How to… repot a houseplant

by Rhiannon James

Photo by Joe Lee

If you’ve got indoor plants that are permanent residents in your home, then at some point, you’ll need to pot them on. Moving a plant into a bigger pot gives its roots (and therefore the plant) more space to grow and to absorb the water and nutrients it needs to survive. Luckily, it’s a straightforward job and it only takes ten minutes or so to do.

The best time to pot on is in spring so the roots have plenty of time to become established during the growing season. You’ll find that you’ll need to pot on younger plants more often than more mature ones, perhaps as often as once a year, because they’re growing more quickly. But, bear in mind that some plants, such as most Bromeliads rarely need repotting.

It’s easy to check if it’s time to pot on. Look if the roots are sticking out of the bottom of the pot and then, take out the plant, and see if they’ve grown into a thick mat which is mostly covering the compost. There may be other signs too – the plant might be growing slowly or not at all, even though you’ve fed it, or it might be drying out very quickly. If this is happening, then your plant needs a more spacious home so follow the steps below.

1. Choose a pot which is only slightly larger than the original one and ideally, the next size up (usually 2cm bigger in diameter). If you use one that’s too big, the compost will become too wet when you water the plant because the roots aren’t large enough to absorb all the moisture. This will eventually damage the plant. If the pot has been used before, you will need to wash it thoroughly with soapy water and then rinse it before you start. If you think it might have housed any pests or diseases, give it an extra-deep clean with Milton sterilising fluid (which is normally used for cleaning babies’ bottles).

2. Make sure the pot you’re using has drainage. If there are no holes in the base of your pot, you will need to drill them yourself. Space them out evenly across the base of the pot.

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3. Water the plant and allow the excess to drain.

4. If you like, you can put some grit in the base of the pot to increase drainage. Make sure though, that you only use horticultural grade grit.

5. Then put some compost into the pot. It’s best to use specialist house plant compost but general purpose compost mixed with a little John Innes will also work. Bear in mind that some house plants such as succulents, require their own specific type of compost. Start by firming some compost into the edges of the pot and then fill in until the compost’s at a point where the plant will be sitting at the right level (just below the top edge of the pot to leave a bit of room for watering). You can sit the plant into the new pot to check.

6. Then remove any dead or damaged foliage from the plant to prevent fungal infections and other diseases spreading. You can either pinch leaves off with your fingers or cut them away with scissors or secateurs. Try to take them off at the base without damaging the stem.

7. Remove the plant from the pot by covering the top of the pot (and holding the plant) with one hand whilst gently squeezing the sides with the other. The plant should then slide out.

8. Remove some of the compost from around the top of the roots so you can make sure that the plant will be at the same depth as in the previous pot.

9. Carefully tease out some of the roots so they are encouraged to grow outwards into the new compost.

10. Put the plant into the new pot, check the depth and then fill in around the edges with the compost. Try and make sure any gaps are filled and the compost is reasonably firmed in, without being squashed, because it will settle when you water it. Also try to make sure the compost doesn’t rise towards the edges of the pot or you’ll create a pond in the middle.

11. Water the plant carefully with tepid water and then you’re done! Put the plant in moderate light for a week or two and then move it back to its permanent position. Remember to check the compost instructions to work out when you’ll need to start feeding again.

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