Root Awakening: Custard apple may need hand pollination

The custard apple's flowers (left) are naturally pollinated by beetles, while cages can protect fruit from the common palm civet (right). PHOTOS: RACHEL EU

Custard apple may need hand pollination to produce fruit; keep palm civets away with steel protectors

My three-month-old seed-grown custard apple plant is about 30cm tall and budding. Should I plant it in the ground? How long will it take to bear fruit and what insects are needed to pollinate it?

I also photographed a cat-like animal eating the fruit of my chiku plant at night. The animal tears off plastic bags and netting. What can I do to protect my plant?

Rachel Eu

Your custard apple plant is still small and the pot should be able to host it for a while more. Some gardeners grow these plants in large pots.

Custard apple flowers are naturally pollinated by beetles. This plant’s flowers start off as female when they open in the afternoon and they progress to the male stage the following afternoon, at which point you can collect pollen and brush it onto the sticky surface of the centre of a different, newly opened flower.

The animal in the picture is the common palm civet. Try building cages out of stainless-steel wire mesh to protect the fruit. Ensure the cages are large so that there is ample space between the fruit and the mesh. If the cage is too heavy for the plant’s branches, use a bamboo or wooden stake to provide support – stick one end of the stake in the soil and tie the other to the cage.

Different types of fertilisers

You recommend different fertilisers for different plants. Could you elaborate on these? The nursery near my home sells fertilisers for flowering and non-flowering plants in plastic containers with no details. I also use chicken bone powder for my outdoor plants.

Raghavan Beena

There are many different types of fertiliser products. In general, organic fertilisers tend to contain less nutrients than chemically formulated ones. The former may also not have all the required nutrients and usually contain more nitrogen.

Fertilisers can be divided into slow-release and fast-acting types that are sold in the solid form. Slow-release fertilisers may be organic and are made of processed animal materials such as chicken manure, blood meal or bone meal. These break down over time to release nutrients. However, there are also fertilisers in the form of chemical-based coated pellets that gradually release nutrients over time. Fast-acting fertiliser pellets are usually chemical-based, not coated and dissolve readily to release nutrients whenever you water your plants. There are also liquid fertilisers, as well as those in solid powdered form that need to be dissolved in water before they are applied. These can be organic or chemical-based.

Fertilisers come in many different nutrient compositions. A reputable brand would include the relative amounts of nitrogen, phosphorous and potassium in the NPK ratio on its label. These are the primary nutrients that plants require in larger amounts for growth and reproduction. Depending on the formulation, the manufacturer will also list the composition of the secondary and micronutrients that can be found in the fertiliser.

Chilli fruit may be infested with fruit fly larvae

My chilli fruit rot when they ripen. What is wrong?

Francis Wee

Check the rotten fruit for wet spots with puncture marks on the surface. If there are any such spots, your chilli fruit have been attacked by fruit flies. The adults lay eggs, and the young that hatch will burrow and damage the developing fruit. The plant will abort infested fruit.

To reduce damage by fruit flies, you can construct a fruit fly trap – there are numerous reference videos online. To attract the flies, you will need to include fruit fly pheromones, which are commonly sold in nurseries.

Remove and dispose of infested fruit. Consider growing your chilli plant in an enclosure with fine white netting to deter insects.

Protect chilli plant from rain, check for sap-sucking insects

Grow the chilli plant in an enclosure with fine white netting to deter insects. PHOTOS: FRANCIS WEE, ALLAN TEE

My chilli plant is shedding leaves and there are numerous ants on it. The plant is on my balcony and receives ample sunlight.

Allan Tee

Chilli plants may shed leaves if they suffer from moisture stress. If your plant is exposed to the elements, it must be protected from rain, lest the root zone become waterlogged. As the pot is small, your plant may also dry out quickly during hot weather. You may want to move the plant to a slightly larger pot with greater soil volume, which can retain more water.

As for the ants, check your plant for aphids, mealy bugs, scale insects and whiteflies. These sap-sucking plants excrete honeydew, a sweet fluid which can attract ants. Pests can weaken your plant over time. Apply pesticides such as summer oil, castile soap solution or matrine to control their population.

Repot moth orchid in charcoal chips

In the lowland tropics, most epiphytic orchids need to be grown in charcoal. PHOTO: JINYEN YAP

I bought this white orchid from Gardens by the Bay about a year ago. Every time it grows a new shoot, the shoot eventually turns black and dies. Small white shoots seem to be growing constantly at the root area, but new leaves have been falling. The orchid is in a closed pot with its original ball pellets and moss mixture. The moss is kept damp and away from direct sunlight.

Jinyen Yap

The orchid looks like a moth orchid hybrid (phalaenopsis), which thrives in filtered sunlight. A lack of light can weaken the plant and make it prone to pests and diseases. A shaded site will also reduce the rate of evaporation from the root zone.

In the wet and humid lowland tropics, most epiphytic orchids need to be grown in charcoal. You should remove the sphagnum moss from the roots of your orchid and pot the plant in broken charcoal chips, each of which should range from 2 to 3 cm in size. This aerated growing medium will help the roots dry out and prevent rotting. Water the plant whenever the root zone dries out.

  • 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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