When, how, and why repot a plant ?
You read on my care sheets to repot your plants every 2-3 years. I explain here when, how and why.
When ?
We repot our plants in slightly larger pots, 3 to 7cm more, as soon as the roots protrude above or below. I gave you an example in the main photo: normally you have to repot before it gets to that point! You should know that repotting is always a stressful time for our plants. Some small roots are often pulled out during the process. This is why it is advisable to favor repotting during the spring or the summer, from April to August, during the growth period of the plant, because this will allow it to quickly redo its roots.
How ? The ideal is to make sure to damage as few roots as possible: knowing that not damaging any at all is impossible. The first thing to do is to water your plant a little if the soil is too dry. If your plant is in a plastic pot, you often have to see videos of gardeners cutting the pot with scissors: personally I think it's really wasteful. An empty pot can always be used later, for repotting a smaller plant. So I advise you instead to press on the sides of the pot, to gradually bring the plant out horizontally:
If your plant is in a terracotta pot, you must dip one of your hands to the very bottom of the pot and gently push the plant and its roots upwards. It's a little trickier than with a plastic pot.
Then, you must delicately untie the roots together; this will allow the plant to continue growing from untangled roots. Also, this allows when the potting soil was old, to remove as much of the old soil as possible:
Sometimes when you repot an Alocasia you will find bulbs, which you can either leave attached to the parent plant or plant in another pot while waiting for them to germinate.
Here, I am repotting a Calathea and I find this in the potting soil: be careful, it is not a bulb! This is a water reserve, common among the Calathea. You should definitely not remove them! It's not a big deal if you pull one out accidentally, but be careful all the same, they help the plant if you forget to water.
Finally, make your substrate mixture: I simply mixed potting soil with perlite, and I added the old soil that my plant already had, because it was not too old. It's a Calathea Lancifolia, probably one of the least demanding Calatheas, so I can afford it. For the most difficult ones, like Warscewiczii for example, the best substrate for Calathea remains the intermediate aroid.
I put my Calathea back in a plastic pot, as they retain more moisture than terracotta pots, and my Calathea prefers that. I would have put a terracotta pot for a Hoya for example, because they need the substrate to dry more quickly.
Finally, you can put the plant in its new pot: don't forget to pack the soil well (not too much either, otherwise it can suffocate the roots), just enough so that the plant stands upright.
And there you go ! Now you have to clean up all the dirt that has fallen next to it. Then all you have to do is water your plant a little to seal everything.
Why ?
We repot our plants for two main reasons:
1- the first, the pot is too small, and the plant needs more space to continue growing. This is visible when the roots come out of the pot, and this was the case with my Calathea.
2- The second, the potting soil is too old and the plant has exhausted all the nutrients present in it. It must be changed to provide it with the nutrients necessary for its growth. And don't think that adding fertilizer would be enough: old potting soil is too damaged to allow the plant to drink properly, and liquid fertilizer could burn its roots. Potting soil becomes too old after 2-3 years.
But also for other reasons:
Sometimes, repotting is necessary in the event of an attack by pests: if you are facing an invasion of thrips for example. Or even an invasion of sciarids and you do not want to try nematodes.
There is a final scenario: you can repot a plant when you realize upon purchase that its substrate is not suitable for it. However, it is always wiser to wait ten days before repotting a new arrival, to avoid double stress.
An alternative to repotting
When your plant has become too large and you cannot repot it because it is too heavy, or if you do not want a plant to become larger by giving it a larger pot, you can carry out what is commonly called surfacing: this involves removing as much soil as possible from above, without removing the pot, and replacing this soil with new potting soil.
To know
Sometimes garden centers sell plants in seedling pots, which are tiny and put directly into larger pots. This suffocates the roots and makes repotting very complicated because they absolutely have to be removed. Fortunately they are still plastic, so you can cut them without regrets to free the roots.
Here is an example when repotting my Syngonium Red Arrow
