Two main factors are responsible for repotting your orchids and most often, but not at all times, happen simultaneously. In the first case, you need to re-pot an orchid if it grows beyond the capacity of the pot. In other words, the orchid needs to be repotted when it grows too large for the pot it is grown in. Usually, the root system of orchids is extensive inside the potting mix and the pot. However, they also have typical roots that grow outside the pot or some new roots may emerge out of the potting mix into the air. All these are common behaviour of orchids and they do not suggest that you need to repot the plant. On the other hand, if you find that the pseudo bulbs of the plant are hanging outside the pot or the new roots are unable to find accommodation in the pot at all, you should know that it is time to report the orchid. Another instance when you need to repot your orchid is when the potting mix has gone moldy. If the potting mix you are using comprises natural materials, most of them will decompose with passage of time and disintegrate into fine, firmly packed mix and does not allow air to pass. When the roots do not receive air, it is natural that they will die. Hence, your orchid too will be doomed if you do not take the plant out of the compressed potting mix.
In order to know whether you need to repot your orchid, you ought to brush away the top surface of the potting mix and examine the materials below to see if there are signs of decomposition. Just sink your finger up to the second joint into the potting mix and if it goes in easily, you should be sure that it is time to repot the orchid. More effective substantiation include signs of decomposed roots, which will be blackened, greying or their will be mushiness and brittleness. It is worth mentioning here that different potting media will deteriorate at different times in different conditions. For instance, a potting mix comprising bark pieces will remain well for roughly two years. On the other hand, finer pieces are likely to decompose in just a year. Potting media comprising tree fern is likely to last for anything between two and three years, while rock will never deteriorate. Therefore, it is advisable that you use a potting mix comprising decomposing as well as non-decomposing materials, as they will help in lengthening the period between repotting.
Repotting orchids is always considered to be a difficult exercise just because people typically repot their plants at the wrong times. And when repotted at a wrong time, orchids express their antipathy over the bad timing. Hence, timing is of utmost importance when you are repotting your orchids. It is a very crucial part of growing orchids. In fact, orchids pass through a growth cycle. First the new pseudo bulbs appear, then the leaves and roots, which elongate. Once the leading growth is over or the leaves have matured, the plants generally have a rest period. Thereafter, the plants give rise to spikes and sheaths, which are typically followed by bearing buds and flowers. Nearly all orchids set off their new growth during the latter part of winter or in spring. Whenever you repot an orchid, it disturbs the plant's growth. However, compared to other plants, orchids are more tolerant of mistakes during the repotting process, provided they are repotted at the appropriate time. Generally speaking, the ideal time for repotting an orchid is when the plants just start growing new roots and before the new roots attain a length of � inch. In the case of most plants, this takes place soon after their flowering season ends. In other words, almost all repotting activities should be ideally taken up between February and June. On the other hand, if you leave the plant for a long period even after the commencement of its growth cycle before repotting it, the plant will have a difficult time to re-establish itself in the new pot and potting media. In case the roots of the plants break or are damaged during the repotting exercise, the plants will not produce the branches essential for developing a healthy as well as extensive root system. In such instances, the plants require additional energy to produce the root tips damaged during the repotting. Plants take this energy from the energy it uses for flowering. On the other hand, if you repot the plants at the right times, orchid will bear flowers in due time in the following year. Then again, when you are handling the new roots of orchids when they are still tiny, it will mean another minimum impediment for the plant. You ought to bear in mind that the new roots are exceptionally fragile and the chances of breakage is less provided the roots have grown up to a length of 1 inch. If you repot your orchid at this time, it will provide the plants with the longest growing time before they are repotted again. It will also cause the least disturbance to the plants and they will start growing well in the fresh potting mix. In addition, the plants will remain healthier provided they are able to re-establish themselves before they go into the rest period. The rest period of orchids denote the time when no new growth activities take place in the plant.
At times, an orchid may need urgent repotting as the potting mix has deteriorated to such an extent that it is killing the plant. Another occasion is when the plant has excessively overgrown its pot. However, if you keep waiting for the suitable cycle to repot the orchid, it may result in damaging the plant's roots further. In fact, it will hurt the plant more than what it would experience during repotting. It is important to be as gentle as possible while you are repotting plants out of time. You need to be very watchful during the repotting process as well as afterwards. In case, you notice that some of the roots of the plant have already rotted, you need to clean the roots and pot the orchid into a much smaller pot. Having done so, you need to wait till the normal repotting time of the plant, and repot it again as usual. Here is a word of caution: never water the repotted plants overly, but provide them with just the right amount of moisture. Orchid growers may come across another possible situation when the plant overgrows, but the potting mix has still not deteriorated. In such a situation, a procedure known as "dropping on" may prove to be useful. In such a scenario, you need to take out the overgrown plant from the pot and place it along with its potting mix and other materials into a larger pot. Subsequently, add more fresh potting mix to fill in the gaps in the larger pot. When you undertake the "dropping on" procedure, it causes least disturbance to the roots and is a good enough means to repot plants even at the right times provided the potting mix is still in a good condition. Interestingly, some orchids, such as Cymbidium, have a preference for somewhat decayed potting mix actually perform better when you undertake the "dropping on" process to repot them. At other times, you may undertake the typical full repotting for these orchids too. There is another effective way of dealing with overgrown sympodial plants that climb over the pots' surface. In such cases, it is best to place another pot of similar height beside the first pot so that the second pot can accommodate the suspended roots and pseudo bulbs. Ensure that the second pot is made of plastic as it will enable you to cut it in a V-shape section along the rim to make it fit properly below the overhanging growths. Place the second pot below the new overhanging growths as well as the roots in such a way that it is able to accommodate them. Next, fill the new pot with fresh potting mix. Once this is done, use a tape to bind the two pots together side-by-side along their rims. This will hold the new pot in the place and prevent it from moving away. When the process is complete, it will enable the overgrown parts of your orchid to establish them in the new pot with the least amount of disturbance. At the proper time, you will be able to lift the entire plant and transplant it into a bigger pot. Alternatively, you may also divide the plant easily with breaks at any natural point between the two pots. You need to bear in mind that you should never report your orchid when it is either in bud or bloom. You need to wait for repotting until the plant has completed bearing flowers. This is important because if you repot a plant when it is in bud or flowering it is bound to cause immense trauma to the plant which will, in turn, lead to the dropping of the buds and flowers. If your orchid has a flower casing, but there is no evidence of a bud inside, or if the spike is still small and does not have any bud, you may go ahead and repot the orchid, if you feel it is necessary. Moreover, some orchids that have been acquired newly may also need repotting if the potting mix appears to have deteriorated. Repotting of such plants may also be necessary if they have overgrown. Nevertheless, you should always allow the plants a month's time to acclimatize themselves in their new growing conditions before you repot them. In addition, you should also give them enough time to recover from the trauma of growing in a new environment. Repotting the plants at this stage will only add to their trauma.