Marie writes: I have a type of water-plant called “bambu air” which grows in a pot of water. How do I prevent mosquitoes from breeding?
Mosquitoes need calm water for breeding, and can do this in a very small quantity of water; 5+cm in a discarded can is sufficient. Your pot of ‘bambu air’ would be quite enough. Control methods will depend on the size of the pot.
If your pot is small (say up to 20cm in diameter) ½ - 1 teaspoon of cooking oil added to the water will do the trick. The wrigglers (larvae) have little, feathery tubes at the tail end of their body. These must be raised above the surface of the water in order for them to breathe. The thin film of oil clogs these tubes and they die of asphyxiation.
A similar amount of kerosene is even more effective and somewhat cleaner, as it does not ‘clump up’ as the cooking oil tends to do. In either case, you should make a point of completely emptying the pot at weekly intervals. Give the pot a good clean, replace the plant, in clean water and add new oil/kerosene.
This plant is usually sold in small, tight bundles tied up with narrow, red ribbons. It grows rather quickly and the ribbons tend to strangle it somewhat as time goes on. Replace these ties as often as it appears necessary, being careful not to make the ties too tight.
If the pot is much larger, it would be better to buy some small aquarium fish which do not grow much larger (eg: the tetra group). These will quickly gobble up eggs and wrigglers. They should not need extra feeding as they also eat algae, which forms quickly in the tropics. Refresh the water by trickling new water into the pot weekly, being careful not to flush out the fish.
Stephanie, Ubud writes: I am living in Ubud for the next seven months and have bought three lotus plants in large cement basins of about 1 m in diameter x 75 cm in depth. Two of the plants were situated in a large pond at the nursery where I bought them and have leaves and flowers with very long stems.
To transport the plants to my home, the lotus were placed in the cement basins with little water and soil present. I have added soil and water but am afraid I may have put too much soil. Should the soil cover the roots by much? Is there a rule? I have cut back dead flowers and leaves but should I also cut back the good leaves with the very long stems in order to leave room for the new growth to flourish? The long stems are taking up a lot of space. I have read that the plants need full sun but can there be too much sun?
Today, one of the blooms, instead of closing by the end of the day, wilted in the sunshine and is now drooping. I also notice the water in the basins gets very warm. One of the basins is placed in a spot where it gets morning sun. The other two basins get full noon-time sun until at least 5 pm; one of these basins is where the flower wilted away.
The natural habitat for lotus is as you saw at the nursery where you bought them. Roots down in deep, cool mud, surrounded by much more water than your basins can provide. About 30% soil is enough, so adjust this. Do not cut away healthy leaves and stems – they are the plants’ food factory.
Full sun in the tropics is very different from full sun in temperate climates. Remove the plants in full sun to morning sun only; I have seen lotus grown successfully in dappled shade. You will find that as the lotus adapt to the basins, they will develop shorter and fewer stems and smaller leaves. The basins will then not be quite so crowded. Alas! You may also find that the flowers may be somewhat smaller, but they will be in proportion to the stems and leaves.
Water temperature is also quite a significant factor. The drooping flower stem will have been likely ‘cooked’ a little and probably did not recover. Test the temperature of the water around 12 noon, and if you feel it necessary, run cool, fresh water into the basins as a preventative measure. Allow this water to trickle in and run over the sides of the basins. If the water is replaced too quickly, it will also take some of the soil with it. This may mean that nutriments are washed away also. Replace these with some liquid fertilizer a little at a time and applied on a weekly basis.
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