SINGAPORE – I often joke that Singapore has four seasons: the hot, hotter, wet and wetter periods. With the end of the year coming, people can expect the arrival of the rainy north-east monsoon season.
For many gardeners who grow edible plants outdoors, this can be a challenging time. Many such plants fare poorly in the rain. Heavy rainfall can injure plants, waterlogging can oversaturate soil and remove the oxygen roots need for respiration, and the lack of sunlight inhibits growth.
All this can lead to poor plant health. Worse, certain pests, such as snails and slugs, appear more frequently in wet weather and will devour the plants.
One approach to reduce rain damage and prevent pests from reaching your plants is to set up a netted tent. This enclosure is typically made of white plastic netting. White is preferred as it allows more sunlight to pass through than other colours. Use galvanised steel poles as supporting structures for durability.
A rectangular enclosure will be the easiest to build and is suitable for allotment garden plots, as the longer side can serve as an opening for gardeners to access the plants. Some gardeners also use a bamboo pole to weigh down the netting and close off the tent as needed.
For the other three sides, bury the lower part of the netting in the soil to deny entry to pests that may eat your crops.
To protect the enclosure from rain, the top can be covered with a clear plastic sheet so the plants can still get sunlight. Pull it taut so that water does not pool on the surface.
Choose pots with rims to prevent pests from accessing plants.
PHOTO: WILSON WONG
Gardeners who grow their plants in pots also need to find the right type of container. The overhanging rims of certain pots – designed for easy lifting and movement – can act as a barrier to keep out snails, which get wedged underneath the rim.
Many edible plants are grown in raised garden beds with well-draining soil, but these may not dry out sufficiently after torrential rain. Consider growing edible plants that tolerate wet feet, especially if you are not building rain shelters.
Kangkung is a fast-growing vegetable that can grow in wet soil.
PHOTO: WILSON WONG
The most reliable edible plant to grow during the wet season is a familiar leafy vegetable: water spinach (Ipomoea aquatica), locally known as kangkung.
Kangkung grows from seeds in wet climates and has hollow stems that allow the plant to float on water. These grow quickly and can be kept close to one another.
It is a “cut and come again” crop. The top part of the plant can be cut, leaving a few nodes left on the remaining stem for new growth to regenerate from.
Water celery is a traditional leafy vegetable with a creeping growth habit.
PHOTO: WILSON WONG
Another traditional vegetable is water celery (Oenanthe javanica), known as daun selom in Malay. It has a creeping growth habit and hollow stems. Its young leaves and stems can be eaten raw or cooked. Plants can be started from materials bought from markets in Singapore.
The leaves of the Rice Paddy Herb emit a delightful scent.
PHOTO: WILSON WONG
The Rice Paddy Herb (Limnophila aromatica), also available for sale at markets, is similarly undeterred by wet feet and can be propagated the same way as water celery. It has a notable citrus-cumin scent and flavour, and is used in Vietnamese and Thai cuisines when cooking fish.
Pandan is a highly versatile plant that can thrive in both wet and dry soil.
PHOTO: WILSON WONG
Another common and useful plant for waterlogged locations is the fragrant pandan (Pandanus amaryllifolius), often grown at the edges of ponds or inside a water body. It can be propagated from cuttings with roots, or purchased in pots from retail nurseries.
These water-loving edible plants still need to be grown in a sunny spot and do not thrive in the shade. They can be grown during the drier season in Singapore, but will require deeper and more frequent watering.
Plant Parenting is a series about houseplant care and other gardening essentials. Have a gardening topic you are interested in? Write in to
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Dr Wilson Wong is an NParks-certified practising horticulturist and parks manager. 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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