plant, you’re going to remove it from the pot anyway, so might as well freshen up the soil.
As /u/smithsonian mentioned, though, you don’t have to repot. I used to never do it and had a couple of
plants that lived many years. This was before I started gardening and looking into how plants interact with soil (or in the case of my holiday cacti, their soilless growth medium). I never had a holiday cactus bloom until I started repotting them every couple of years and feeding them orchid food, now I get 2-3 flushes a year.
As to when, the app I use for watering reminders tells me when to do it. Some plants get stressed if you repot them at the wrong time of year, it’s worth checking for each variety.
I was really nervous the first couple of times I repotted a plant. It went fine, even with my lack of experience. My main tips are to set up outside or in a place that’s easy to sweep up, and to be patient and as gentle as you can. Sometimes it’s hard to get the plant out of its pot, it happens. A butter knife may help.
Is the app a plant specific reminder app and if so what is it/would you recommend it?
Not the person you replied to, but I've used an app called Planta for plant-specific reminders and it's really solid. Afaik only some of the reminders are available on the free version, but the most vital reminder (watering) is available for free and if you're into plants enough, I think it's worth the subscription price. I know repotting suggestions are a thing in the paid version, but not sure if they're in the free version. The app also includes a lot of educational info about how to perform certain tasks and assess certain things about your plants, which I think is mostly available for free.
Granted, I've killed plenty of plants still, but that's had more to do with me ignoring the reminders than anything else. I've recommended it to family members with houseplants to great success, even just the free version.
Yes, that's the one I use as well.
Depending on the plant, you can sometimes divide it and get two (or multiple) plants for the price of one.
With plants whose roots form rhizomes (asparagus fern, ZZ plant, calathea, some others), you can gently divide the rhizomes and attached stems into smaller clumps (not smaller than 3 - 4" bundles) and give each clump its own pot. Your flamingo flower (Anthurium) forms rhizomes, and instructions for dividing it can be found here.
I originally thought you had a vining philodendron, but the picture shows a tree type. It's riskier to divide those and you're best off just repotting it as it grows until you run out of space.