Only slightly more pricey are rigid plastic pots which come in a huge range of sizes and shapes. Typically, they have lots of drainage holes, and both heat and cool quickly, so essential micro-organisms are not easily damaged, even when the pots are in sunny locations. The small sizes are especially convenient for seeds, seedlings and annuals. But as petroleum products, they are not environmentally friendly. And they are utilitarian rather than aesthetic. This is one reason why they are so often concealed inside so-called “cachepots”.
Unglazed terracotta containers are a step up. Visually appealing, they both look and are natural, and for those who like such ornamentation, can be bought with raised decorative patterns. But they do tend to break easily, especially during the tricky process of re-potting, so avoid large sizes. And they are porous, which means that they draw moisture from the potting mix, and consequently dry out more quickly. Evaporation is a real issue.
My preference, and that of most people, is for glazed ceramic pots. They are much stronger and have the important advantage of retaining moisture better than unglazed terracotta containers. Stacked high in most garden centers, the commonest type here in Phuket is khaki-coloured, with a rudimentary etched pattern. Personally I prefer plain pots with a dark brown matt finish. Prices vary from about B120 to B400 for gigantic ones.
On the other hand you may feel it worth expending a few more pennies on pots fired in a range of colourful and glossy glazes ‒ of which the blue ones are perhaps the most aesthetically appealing. They are considerably more expensive, but look elegant, especially indoors. Personally I avoid ceramic containers with garish designs: they threaten to upstage the flowers.
Rectangular concrete containers are elegantly slim and modernist. They are extremely solid, usually come in a muted and attractive shade of grey, and will not topple over in high winds. They can be purchased in much larger sizes too, so they are suitable for large shrubs and even small trees such as palms. Self-stacking, modular concrete planters are also available on the market. One drawback: they contain lime, which can be toxic to plants such as azaleas, heathers and hydrangeas. So wash them thoroughly before use.
Stores such as Index, or Home Pro and trendy nurseries may offer plastic or resin “faux” versions of these containers These realistically simulate textured concrete without possessing its heaviness. If money is no object, you might even consider high-grade, imported stainless steel. Such containers are tarnish-proof and indestructible. Personally I would consider wood only for “cachepots”, since the material deteriorates quickly in Phuket’s humid climate.
You need not be limited to circular or square shapes. Troughs are more suitable for narrow patios and balconies, along window sills, or lined up at the base of a wall. In general and because they hold less soil, they are best suited to smaller plants such as bulbs, annuals and herbs.
Two things are worth bearing in mind. Check to make sure your pots or troughs have a hole in the bottom ‒ unless you are choosing a watery home for a lotus or a water lily. Plants require a balance between water retention and good drainage. Saturated by moisture, most will literally drown, or suffer root rot. Secondly, use a waterproof saucer or platen under each container. It will prevent any staining of your precious “sailang” or tiling, and will offer a rough pointer when the soil in your pot is getting dry. Plastic saucers, if you can find them, have certain advantages. Not only are they cheaper than ceramic ones, their slippery bases allow heavy pots to be easily moved around.
Since there is inevitably not much soil in a single pot, it needs to be of good quality. And as I know to my cost, most soil tends to compact when constantly watered, especially if it contains clay. So it is better to mix one part of ordinary loam with one part compost [the stuff in white bags] or one part of coconut husk or coconut fibre. Silica-loving cacti and succulents will need a dash of sand as well. Such potting mixtures retain more water, and, being both friable and porous, will allow the roots some freedom to expand in their new environment. A proprietary fertiliser can be applied at regular intervals (15-15-15 is OK), but it is important not to overfeed, especially when the soil is dry. Over-feeding and over-watering are anathema to most pot plants.
Don’t neglect them, but equally, don’t kill them with kindness.
Dr Patrick Campbell can be contacted at his home Camelot, located at 59/84 Soi Saiyuan 13; Rawai; Phuket 83130. Tel:66 076613227 (landline), 065-5012326 or 085-7827551 (mobile). His book The Tropic Gardener, an indispensable guide to plants and their cultivation in Thailand, is available from Seng Ho bookshop in Phuket Town or Delish in Rawai, or arrange a copy to be delivered by emailing him at email@example.com