There are many aspects of gardening that we, even those with many years of experience, tend to take for granted. Selecting the right kind of plant pot for the job in hand is one of them.
It is wonderful to know that the number of newcomers to gardening is increasing by the day but judging from the questions they submit, they are more than a little puzzled about the pros and cons of the various plant pots and containers currently available in the market as well as what can be grown in recycled containers.
Plastic plant pots versus traditional, unadorned clay ones
Plastic plant pots in various sizes and shapes have flooded into the country in the recent years and many gardeners are opting to use them. Often more expensive than their traditional clay counterparts, plastic pots are light to handle, easy to clean and have clearly defined drainage holes in the base. Being lightweight is their main advantage, especially if they are to be used in rooftop gardens where, unless the roof was architecturally designed to be load bearing, every bit of weight must be taken into account. A seriously overloaded roof could, quite conceivably, be damaged by the tremendous weight of a huge number of pots, the soil they contain and the incredible weight when soil is wet.
The right pot or container is essential to your success and your ability to care for your plant properly
The problem with these light-weight plastic pots is that they offer no resistance to sunlight and heat: the soil in them dries out rapidly and plant roots too become overly hot and dry out, unless they are watered at least once, perhaps even twice, a day when temperatures are high.
On the other hand, traditional clay plant pots are heavy and difficult to move around, particularly if these are full of soil and plants, but these thick clay pots work hard to retain moisture and keep plant roots cool. Plants in clay pots need far less water than the same plants grown in plastic ones.
I would recommend clay pots over plastic ones every time.
Naturally small plants usually — although there are always exceptions to general rules — have small, shallow, root systems as do slow growing species such as baby cacti. These small plants are perfectly comfortable in small plant pots. It is a waste of space, plus, soil/compost, to put a small plant into a huge pot. If, however, once a small plant has a growing spree and becomes too large for its existing small pot, then it should be, very carefully, transplanted into a pot that is big enough to take all its roots with ease and still leave some room for further growth. Low-growing plants are generally quite comfortable in shallow pots: a plant growing no more than four inches tall for example, being happy in a pot which is four to five inches deep. On the other hand, a plant growing to a height of perhaps two feet requires a pot that is at least 12 to 18 inches tall to allow for its longer root system and to create the harmonious balance without which it could easily fall over. As tall-growing plants usually have long/deep roots, these require deeper pots than small, shallow-rooted plants. If in doubt, study plant height versus pot depth and go for equal balance.
Plant pots must have drainage holes in their base
These holes allow excess water to drain away and hence prevent water-logging of soil and plant roots. Water-logged soil/plant roots encourage disease and is a common cause of plant death. Plant pots can be stood on/in saucers, trays and other leak-proof containers to catch any excess water as it drains: this excess water must be cleared away as soon as it appears in order to avoid spillage problems and insect pests.
Usually two to four inches in depth, filled almost but not quite to the top, these are used for germinating seeds. Shallow plant pots can also be used for this purpose as can a whole host of other items e.g. fast food containers, as long as a suitable number of drainage holes have been made in the base. Seed trays are solely used for germinating seeds as they are too shallow for the long-term growing of most plants.
Alternatives to plant pots
There are many items that can be recycled and used to grow plants in. Yoghurt cartons, tins, cut-in-half plastic bottles, milk and juice cartons cut in half, each with drainage holes made in the base, can all be utilised to good effect for seed germination, for rooting cuttings and for growing plants. Wooden vegetable/fruit crates lined with a few layers of newspaper and then filled with soil/compost make excellent flower, herb and vegetable boxes in which to grow lots of produce in a relatively small space or on rooftops. The same goes for polystyrene fish boxes, other extra strong boxes, discarded baskets, half-barrels/drums, heavy plastic crates and, in fact, anything at all which is capable of holding soil/compost and in which provision for drainage can be made.
More basic tips and information to come, on and off, in future weeks.
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Published in Dawn, EOS, January 14th, 2018