You’ve worked out that your plant has outgrown its pot, but how to go about repotting it without damaging the plant and to give it the best chance of thriving? Here are the steps I always take, and once you’ve done it a few times, you’ll realise just how simple it is. Make it easier for yourself by clearing space on a work surface and getting out all of your equipment before you start. It also makes sense to check all your plants and repot any that require it in the one session. Your plants will thank you for it and repay you with new growth and good health.

It’s important to repot during a growth phase, when the plant will be able to re-establish itself. Early spring is the perfect time, though you can repot up until early autumn if need be.

Gently squeeze the plastic pot to loosen the soil and roots
If your plant is in terracotta or another firm pot, you may need to run a butter knife around the inside edge; you can also push a blunt object into the drainage hole to dislodge the root ball. Extremely pot-bound plants might need heavy duty intervention – sometimes you have no alternative but to crack open a clay pot or cut a plastic one to remove the plant.

Once the plant is loose, hold the base of the trunk, stems or branches and slowly lift the plant out of the pot
I always feel around the plant first to gauge how delicate it is and the best place to hold it to avoid damaging it. Don’t be hard on yourself if a few leaves or stems break off. While some plants are tough as old leather, others are very fragile. After you’ve repotted a few different types you will start to feel more confident with this. If a plant is very root bound, lie the loosened pot on its side and gently shake or massage the pot with one hand while easing the plant out with the other.

Carefully loosen the roots so that the soil falls away
Try not to break off too many roots, although sometimes this is unavoidable. If the roots are very tightly wound, you will need to be a bit firmer. Use a chopstick or the handle of a teaspoon to gently tease out the outer roots so that when they go into the new pot, they will grow more quickly outward into the fresh soil. I give the plant a light shake at this stage to remove any loose mix and roots. This is also a great time to inspect the roots: healthy roots are generally firm and pale in colour with pale, active-growing tips, although some plants can have roots of a different colour (such as reddish or dark brown). Dark, mushy roots are generally a sign of rot, while dry, brown roots that have no moisture inside when cut are dead. Both of these should be removed with secateurs.

The plant is now ready to go into its new pot
If the plant is healthy and there are lots of roots in the pot, a larger pot will be of benefit and encourage new growth. If the pot is only half full of roots and a lot of soil falls out when you remove it, it’s better to use a pot of the same size as the one the plant came out of, and you will simply replace the old soil with fresh. Some plants like snug roots, while others like lots of soil to grow into. As a general rule, I usually pot up to the next size nursery pot, unless I know a particular plant is a fast grower.

Place some potting mix in the new pot
Use enough so that when you hold the plant in the centre of the pot the base is a couple of centimetres below the rim and the roots are touching the mix in the bottom. The ideal position for a plant to sit is with the roots covered but the trunk, stem or stems above the soil line. Generally, the position a plant is in when you buy it from the nursery is about right, so try to aim for that. If you have a pot with large drainage holes from which soil is escaping, coffee filters make a great barrier, keeping the soil in the pot but allowing water to drain through. Just place them over the holes before adding mix to the pot.

Fill around the roots with potting mix
Keep filling until the mix reaches the desired level, then grab the pot with both hands and firmly tap it a few times on the surface. If there are areas where the soil has sunk, add more mix and then tap again. Don’t press the soil down because this can remove pockets of air that are good for the roots.

Sprinkle over controlled-release fertiliser pellets
These little spheres control the amount of nutrients that your plant receives depending on the temperature and moisture levels. Some people mix them into the soil but I prefer using them as a top dressing so I don’t forget that I’ve applied it – I can see how old they are and know when to reapply.

Finally, give the plant a good drink
Water the pot until water runs out of the drainage holes. Then drain it well before moving it to its new home. I use a half-strength seaweed solution to water in my newly potted plants. It gives them a boost during a time of stress. Simply use a watering can to apply the seaweed solution generously to the soil and leaves.

These tips are extracted with permission from Green Thumb by Craig Miller-Randle ($44.99), published by Plum. Photography by Mark Roper and Craig Miller-Randle.