Guide written by:
John, DIYer & IT developer, Brighton
When a plant outgrows its pot, you will have to move it into a larger container. This is also a great opportunity to renew your potting soil and, ideally, add a drainage layer to your pot. In turn, this provides your plant with the space, drainage and nutrients it needs to grow. Read on for out top tips for repotting a plant.
- Advantages of repotting
- When to repot
- How to repot
- Refreshing a potted plant
Why repot a plant?
Repotting plants is necessary for two reasons:
- Potted soil eventually loses nutrients as they are absorbed by the plant or seeped out through repeated watering.
- Plant roots are constantly growing and your plant can become rootbound if it is not kept in a large enough container.
Repotting is generally a sensible idea for all indoor plants, perennial plants kept on balconies and potted outdoor plants that have to be kept indoors over the winter (such as citrus trees).
When to repot your plants?
Young plants that are actively growing should be repotted every year. More mature plants will generally cope with repotting every two to three years.
You can look out for a few signs indicating that a plant is ready to be repotted:
- the plant is not growing much or is growing shorter stems and smaller flowers and leaves;
- small roots are started to protrude from the drainage holes.
The best time to change pots is generally the start of spring – around March – before the plant enters its main period of growth. Avoid repotting your plants while they are flowering. That said, it is usually a good idea to repot your plants as soon as you buy them as they will often have outgrown their original pots or planters.
Repotting a plant in 4 steps
1. Prepare your tools
You will need:
- a pot with a larger diameter than the one you have;
- a special potting mix;
- materials fordrainage (gravel, expanded clay pebbles, etc.) – unless you are using a self-watering pot;
- the correct potting soil for your plant; choose a ready-made potting mix or create a blend yourself;
- geotextile membrane;
- accessories such as a watering can, hand trowel, secateurs, hand fork, garden sieve, and so on.
- personal protective equipment: gardening gloves and clothing.
2. Prepare the pot
- The base of the pot must contain drainage holes measuring at least 8 mm in diameter. If you are using a large container or a planter, you will need a series of holes spaced around 10 cm apart.
- In the summertime, potting soil on a balcony may be exposed to high temperatures and your plant roots can suffer as a consequence. To protect your roots, you can insulate the inner walls of the container with thin polystyrene (a couple of millimetres thick will do).
- Create a layer at the base of the pot to encourage the potting soil to drain and to prevent excess moisture. This will stop your plant roots from sitting in water. This layer should make up around 1/6 the volume of the container and can be composed of gravel, pozzalana, broken terracotta or expanded clay pebbles.
- For larger pots, you should lay geotextile membrane between the drainage layer and the potting soil to act as a filter. This will prevent your soil from falling through the gaps of the drainage layer. Be sure to rest the fabric against the sides of the pot.
3. Unpot your plant
- Turn your plant upside down (or hold it horizontally) and tap on the bottom of the pot. Holding the pot in one hand, gently pull the base of the stems with the other to ease your plant out.
- It may be necessary to crack or cut your pot open to release the root ball (the compact mass formed by roots and soil).
- This process is easier with a plant that has been temporarily left to dry out: the soil will retract, making it easier to remove your plant. However, you should not attempt to do this during warm weather.
4. Repot your plant
- Gently squeeze around the root ball to loosen it, especially if the plant is rootbound (meaning the roots have spiralled around the pot in a compact circle). This indicates that you have left it too long before repotting.
- Add a layer of potting soil to the bottom of the container and place the root ball in the centre, making sure that it is around 4 to 5 cm from the edges of the pot.
- Fill the area around the roots with potting soil or compost, adding a thin layer over the top of the roots. Pack everything down gently before watering your plant. The earth will settle as you add the water so replenish with soil and water again.
- You can add a thin layer of expanding clay pebbles to the surface of your pot. This will help to regulate the humidity level inside the pot by limiting the amount of evaporation after watering.
- Do not fertilise your plant right away: be sure to way at least three weeks before feeding your plant.
Refreshing the top layer of soil
For plants growing in large pots and containers, repotting can be tricky. An alternative method is to simply remove the top layer of soil, replacing it with a few centimetres of fresh soil.
This method can be carried out once a year around March. This is a viable technique for the following plants:
- rubber figs;
- palm plants;
- lemon trees;
- orange trees;
- heaths or heathers (rhododendrons, azaleas);
- Japanese maples;
Refreshing a potted plant in 4 steps
- Using a trowel, rake down the surface of the pot, making sure not to damage the roots.
- Remove the old top layer of potting soil with a hand trowel and replace it with potting soil and compost or soil mixed with fertiliser.
- Gently pack down the soil then water.
- After a month, fertilise the plant to encourage new growth.
Guide written by:
John, DIYer & IT developer, Brighton, 71 guides
Since I was a child, I was always interested in manual and technical works. Always fascinated by woodworking, I took advantage of my first flat as a playground. On the cards: electricity (of course, safety first!) and some partition walls; but also decorating with the help of the missus, made-to-measure furniture and little tricks to optimise the space, all the while remaining as original as possible. When the little one arrived, I started building bits and pieces for him! Lacking space, I have not got a permanent workshop and certain tools I dream about but are not part of my collection. Not to worry, I already know a lot about DIY and I have a high-tech profile that I hope will guide you in your decisions!