Most house plants need to be repotted annually: the best time to do this is in spring when your plants are beginning to grow again after a winter period of slow or very little growth. Make the first task of the growing year a spring cleaning exercise for your house plants. Here, you will find out how to repot those that need largerand refresh the potting mixture of those that stay in the same pots.
It is a good idea to give your plants a thorough check in February or March to see if they need bigger pots. Any that are-bound – their may appear through the holes, or over the surface of the potting medium – will definitely need to move into larger pots. Repot into pots just one size larger. Overpotting may result in a stagnant potting mixture that the roots cannot fill quickly enough and this could lead to rot.
Some plants may be in the maximum size pot that suits them, but they can still be repotted. For them repotting will replenish the minerals and trace elements that they have taken from the potting medium. Even if you have beenyour house plants regularly, many of the microscopic nutrients that were in the potting mixture will have been used up by the plants.
Potting into a new pot
- Place the palm of one hand over the surface of the potting mixture and turn the plant upside down. With your other hand tap the base sharply.
- The plant should slide out easily. Before you repot use an old kitchen fork to remove weeds or moss if on the surface of the mixture.
- Place a little potting mixture in the new pot, so that the plant is at the same level as in old pot. Use the old pot as a mould for .
- Set plant in the new pot and fill any gaps between rootball and sides with potting mixture. Firm the plant in with your hands or use a tamping tool.
- If your plants are too large to repot, top-dress them with new potting mixture. Remove as much of the old potting mixture as you can without damaging or disturbing the roots then refill with fresh potting mixture.
- Don’t assume that all of your plants will need new and larger pots. There are some plants that bloom better with cramped root conditions. African violets, for instance bloom better if they remain in 7-10cm (3-4 inches) pots. If they are repotted into larger pots they may not thrive.
Equipment for repotting
When you begin your spring repotting, make sure you have everything you need ready and within easy reach before you begin. You will need clean pots, adequate potting mixture– either soil-based or peat-based, depending on the needs of the plant you are repotting – drainage materials, canes for support, scissors and an old kitchen
When to repot
Never repot when roots are just beginning to grow into the compost. The rootball will not be well-formed. The rootball is established and the roots are growing well. Repot unless the plant grows better with a crowded root system.
The plant is root-bound – there is no more room for the roots to spread. Repot the plant immediately.
Levelling your plant
When you re-pot plants it is important that they are placed at the same level in the new pot as they were in old one. Place a layer of drainage material and compost in the pot, then place the plant on this layer to check the level.
- Remove the plant from its pot and have ready a clean pot of identical size. Use a stick, fork or hands to gently tease away half the old potting mixture.
- Put fresh potting mixture into new pot. Place rootball in it and fill the spaces between it and the pot with new potting mixture. Press down to firm.
- Water the plants the day before repotting as this helps when removing the plant from its pot.
Before you start repotting see that the new potting mixture is moist. Place some drainage material, if necessary, and a layer of potting mixture in the new pot. (Add drainage material if you use clay pots or commercial potting mixtures which are not free draining.)
Place the old pot inside the new one to give you an idea of how much potting mixture you will need to fill around the rootball. Place the plant on the layer of compost and check that it is set no higher and no lower than it was previously. Fill any air spaces between the sides of the pot and the rootball with potting mixture. Tap the pot on the table to make sure the mixture settles down.
After repotting don’tfor the first 4 weeks. This encourages the roots to move in search of nutrients. Resume after 4 weeks, when the roots should be well-established in the pot.
Usually the rootball will slide easily out of the pot. If not knock the rim smartly against a table. When a plant is pot-bound in clay, break the pot with a hammer. Use pliers or secateurs to cut a plastic pot.