The sequence of potting on, although a very simple process, needs to be explained in detail for the novice and new enthusiast. The technique outlined below will also help exhibitors in their quest for perfection. Once cuttings have been propagated or purchased they will require potting up, initially into 5 cm to 7.5 cm pots, then progressively into larger pots until their final potting usually late spring / early summer ready for flowering. See chapter on 'Methods of Propagation'.The sequence of potting up is extremely important to maintain regular and even growth. As plants grow, their roots spread out in search of food and moisture until they reach the inside edge of their pot. When they will need potting up into a larger sized pot . This is to enable progressive and uniform growth. If potting up is not done correctly the plant will not grow and flower as expected. It will have under sized leaves and flowers. The accepted norm for potting on plants is to get a plant pot 2.5 cm to 3 cm larger, put fresh compost in the bottom, place the plant on top , fill in the sides and then water in. I used this method for a number of years and found several drawbacks. Firstly, I noticed that every time I potted up my show plants there was a reduction in leaf size. This was even more pronounced when growing standards. You could literally see what stage the plant was at when potted up by looking at the leaves. Being root-bound the answer was simple, it was starving and in need of fresh compost or supplementary feeding. Once potted up it would take some time before the roots grew sufficiently to gain access to the nutrients in the new compost. During this period the plant would be watered maybe once or twice a day. The soluble nutrients contained in the new compost would be washed out through the bottom of the pot. The plant continued to be undernourished until such time as the roots were able to penetrate the new compost. Secondly, a percentage of plants would not establish themselves in the new compost for various reasons mainly associated with over watering. The tiny feeding roots would turn brown and start to rot. Some plants will recover but most will need to be discarded. Thirdly, with second and third year plants, there is a lot of unsightly ripened wood at the base which detracts from perfection, especially for show plants. With these drawbacks in mind I decided to change the whole process of potting up.
The series of photographs illustrate the new process which transformed my plants and eliminated most of the problems outlined above. Once a plant is root bound and ready for potting on, (see photo 1) water it well and allow the surplus water to drain away. Select a pot about 2.5 cm to 3 cm larger. If it is a clay pot soak it for a few minutes so that it will not absorb moisture from the new compost. Instead of putting 3 cm to 4 cm of new compost at the bottom of the pot just barely cover it with about half a centimetre. (see photo 2) This is to cushion the roots from coming into contact with the new pot. The roots are gently teased out of the root-ball which is then placed as deep as possible into the new pot. Fresh compost is gently eased down the sides and the remainder on top of the root-ball. (see photo 3) This effectively corrected two of the problems, that is, reduced leaf size and unsightly wood. By lowering the root-ball in the pot a proportion of old wood was buried lowering the root ball, but more importantly, the plant was nourished immediately without waiting for the roots to gain access to the new compost. The difference being, the soluble nutrients in the new compost are washed down into the root ball each time the plant is watered enabling it to continue normal growth. (see photo 4) A further benefit was discovered when the compost from the top of the pot was washed away at the end on the season. It revealed something unexpected, the old ripe wood that had been buried, had rooted assisting the plant even further. (see photo 5) On occasions, I have also removed a small proportion of compost from the bottom of the root-ball to lower the root ball even further.
Ready for potting up
Next size pot
Extra root system
Provided the plant was watered before potting up do not water again for at least twelve hours or until the plant shows signs of distress. This encourages the plant to send roots into the new compost and reduces loss through root decay. The techniques outlined above were motivated by the desire to produce larger and more floriferous plants for exhibition. Using this method will also help keep plants neat and compact. Needless to say these methods were never discussed when I was actively engaged exhibiting.