To keep potted plants healthy and thriving, they need to be repotted regularly. This means taking them out of their container and either putting them into a new, larger container, or simply replanting them into the same container with fresh potting mix. Repotting is done to provide extra growing space and nutrients.


How often to repot

The frequency of repotting varies with the growth rate of the plant and size of the pot. The most important thing here is to repot only when your plant needs it - we recommend no more than once a year for small, fast-growing plants, while larger plants growing in a roomy pot may only need to be repotted every two to three years. Mature, healthy plants that are making little new root or shoot growth and are growing in good quality potting mix may need repotting at less frequent intervals.

Repotting can be done at any time of year and should be done urgently if the plant is struggling to survive because it has outgrown its container. If there’s no urgency, autumn and spring are good times to repot most plants. Always place repotted plants into a sheltered spot (protected from cold or heat) until the plant has settled into its new potting mix.


Signs you need to repot

Indications that a plant needs repotting include:

  • The potting mix is drying out frequently, or the plant is visibly wilting - this happens because the soil has lost its water-holding capacity over time, or there may not be enough potting mix left in the pot
  • The potting mix is difficult to water - you might notice that when you do water, instead of soaking into the mix it pools on top or runs down the side of the pot
  • Your plant is too top-heavy for the pot and has begun to blow over - a plant in a too-small pot will often become unstable
  • You notice roots protruding from the drainage holes or your pot has developed cracks
  • You notice increased pest or disease activity - this is often due to water or nutrient stress
  • Your plant is failing to thrive or developing yellowed foliage - this is usually due to depletion of nutrients in the potting mix
  • Your potting mix is slumping – that is, the level of the potting mix has dropped within the pot indicating your plant has used up a great deal of it.

Potted plants should also be repotted into fresh potting mix when there are concerns that the pot contains pests (such as curl grubs or ants). Follow the same steps as you would to repot any other plant, but wash all infected potting mix away from the root ball and clean the pot thoroughly before replanting. If you're not repotting because of a pest infestation, you should skip this step to avoid too much root disturbance.


Choosing a potting mix

Repotting fiddle leaf figWhen repotting, use a good quality potting mix that meets the Australian Standard for potting mix (AS 3743). A potting mix that meets the Standard will carry a series of ticks on its packaging and be either regular (black ticks) or premium (red ticks). Premium potting mix contains slow-release fertiliser to sustain the potted plant for three months without additional fertiliser.

As well as selecting a good quality potting mix, also choose a mix that has been formulated for the type of plant you are growing. Specialised mixes exist for a range of plant types, including indoor plants; plants growing in terracotta or hanging baskets; native plants; roses; gardenias, azaleas and camellias; cactus and succulents; bonsai; and orchids. These specialised mixes may vary in particle size, nutrients, pH and water-holding capacity.


Difficult to move and rootbound plants

When repotting, gently remove the plant from its old container. If the pot is narrower at the top than the base, it may be necessary to cut or break the pot to release the plant. Tapping the sides of the container and turning it on its side can help to release the root ball and make it easier to remove the plant from the old pot. Never tug on the stem to try to get a plant out of a pot, as this can make the stem break away from the root ball.

Check that drainage holes are clear before starting to remove a plant from its pot, as the roots may have grown through the drainage holes and even into the ground. To release these roots it may be necessary to break the pot. Dig up as much of the root ball as possible to repot.

Examine the root ball. It there is little potting mix left and the roots are congested, matted or circling so that they retain the shape of the container, the plant is root bound and well overdue for repotting. In this situation it is necessary to gently prune the matted or circling roots. Also trim any roots that were broken or damaged when the plant was removed from its pot. If a plant is being returned to the same pot, but with fresh potting mix, it will probably be necessary to trim the roots prior to repotting. Remove any weeds or pests. A root-bound root ball will benefit from being soaked in a bucket of water with a seaweed tonic before it is repotted.

If it is very hard to repot a plant, removing some of the potting mix and replacing it with fresh mix from time to time, along with adding well-rotted manure or compost to the top of the pot, can help prolong the time before repotting becomes vital.


Extra repotting tips

Ideally select a new pot that’s slightly bigger than the old pot with plenty of space for the root ball. Ensure the new pot has plenty of drainage holes in its base. To prevent potting mix leaking through the drainage holes, you can cover them with a piece of mesh laid across the hole inside the pot. It is not necessary to place crocks (broken pots) or pebbles in the base of pots.

If the pot is very large and heavy, put it into position before starting to fill the pot with potting mix.

Partially fill the pot with potting mix, place the plant into the pot so it is centred, upright and around 2-3cm below the top of the pot. Fill around the root ball with more potting mix, watering and firming to avoid any air spaces around the roots. Water the plant well.