Root Awakening: Spider plants may have been grown too deeply

Spider plants prefer to be grown in a well-drained and aerated mix which dries out in between each watering. PHOTO: RUTH LOW

Spider plants could have been buried too deeply or grown in moisture-retaining mix

My spider plants have been growing well until lately. The new shoots have black tips and the area where the leaves grow out together has turned black too. What is the cause of this problem? I repotted the plants recently into a bigger container and they are placed near the window and get filtered sunlight.

Ruth Low

The issue appears to be a common one.

During the propagation or transplanting of spider plants, a common practice of gardeners is to stabilise the plant in its new pot. Depending on the size of the plant, it may wobble in its position, so there is a tendency to bury it deeper than it should be.

A plant that is buried too deeply will have growing media getting into its centre and in between the leaves. This can cause parts of the crown to rot, leading to the symptoms described.

Some growing media, especially those that are made up of largely organic material, tends to hold too much moisture.

Spider plants prefer to be grown in a well-drained and aerated mix which dries out in between each watering. If a plant is grown in a mix that does not dry out sufficiently, the crown can also rot.

Note that a larger pot of growing media will also hold more moisture that takes longer to dry out.

You can either time the watering of your plants accordingly or incorporate gritty materials like pumice or fine expanded clay pellets to help open up your growing media. Use a pot of the right size in accordance to the plant size.


Giant Peace Lily may have dried out excessively

The Giant Peace Lily is a plant that is better suited for a location with filtered sunlight. PHOTO: NATALIE SIMANDJAJA

This plant was in a sunny balcony for half a day and the leaves wilted. I have been trying to revive the leaves by watering, but am unsuccessful. What can I do?

Natalie Simandjaja

The Giant Peace Lily is a plant that is better suited for a location with filtered sunlight.

Exposing the plant to direct sunlight for half a day will likely cause sun burn. If the plant was not deeply watered before, it could have dried out excessively under such harsh conditions.

A dried-out plant will have damaged roots, which can no longer uptake water even if it was given water. That explains why the plant did not revive even after it had been watered.

Plants that have suffered such a condition can be difficult to revive without professional help.

Experienced gardeners may resort to pruning some of the large leaves to reduce water loss via transpiration.

The plant may then be enclosed in a transparent plastic bag to help conserve moisture.

The root zone is kept moist at all times and the plant is allowed to recuperate in a bright and cool spot where new roots may be produced with time.


Green spathe appears on aged inflorescences of the peace lily

Although the peace lily is often regarded as a shade-tolerant plant, it does better if it gets at least six hours of filtered sunlight. PHOTO: JANICE TOON

Why are my white peace lily flowers turning green? They were white when I bought the plant from the nursery, but after a few weeks, they turned light green and are now all dark green. The plant is on an airy bright balcony floor, but the space does not get sunlight.

Janice Toon

The green colour of the sail-like spathe of your peace lily is a sign that the inflorescence is ageing and will fade away after some time. The spent inflorescence can then be pruned.

There is no cause for concern and new inflorescences produced will start off with a white spathe, which is typical of the species.

Although the peace lily is often regarded as a shade-tolerant plant, it does better if it gets at least six hours of filtered sunlight, leading to better growth and plant health and the production of inflorescences.


White patches on pandan leaves could be due to spider mite infestation

The appearance of lighter green leaves in plants could be due to a lack of nutrients. PHOTO: SHAWN SEAH

I notice the deep green colour on the leaves of my pandan plant seems to have faded, There are also white patches on the leaves. What is causing this?

Shawn Seah

The appearance of lighter green leaves in plants could be due to a lack of nutrients.

Did you fertilise your plant regularly? The presence of organic materials such as partially mature compost and coco peat in growing mixes can cause further problems - they drain plants of nutrients as they decompose further.

It is best to use mature compost if you are incorporating organic matter to your growing mixes.

The white patches could point to a spider mite infestation. Look under the leaves and see if you can find small red spots that move. These pests are common in high-rise growing environments.

If you do not want to use pesticides, you can wash the pests off regularly. Ensure that your plant is growing under optimal conditions - with sufficient sunlight, humidity and air movement. Stressed plants are prone to pest issues.


Old leaves turning yellow and drying off are natural part of the growing process, but plants may also lack fertilisers

The yellowing of older leaves could indicate the lack of nitrogen. PHOTOS: ROSALIND SOH

These two plants have new shoots yet their leaves are always turning yellow. Why is that so?

Rosalind Soh

If the yellowing leaves of your plants - the money plant (botanical name: the N Joy cultivar of the Epipremnum aureum) and marsh pennywort (botanical name: Hydrocotyle verticillata) - are the older ones, there is no cause for concern if there are just one or two at any one time. This is the natural process of plant growth where older leaves are shed and new ones are produced to replace them.

Another possible reason could be a lack of fertilisers. The yellowing of older leaves could indicate the lack of nitrogen. Most fertilisers contain this nutrient and can be given to plants to promote growth and remedy this issue. Ensure that the soil is aerated and well-drained, so roots can be healthy to uptake nutrients for the plant.

Also, check if there are pests on the underside of leaves of your plants. Pest attacks can cause leaves to turn yellow.

In addition, make sure the plants are never allowed to dry out totally where they wilt. A parched plant will lose some leaves.

  • 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.
  • Have a gardening query? E-mail it with clear, high-resolution pictures of at least 1MB, if any, and your full name to stlife@sph.com.sg. We reserve the right to edit and reject questions.

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