A lot of people are nervous about repotting a plant, but you really needn't be! In fact, if you do it right, your plant will likely love you for it and delight you with new growth. Here's some straightforward answers to the questions I get asked the most, about repotting.
Why repotting is necessary
If you think about plants in their natural habitat, growing in the ground, they don't have restrictions to spreading their roots. Where possible, you want to be replicating the plants natural habitat. So if in their natural habitat they can spread their roots and grow with no restrictions, you will want to provide the same "ideal" conditions at home.
When to repot
There are a couple of signs that your plant needs repotting:
- It looks too big for the pot - a pot should be about 1/3 the size of a plant
- When you water it, the water is not absorbed quickly and it sits on top of the soil. This is because the roots have grown so large that there is little soil left in the pot to absorb the water
- Roots are growing out of the drainage holes - they're wanting to spread their wings!
- The plant stops throwing out new growth and growth seems to stall
Plants that you purchase that are in nursery pots, will require repotting a few months after you bring them home. Sure, you can keep them in the nursery pot for longer, but they're not likely to get much bigger and growth will be much slower due to the roots restrictions. Plants in nursery pots, also have a slow release fertiliser in them and this only lasts around 8-10 weeks.
You will often hear people say that you can only repot during spring and summer. You can actually repot at any time of the year, so long as the plant is not under stress and not a plant that goes into dormancy (such as Caladiums and Alocasia). The reason why it is recommended to only repot during spring and summer, is that this is when a plant is in it's active growth phase. If you're repotting during the growth phase, they're likely to "bounce back" quicker. In saying that, I have personally repotted during all seasons, with no issue whatsoever.
What soil to use when repotting?
There is so much confusion around this and even I was confused if I'm honest. So I went to a horticulturalist at the Christchurch Botanical Gardens, and asked them what soil is best for houseplants. I was surprised by his answer.
In his opinion, there is too much hype around indoor plant soil and I'd have to say that I agree. He said that the majority of houseplants, like a mixture which is 4 parts potting mix to 1 part perlite. Perlite is a natural substance that looks a little like little balls of polystyrene. It helps to aerate the soil and also absorbs water and releases it slowly. He said that there is no need to buy fancy houseplant potting mix and actually that many of these are no different to just plain old potting mix. These were the other soil types he recommended for other houseplants:
Cacti and Succulents - 1 part potting mix, 1 part pumice and 1 part perlite
Tropical plants (e.g Monstera) - 2 parts orchid mix, 2 parts potting mix and 1 part perlite
Ideally, you want to be replicating the plants natural environment as much as possible and healthy roots will equate to a healthy plant.
What size pot should you use to repot your plant?
This is an important aspect to repotting. If you go up too big, there is too much soil contained in the pot and when you water, this excess soil, will increase the risk of root rot. As a general rule, you want to be going up 1-2 inches in diameter from your current pot.
How to repot
You want to ensure that your plant is in a good state of health, or as good as it can be, before repotting. Repotting is disruptive for our plants, so we want to reduce that disruption and stress on the plant, as much as possible. I therefore recommend ensuring that the plant is well hydrated and I generally do this the night before I repot. Make sure the plant is due a watering and water thoroughly, the day prior to repotting.
You want to ensure that only healthy growth goes into the pot, so you want to remove any brown/dead or poorly leaves/growth. Only the good stuff should go into the new pot. If you keep poorly growth on the plant, the plant is working extra hard to revive this growth, rather than putting it's energy into growing new healthy roots and foliage.
Before removing your plant from it's existing pot, you will want to place some soil in the bottom of the new pot - at least an inch or two. You want the roots to be cushioned by the soil and not sitting directly on the bottom of the pot.
You then want to remove the plant from it's existing pot, as gently as possible. If it's in a nursery pot, you can lightly squeeze the pot, then tip it on it's side to ease it out slowly. If it's already in a cover pot, you want to use something like a blunt knife and slip it into the soil by the edge of the pot. This will allow you to slowly tease it out and tipping the pot and patting the bottom, will also help you with this.
Once you have the plant out of the existing pot, check that there isn't any further unhealthy growth that you need to remove. Then very gently, tease the ball of roots out, so you are loosening them from the ball they are in. This will help the plant to spread it's roots when it's in the new pot. You can lightly remove old soil but ensure that you are not putting huge resistance on the roots, so do this gently. You don't need to remove all soil, just the soil that comes away easily.
You then want to place the plant on top of the soil sitting in the new pot. You will want to ensure that the plant is not sitting too high, or low in the new pot. So the old top soil line of the plant, where it sat in the old pot, should be 1-2 inches below the top of this new pot. You will then want to hold the plant in the centre of the pot and place new soil around the sides and an inch or two on top. You can gently pat the soil down as you do this, but make sure that you are not pushing the soil down and compacting it too tightly. The roots like to have some air around them and pushing the soil down, will prevent this and harm your roots.
Last but not least, you will want to give your plant a good drink. You will then want to place it in a room where there are minimal stressors. What I mean by this, is not to place it near any heat sources (such as fires, heatpumps etc.) and ensuring that the room is not super hot or freezing cold - ideally a nice even temperature (between 12-23 degrees).
Voila! It's that easy. I really hope this has helped you to reduce any anxiety around repotting your plant. You are welcome to reach out to me anytime you have any questions and if I haven't answered a repotting question of yours in this blog, please do let me know and I will include it in here.
Happy repotting! Your plants will love you for it.