Cushion moss too dried up to be revived

I planted moss in an open terrarium (pictured) and sprayed it with water every other day. However, I once forgot to water it for four days. That caused the moss to dry up. I have resumed watering regularly, but the moss remains dry. What do I do?

Soh Kai Han

The moss is likely to be the Cushion moss, which is botanically known as Leucobryum glaucum.

Once the moss dries up and turns brown, there is little chance of reviving it.

This moss prefers to be grown in a cooler environment, such as in an air-conditioned office with local tropical conditions.

It needs to be given good filtered sunlight and kept constantly moist. It should never be allowed to dry out completely.

The environment should be kept humid, but there must be some air circulation. The terrarium should not be totally covered.

With an open terrarium, moisture will evaporate over time, so it is necessary to keep track of when to water it.

If you are away for a long period of time, close the open terrarium partially to reduce the rate of evaporation and ask someone to help water the terrarium.

Tip: Rex Begonia Vine a climber with attractive leaves

Despite its name, the Rex Begonia Vine is not related to begonias. It is a member of the grape family.

This climber has attractive leaves that can rival those of a begonia's. Its dark green leaves are shaped like shields and have patches of silver. However, when the leaves are turned over, their red undersides are revealed.

You can train this plant to climb and grow on trellises. Unlike many other climbers, the Rex Begonia Vine can be grown in a semi-shaded area and prefers moist and well-draining soil to thrive.

Whiteflies suck on sap of lime plant

My lime plant was growing well and blooming before it became infested with white flying insects. I tried spraying the plant with white oil, but it has no effect on the insects. What are the insects and how do I get rid of them?

Gan Sing Hai

The pest is the whitefly, a type of sap- sucking insect. Whiteflies may appear if plants are stressed due to sub-optimal growing conditions.

The lime plant grows best in a sunny area. If you are growing it in a shaded location, give it at least four hours of direct sunlight daily.

For now, the most environment- friendly way to manage whiteflies is to use a strong water jet to wash them off the plant.Repeat the treatment if the infestation returns.

You can also use organic pesticides such as neem or summer oil, which suffocate the insects. The oils need to be sprayed regularly so that all pests and their young are eradicated.

Carica papaya is edible

What is this plant (pictured) and can its fruit be eaten?

Jillian Toh

The plant is the golden variety of the edible papaya. Its botanical name is Carica papaya.

It has red petioles - a stalk that joins a leaf to a stem - that stand out against its yellow-green foliage. The edible fruitare best harvested after they ripen naturally on the plant.

Protect the ripening fruit from animals by wrapping them with a wire mesh. The Carica papaya plant can also be grown in a garden for its ornamental value.

Water lily needs more sunlight

I bought a potted water lily from a nursery here and moved it into a larger container. The plant received four hours of afternoon sun every day. After a week of buying the plant, I buried a fertiliser pellet meant for lotuses and water lilies. The plant grew well, with new leaves sprouting for the first two weeks. However, the leaves started to rot. Why did this happen?

Leong Tuck Sum

Water lilies are sun-loving plants and need more than four hours of direct sunlight a day to be healthy. So, the rotting of leaves could be due to lack of sunlight.

Another reason for the rot could be that the plant is buried too deep in your new pot. The crown of the water lily must never be buried too deeply in the muddy substrate as this will cause it to rot.

Finally, ensure the fertiliser pellets are not applied too near the crown of the plant. You should use less than what is recommended on the product label as excessive fertiliser can burn and injure plants.

•Answers by Dr Wilson Wong, a certified practising horticulturist and founder of Green Culture Singapore (www.greenculturesg.com). He is also an NParks-certified park manager.

•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.