How should the settling-in water for orchids be watered correctly?
When is the right time to water the settling-in water? It depends on the situation. If you are only repotting without dividing the plant, without pruning the orchid roots, and without injuring the orchid roots, you can water immediately. The benefit is that it can reduce the damage to the orchid caused by repotting and shorten the time needed to establish. If you divide the plant or prune the orchid roots before potting, you should wait a few days before watering. How many days exactly depends on the moisture of the potting medium at the time of potting...
Orchids are prone to stem rot (rot of the pseudobulb base) after division, and this is closely related to watering the settling-in water immediately. Many orchid books and many orchid growers online say to water the settling-in water immediately after dividing and potting, but in fact this is a bad habit.
Based on years of practice, I have found that delaying the settling-in water is greatly beneficial for preventing stem rot.
The method is: after dividing the plant, let it dry, then pot it up with dry potting medium, and water the settling-in water three days later!
This method is also used for repotting and for planting newly purchased orchids.
Because dividing plants in hot weather makes stem rot more likely, it is best not to divide plants in hot weather (March to September in Shenzhen), and also not to buy freshly divided plants.
Since I started growing orchids in 1993, I have always used Method A. Comparing the two, I feel Method A has a hundred benefits and not a single harm. The major premise is: "Use slightly moist soil, do not pot up with soil that is too dry."
Argument: No matter how careful the operation, no matter how meticulous the protection, the orchid will definitely be injured during the process of moving, just to varying degrees. Watering immediately forces the orchid to go right to work, and it is certainly not as good as waiting 2 days, letting the orchid adapt to the environment and, because of the slightly dry conditions, letting the "wound" heal and contract. Watering the settling-in water this way is the best approach. Perhaps many people have used the method of watering the settling-in water immediately for many years and their orchids are still fine. But the two are similar: with the former you scored 90 points, and your classmate with the latter scored 85 points. The difference is very small, but it does exist.
Results: Compared with Method B, the plants under Method A have several not very obvious advantages, but they clearly exist: 1. The plants re-establish quickly and regain vigor quickly. 2. There is much less disease during the re-establishment period. 3. New shoots come relatively quickly 4. Roots do not rot easily.
Experimental method: Use 2 pots of weak seedlings with basically the same condition, and apply the 2 methods at the same time. This best demonstrates the difference between the two.
One cause of root rot: As everyone knows, strong fertilizer and heavy watering can both cause root rot. Once root rot appears, people always look for the cause in fertilizer and water, attempting to prevent root rot through controlling water and controlling fertilizer. But sometimes the water is controlled and the fertilizer is not applied, yet the roots still rot. What exactly is the reason? This often neglects one very important cause of root rot: watering the settling-in water too early after pruning the orchid roots and potting up! After root pruning, the wound generally needs some time to heal. The moisture of the potting medium is the most important factor determining the wound healing time. The lower the moisture of the potting medium, the faster the wound heals ("moist" potting medium generally allows healing in about 3 days). The higher the moisture, the longer the wound takes to heal, or it may even fail to heal. If the settling-in water is watered immediately after pruning the orchid roots and potting up, then even if a fungicide was applied before potting, the wound will find it difficult to heal. Once bacteria infect it, that is the beginning of root rot, and it spirals out of control. The pruned orchid roots will rot along their entire length, while the new roots remain intact. Therefore, when you find that the new roots are intact while the old roots and the pruned orchid roots are rotting, this is the trouble caused by the settling-in water.