Choose the right pot for your plants

SINGAPORE – The use of containers, commonly called flower pots, to grow plants is part and parcel of gardening. Flower pots are often used in high-rise apartment gardening and they offer gardeners flexibility, as one can manage soil type and quality according to the plants’ needs and move them around. Since a flower pot has a finite size, it can be used to contain the root system of a plant and this can help to manage the plant’s overall size.

Flower pots that are used to grow plants should have drainage holes at the base, as these allow excess water to drain out from the root zone. This is necessary to prevent waterlogging, which can cause roots to suffocate, rot and die. Drainage holes can be covered with a plastic mesh and should not be totally plugged. This minimises the loss of growing media over time and still allows the drainage of excess water.

There is a wide range of flower pots made of different materials, such as plastic, ceramic and terracotta.

Plastic pots are affordable and the most commonly available. They are lightweight and, due to their impervious nature, can help retain moisture for longer periods in the root zone as water cannot evaporate from the sides of the pot. Plastic flower pots are ideal for growing plants that like a moist root zone, such as seedlings and foliage plants.

Do note that plastic pots may degrade with time when exposed to direct sunlight. Manufacturers may incorporate additives into the plastic material to make them more durable under such conditions. The surfaces of plastic flower pots can also be scratched easily through rough cleaning and handling, and accidents. This can adversely affect their look.

Ceramic flower pots are another popular pot type. They have a glazed surface, a glassy coating that makes them impermeable to liquids. This treatment gives ceramic pots a property similar to plastic ones: Moisture from the growing media will not be lost through the sides of the pot.

Ceramic flower pots can be highly decorative and will usually be more costly than plastic pots. They are rather heavy, but their weight can be used to the gardener’s advantage: Plants grown in them do not topple easily, especially when placed in an exposed and windy area. Flower pots that are made of ceramic tend to be more scratch-proof, but must be handled with care as they can break if dropped.

The third type of flower pot material is terracotta. This pot type is unlike the previous two: The material is porous and allows growing media moisture to be lost through the sides. Plants grown in such pots will, therefore, require more frequent watering.

Like ceramic flower pots, terracotta flower pots can also be heavy. They are generally scratch-proof but should be handled with care to avoid breaking them. Terracotta pots are popular among gardeners who grow Mediterranean herbs like rosemary and lavender, and xeric plants like cacti and succulents.

The reddish-brown clay material lends such flower pots an appealing rustic appearance. Due to the material’s porosity, moisture is drawn outwards from the growing media to the exterior surface, permitting algae growth to occur in a humid garden environment. Fertiliser salts can also be deposited on the pot’s exterior, leading to the appearance of a white, powdery layer.

Tips for container gardening

Successful container gardening requires selecting a pot of a suitable size for one’s plants. As a rule of thumb, the optimal flower pot size is 5cm to 10cm larger in diameter than the plant’s current container or root ball.

It is vital to avoid using a flower pot that is oversized, as it will contain a large amount of growing media which can hold too much water. A small plant will not be able to utilise the water for its needs and the moist root zone can be detrimental to the health of your plant.

Conversely, a plant grown in a small pot may become pot-bound, in which all its roots have filled the pot, and it will require more frequent watering as the water reserve will be limited and quickly exhausted.

Another factor in selecting a good pot for your plant is to find one with slanted or straight sides for easy repotting in the future. Flower pots with slanted sides where the widest point is at the top rim is most ideal: The root ball easily slides upwards and outwards with minimal resistance.

Avoid pots with bulging sides, where the middle part of the pot is wider than the top opening, as the removal of the root ball be hindered by the narrower top rim when it comes time to repot. You will most likely have to break the pot or severely damage the plant’s roots to get it out.

You can check out plant pots and other gardening essentials at the Singapore Garden Festival’s MarketPlace. The festival is on at Gardens by the Bay from July 4 to 12, and tickets are available from go.gov.sg/sgf. Admission to the MarketPlace is free.