CHECK FOR ROOT ISSUES, MAKE SURE PLANT HAS ENOUGH WATER

Why are the leaves of my plant browning?

Audrey Ong

Your plant is likely a Buddhist Pine (Podocarpus), which is a common bonsai candidate.

The browning leaves may be due to a root issue or a problem with the plant's ability to take up water. It looks like the roots have completely filled the pot, meaning that water is taken up quickly. This can happen very fast on hot and sunny days.

When water is lacking, it can cause the plant to eventually wilt.

You may want to move the plant to a larger pot, water it more often and provide it with some shade on hot days.

Also, consider taking the plant out from its pot carefully to check the health of the roots.

Healthy roots should appear firm and white, while dying or diseased roots will be dark and mushy.

Diseased roots prevent plants from taking up water and must be pruned, and the plant must be repotted in fresh soil afterwards.

Place the plant in a cool, shady spot to recuperate.

You can return it to its original growing location under the sun once new roots and leaves have formed.

MOIST SOIL MIGHT HAVE CAUSED LEAF YELLOWING

What is causing the discolouration of my Monstera deliciosa?

I bought it a couple of months ago and it has produced new leaves, but they eventually yellow at the edges.

Olivia Low

Are you keeping your plant's growing mix moist and in the shade?

In a shady location, moisture in growing media will take longer to evaporate. Constant wet feet may have caused the yellow edges in your plant's leaves.

Most plants benefit from periodic drying and wetting of the root zone so oxygen in the air can reach the roots. Let the root zone dry out slightly before watering it again.

Also, the Monstera, although regarded as a shade-tolerant plant, grows best in a location with filtered sunlight and good air circulation.

MILLIPEDES MAY MULTIPLY WITH FRESH-LAID WOOD-BASED MULCH

After landscaping works were completed at a nearby condominium, many caterpillar-like worms have appeared in surrounding areas, including my garden.

Every day, there are worms crawling over the walls and there seems to be a nest somewhere. How can I get rid of the pests?

Tammy Lim

The pests in the picture are millipedes. They are decomposers that break down plant waste.

It may be that the landscaping works involved the use of wood-based mulch to lay on the newly landscaped areas.

Partially decomposed wood mulch serves as food for millipedes and might have caused the surge in their population numbers.

You can try using chemical pesticides, but these may not fully eradicate the pests. Their population should decrease over time once the wood waste mulch has completely broken down.

When you or your neighbours are landscaping, it is best to use mature, high-quality compost or finely chipped dried leaves to avoid issues with such pests.

NERVE PLANT MAY FARE BETTER IN AN OPEN AREA

I have a closed terrarium in my office, which has air-conditioning and overhead lighting. The larger leaves of the plant inside are curled. New leaves are sprouting, but the growth is slow. Why are the leaves curled? There is condensation on the jar and I open it for about 20 minutes a month.

Rachel Low

Not all plants are suited to sealed terrariums. Your Nerve Plant (Fittonia cultivar) will fare better in open terrariums or a dish garden.

In a sealed terrarium, the lack of air circulation and heat build-up - which happens if there is artificial light overhead or the container is placed near a sunlit window - can lead to stressed plants with leaf development issues.

The ceiling lights do not provide enough light for your plant to grow. Try using a desk lamp instead and placing it close to the plant - about 10cm to 20cm, depending on the intensity - to support plant growth.

POT IS TOO SMALL FOR CHILLI PLANT

My chilli padi plants are dying. The leaves are drying up, even though I have watered them every day since planting them from seeds last January. The leaves started to wilt about two weeks ago.

I had been fertilising them every three to four weeks with chicken poo and flower bloom fertiliser. The soil is 50 per cent "bio-organic" compost, 25 per cent perlite and 25 per cent vermiculite.

Rachel Tang

Your chilli plant seems to be pot-bound - that is, the roots have filled the pot and the amount of moisture held by the growing medium is quickly taken up by the large plant.

You may want to move it to a larger pot, where there will be more space for the growing medium to take up water for the plant.

You may also need to water it more than once a day, depending on how hot and sunny it is.

Your plant can grow even bigger, depending on the size of the container it is grown in.

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•Answers by Dr Wilson Wong, an NParks-certified practising horticulturist, parks manager and ISA-certified arborist. He is the founder of Green Culture Singapore and an adjunct assistant professor (Food Science & Technology) at the National University of Singapore.

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