Chye Sim plant infested with leaf miners, whiteflies

When my Chye Sim seedlings were young, they had leaf borers. I removed the infested leaves and sprayed the leaves and soil with sulphur soap. Now, there seem to be whiteflies. I have sprayed the soap solution again, but they keep coming back. What can I do?

Irene Phan

The Chye Sim has been infested with leaf miners. The larvae consume leaf tissue and create tracks as they move along, eventually growing into small flying insects that are hard to control. Although pesticides can be used to control this and the whitefly issue, it is not ideal.

For a pesticide-free approach, consider growing your next crop in a white netted enclosure with supporting structures, custom-made for vegetable cultivation. You can buy these online. The netting should be white with tiny holes to allow sunlight to reach the plants for photosynthesis and growth, while denying adult leaf miners and whiteflies entry to lay eggs.

You can also install yellow sticky traps inside the tents to trap the flying adults and monitor for any early infestations. Do note that sticky traps may unintentionally trap beneficial creatures like lizards and other garden predators.

Mother-in-law’s Tongue needs good light to thrive

I would like to have a Dracaena trifasciata, but cannot seem to keep one alive. Do you have any advice?

Raymond Tan

The Mother-in-law’s Tongue (Dracaena trifasciata) is not an indoor plant and will decline over time if grown in deep shade. Keep it in a location where it can get at least four hours of filtered sunlight, such as by the windowsill or balcony, and in a well-draining growing mix. Let the root zone dry out for short periods between watering sessions, as wet feet will cause the plant to rot.

Rubber plant lacks water

My rubber plant’s lower leaves have started falling and shrivelling. I thought it was due to overwatering, so I cut back on watering sessions. The leaves have stopped shedding, but the remaining foliage is limp and curled. What should I do?

James Sng

Your plant is likely wilting due to a lack of water. Insert a finger into the growing mix to check for moisture. If it feels wet, it is likely a case of waterlogging and root rot preventing the plant from taking up water.

When you water your plant, do so until water trickles out from the drainage holes at the base of the pot to ensure it thoroughly saturates the root zone.

This plant thrives under full sun outdoors. A lack of light indoors can cause leaves to drop. Under sunnier conditions, plants will transpire more and evaporation will cause the moisture in growing media to evaporate too. Under such conditions, plants need to be watered more often.

Do not mix your own hydroponics fertiliser

I grow leafy vegetables on my balcony using the Kratky hydroponics method. I am trying to reduce costs by mixing my own nutrient solution concentrate. Some online research suggests mixing NPK (nitrogen, phosphorus and potassium) with Epsom salt and calcium nitrate. Can you weigh in on this? Will different NPK ratios affect the concentrate?

Chew Soen Ping

Commercial hydroponics fertilisers contain all the nutrients in a stable, soluble form that can be readily taken up by the plant. The exact compounds used to make fertiliser pellets or NPK solutions are not made known to consumers.

If you decide to use pelleted or water-soluble NPK fertilisers for soil-grown plants and mix them with other mineral salts to make your own fertilisers, you may cause an undesirable chemical reaction that may make certain nutrients unavailable to the plant. It is best that you use commercially available fertilisers.