Although it may be hard to believe with the latest covering of snow we have had, but spring is just around the corner and the new growing season is about to get underway. For your house plants, the lengthening days are a stimulus to new growth and March or April is the best time for houseplant repotting or top dressing. Repotting in early to mid spring gives the roots plenty of time to establish before the next dormant period and there is less chance of your plants sitting in a waterlogged pot over winter.

As a general rule houseplants benefit from being repotted every couple of years but different types and different growing conditions can affect this greatly. Most indoor plants thrive best if their roots are restricted and some plants will only flower when in this condition so the first things to consider are the growing requirements for the type of house plants you have. Only repot your plants that are definitely pot-bound.

The main signs to look for are roots growing through the drainage holes, the soil drying out quickly causing frequent watering and very slow growth even when the plant has been fed during the previous years growing season. When a pot-bound plant is removed from its pot there will be a cylindrical matted mass of roots and not much soil will be visible.

Choose a pot that is only slightly larger than the previous one, 1-2 inches in diameter and depth is ideal. If you are using a pot that has been used before, then make sure it is thoroughly cleaned to prevent the spread of pests and diseases. Use good quality multipurpose compost or one that has been specially formulated for houseplants. Plants with fleshy-roots like an open compost and a course perlite may be used to improve drainage. Plants with fine-roots prefer a fine textured compost and horticultural grade perlite may be added or vermiculite, this will hold moisture for a bit longer and prevents the fine, sensitive roots from drying out.

Before you pot up your plant it is a good idea to remove any roots that are damaged or diseased with a sharp knife. And if there are any large coils of roots that have grown around the bottom of the old pot these can be removed also. Gently tease the roots out of their rootball to help speed up growth and branching of new roots into the fresh compost. After your plant is repotted it will need to be watered-in and placed out of direct sunlight for a week or two. Misting the leaves daily with water will help to prevent wilting. The plant can then be treat normally although it will not require any plant food for a few weeks because the new compost will contain nutrients.

You may decide that your plant is big enough and not want to keep increasing the pot size. In this case the pot should be top dressed by removing the top 1 or 2 inches of compost, depending on the size of the pot. This compost needs to be replaced with fresh compost.

If the plant is old and has been in the pot for many years it may be time to root prune first and then use a clean pot the same size as the previous one. About a quarter of the soil ball can be removed together with the outer dead roots. It may be possible to do this with your fingers or an old kitchen fork can be used. Some of the top growth can also be trimmed back after repotting if the plant is becoming too large.

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