No house-plant suffers from having itsexamined. Take the pot and turn it upside down with the fingers over the soil and the plant projecting between the first and second fingers. Then give the edge of the pot a sharp tap on some firm surface. The ball will fall out of the pot into the hand. (Make sure, incidentally, that the soil is comparatively moist when doing this or dry soil from the surface will tend to be shaken out.) If the plant needs you will see that the are curled tightly around the perimeter of the ball and that almost all of the soil appears to have disappeared. And if on the other hand there still appears plenty of space and plenty of soil for the roots, then you can slip the ball back into the pot and it will have come to no harm.
When re-, make sure first that the hole or holes at the base are not so large that the will fall through. Today most are of plastic and have a series of smaller holes rather than one large one in the centre. Then scatter in I in. or so of good compost. This can be John Innes Compost, available in small quantities from many chain stores and nearly all garden centres or it can be one of the peat-based soil-less composts such as KERIMURE or LEVINGTON. DO not mix the two types, or try to re-pot a plant in a different type of mixture.
Slip the root ball into the pot on top of the I in. of soil on the base of the new pot and then sprinkle more soil around the root ball and inside the pot to fill the space between the two. Firm the soil well with the thumbs and fingers and add more soil until the surface is about in. from the rim of the pot. This will give space for. Water the re-potted plant well and then stand it in a cool, shaded place for a few days to recover.
Changing the soil: This is all very well, you may say, but what am I going to do about my rubber plant that nearly reaches the ceiling, and what about the cissus that is trained to cover the wall ? Obviously these plant pots cannot be picked up and handled in the same way as just described so we have to find some other means of refreshing or renewing the soil in these pots without even moving them from their static positions.
These large pots and even many small ones can gain a considerable ‘shot in the arm’ by changing just some of the soil. Gently scrape away some of the soil on the surface, in., 1 in. or even more if the roots are not yet obstructing you. Scrape away this soil and throw it in the garden, certainly do not attempt to use it again for any pot plant. Then add fresh John Innes compost or other appropriate planting medium to the top of the pot to replace that you have removed. Firm it down and do not let the level become so high that watering is a problem. Once again water thoroughly and then leave the plant alone until the soil is almost bone dry before you water again.
Given careful watering andmany plants will live for years in the same pot. It may be true that they will grow more vigorously and more quickly if they are re-potted more frequently, but this is not always an advantage. So long as the plants remain in good health and attractive appearance they are continuing to serve you well.