Root Awakening: Lemon plant may lack nutrients

Potting soil may be in poor condition

Is there a problem with my lemon plant? Its leaves have marks and some have turned yellow.

Raghavan Beena

The yellow leaves may be due to a lack of nutrients. You may have to fertilise your plant more regularly.

Check if the soil has compacted, as this will lead to poor drainage and aeration and, subsequently, poor root and plant health. You may need to fork the soil lightly and incorporate some organic matter.

If your plant has been growing in the same pot for a long time, check if the roots have filled the pot. The nutrients in the soil may have become exhausted. If this is the case, the plant needs to be moved to a larger pot.

Check the roots as well to see if they are diseased or infested, as these conditions can also prevent a plant from taking up nutrients from the soil.

Carefully remove the plant from its pot, making sure the root ball does not break apart. Open up girdled roots and fill the empty space in a new pot with fresh potting mix.

Loofah lacks pollination, brown bumps are likely scale insects

The fruit of my loofah plant fall off after a few days of being green and healthy. My bittergourd’s stem has developed brown bumps. What is wrong with my plants?

Lee Yau Hoon

The lack of pollination is likely the reason your loofah plant is not fruiting properly. Are you growing it in a high-rise apartment? The plant’s bright yellow flowers attract bees, which are its main pollinators. But you may need to perform hand pollination – that is, find a male flower and transfer its pollen to a female flower. There are numerous videos online on how to do so.

The bumps on the stem of your bittergourd plant are likely scale insects. They are sap-sucking pests which should be removed promptly.

Use a soft toothbrush to remove as many as you can and then apply a pesticide such as summer oil, which will suffocate any remaining pests on your plant. Apply pesticide thoroughly and repeatedly to manage the pest population.

Fungi appear on moist organic matter

Why is the soil mouldy? I water the plant when the soil feels dry and fertilise it with seaweed fertiliser monthly.

Sindy Ang

Check if your potting mix contains organic components like immature compost and coconut husk powder, as these will continue to break down, especially when moist. The process involves decomposers like various fungi.

Such fungi should not adversely affect larger plants, but the decomposition process may take away nutrients from your plants. As such, you may need to fertilise more if you notice your plants turning yellow and growing more slowly than expected.

Algae may take up nutrients from the fertiliser applied

We are growing tomatoes using perlites and there are signs of algae growth. Is this cause for concern?

Adrian Ling

Algae should be removed as it will absorb some of the nutrients given to your plant. Cover the substrate surface with a suitable mulch, or with materials such as coconut fibre, to block sunlight, as light will increase algae growth.

Tiny spheres are plant’s natural secretions

Why are there white particles on my lady’s finger plant, especially the undersides of the leaves? I spray neem oil weekly, but they keep appearing.

Freddy Tan

The transluscent spheres are the plant’s natural secretions and not pest eggs. There is no cause for concern.