"Are you going to Scarborough Fair? Parsley, sage, rosemary and thyme..."

The herbs of this song, together with majoram, oregano and bay, are commonly used to spice up Western dishes. These culinary herbs originate from the Mediterranean region and can be challenging to grow in tropical Singapore.

In their native habitats, many of these herbs grow in sunny areas where the soil is dry, well-drained, and lean in nutrients and alkaline. To grow them successfully, it is necessary to replicate these conditions. On the other hand, basil and mint like to be kept moist and do not tolerate drying out.

Here in Singapore, herbs can be successfully grown in high-rise apartments with sunny growing areas. They prefer a location which receives at least four hours of direct sunlight. There are advantages to growing herbs in high-rise settings: they are given some shade from the intense light rays of the mid-day sun, and protection from excessive water from our heavy rainfall.

These are some additional tips for successful growing of herbs:

1. Give your herb plants space

Grow your herbs in individual pots, and space them out to permit air circulation between plants and to maximise their exposure to sunlight. This will help to reduce the incidences of fungal and bacterial diseases that affect these herbs.

Also, rotate them periodically - once a week, at right angles - to allow all sides of the plant to be directly exposed to sunlight.

2. Select the right growing media

Soil available locally is often clayey, drains poorly and retains too much moisture. You can concoct your own growing media instead. Mix at least two parts of gritty material, such as fine-grade lightweight expanded clay aggregate pellets (commonly called LECA) with one part of mature compost and one part of commercial loamy soil mix.

The large particle size of fine LECA pellets 'opens up' the growing mix, permits excess water to drain away freely and allows the root zone to dry out quickly between each watering.

3. Water them wisely

A soil mix with a large proportion of organic matter, such as compost, will also hold more water. It is important to water your potted herbs thoroughly - pour enough water to see the excess water drain from the base of the pot. Avoid using saucers at the base of the pot.

Depending on the environmental conditions of your growing area, you may need to water your herbs either once or twice daily. Sunnier and windier locations would require more frequent watering.

To know when to water again, stick a chopstick deep into the pot and then pull it out to take a look. Soil that is moist will have bits of the mix sticking to the chopstick, and the chopstick will also feel moist.

You can also use your index finger to feel for moisture below the soil surface. Water again only when this simple soil test indicates that the potting mix is on the slightly dry side.

4. Add the right nutrients

Avoid over-feeding your herbs as this can lead to rapid and tender growth which not only attracts undesirable pests but their flavour as well.

For most herbs, a few pellets of slow-release fertiliser pellets, such as Osmocote, are sufficient to complement a weekly watering and foliar spray of dilute seaweed extract.

With these useful tips, you too can grow healthy herbs in your own high-rise haven.

By Wilson Wong

The components of potting mixture for growing herbs. Clockwise from top: commercial packed loamy soil, fine-grade Lightweight Expanded Clay Aggregate (LECA) pellets and mature compost. The LECA pellets help to enhance the drainage of loamy soil.

Take extra care when giving water to moisture-sensitive herbs. Use your index finger or a chopstick to check for moisture inside the pot, and water thoroughly whenever the soil feels a little dry.