The South family considered that hand thrown pots were superior to the machine made and plastic competitors with regard to porosity and frost resistance. Brian Yates has recently posted an article on the website of the British National Carnation Society debating the merits of the various types of pot and which is reproduced here with his permission.
There has been much debate about the plant pot. Should you use a plastic pot or a clay pot, what size pot should you use, is it frost proof, what about drainage, is the chosen pot right for me. We look for guidance from our elders, fellow members and advertisements, but above all we see what the nurseryman is using and if the garden centre has supplied the plant in a plastic pot then it should be the right one or type to use, after all they should know because they are the experts, or are they?.
We must begin by looking at the cold hard facts of the hard nosed business man who runs and owns the large nurseries that supply the garden centre trade and see how his mind works. He has to maximise profits with as little outlay as possible, and with the help of heated glass houses that are equipped with growing lights and massive fans for air distribution, he can grow seedlings and plantlets on a colossal scale. As his seeds and plants grow he has to pot them up for the retail market and once again he needs to use a pot that is not so much durable but expendable so he needs to choose a cheap, light container to transport his plants to the garden centre, hence you will see 99% of plants on offer at a garden centre growing in a plastic pot. This container is really like a carrier bag picked up at the supermarket for carrying your shopping home in; once you step indoors you unpack the bag and place your purchases in the refrigerator or vegetable rack. Just leave your potatoes in the plastic bag and within a week you will see the potato sprouting. It is the same with the plastic pot that your plants are sold in from the garden centre. It is a means of packaging that is all; it is up to you to place your plant into a more suitable container. I am not saying that plastic is not right for a plant because in some cases it is just the right environment for the plant, but with other plants it is not so favourable.
Carnations and all Dianthus have specific needs and to obtain the best results from our plants we need to observe and satisfy their needs. We all know that there is a need for free drainage, for to grow in constant wet conditions will only rot the root ball and allow disease to creep into the plant, to try and grow in wet and sodden clay is fatal. Protection from extreme cold is also necessary for to allow your plants to freeze will culminate in the loss of the plant. In the summer when the plants are growing and in full bloom and we are enjoying a better climate then the need for regular watering is vital but we must still ensure that the plant is not waterlogged. Winter and the plants only need the occasional water and are best kept on the dry side. So how do we gratify our plants needs to keep them growing happily. I use a clay pot for my carnations as these are most suited for growing carnations, you may ask why.
It is porous and will dry out regularly thus giving the plant a good growing environment, it acts as an insulator in winter against freezing and a cooling system in summer due to it being thicker and porous, it is heavy so will not blow over easily, watering is easily controlled by the use of a stick that you tap against the side of the pot daily and with the change in the sound given off you will soon get used to knowing when the plants needs water..
Yes there are lots of disadvantages in using a clay pot, it is easily broken, it is heavy in comparison to a plastic pot, it tends to discolour on its outside due to fungus growth, with the advent of the population now taking holidays abroad we rely heavily on friends and neighbours to keep our treasures watered and the clay pot dries out quickly.
Yet when we are sunning ourselves in Spain, Italy, or Turkey look around and see what type of container they are using, nine times out of ten it is a clay pot.
Years ago when I was a lad and that is too many years than I wish to remember, clay pots were sized pots thus,
Thumbs or Nineties are 1 inches diameter across the top and 2 inches deep.
Thimbles or Seventy Two's are (72's) 2 ½ inches
Sixties (60's) are 3 inches
Forty Eights (48's) are 4 ½ inches
Thirty Two's (32's) are 6 inches.
Twenty Fours (24's) are 8 ½ inches
Sixteen's (16's) are 9 ½ inches.
Twelve's (12's) are 11 inches.
Eights (8's) are 12 inches.
Sixes (6's) are 13 inches.
Fours (4's) are 15 inches.
Twos (2's) are 18 inches.
The larger size pots like the sixes, fours, and two's are normally not so deep and are ideal for rooting cuttings.
All of the above sizes are for the clay pot
Today with plastic pots, we tend to size pots by centimetre (cm) or litres thus,
Six Packs are 7.5cm x6.5cm and supplied as a moulded together pack of six.
Nine Packs are 5cm x 6cm and supplied as a moulded together pack of 9.
Twelve Packs are 5cm x 5cm and sold as a moulded together pack of 12.
1 Litre is 13 cm Diameter wide at the top and 10cm deep
1.5 Litre is 15cm x 12cm.
2 Litre is 17cm x 13cm
3 Litre is 19cm x 14.5cm.
5 Litre is 22cm x 18cm.
7.5 Litre is 26cm x 20cm.
10 Litre is 28cm x 23cm.
15 Litre is 32cm x26cm.
20 Litre is 37cm x 27.5cm.
25 Litre is 40cm x 28cm.
30 Litre is 40cm x 33cm.
There is nothing wrong with a plastic pot, it is durable, easy to clean and hygienic and fungus growth is non existent. Drainage is good due to masses of small holes in the base and as long as the pot is crocked well and kept off the ground then it is well suited to growing plants. Cold winter days are compensated by a small heater and a closed green house door. Price is much the same these days for a plastic pot and a clay pot so it just down to personal preference, and of course you have the choice of colour for your plastic pot.
Clay pots of today are normally sized by the diameter across the top of the pot thus, 2 inch, 3 inch, 4 inch, 5 inch, 6 inch and so on, and are normally made in Italy where they are fired at a lower temperature and arrive damp. If they had been fired at a higher temperature then fungal growth would be minimal and frost damage would be non existent. There has to be a niche for some enterprising person in Britain to make injection moulded clay pots as cheap if not cheaper than they can import them from Italy.
The first commercially successful design for a biodegradable pot was the Root-o-pot by Jiffy pots and composed of 75% sphagnum peat and 25% wood pulp. Launched in America in the mid 1959s, these were introduced to Britain a few years later. These Jiffy pots are now widely used by commercial and amateur grower alike for rooting plants that can be planted out with no root disturbance.
These days we have pots made from coconut fibre, wood, slate, even steel.
The greenhouse is the last link, and in 1833 plate glass was invented and although initially heavily taxed, people soon overcome this problem by trading for plate glass on the black market so greenhouses began to spring up all over Britain and all kinds of exotic plants were brought back from far off lands. Today there is hardly a garden without a greenhouse.
White Hart Lane Potteries, London N17 were owned by Samuel South's and Sons who first began making pots for the Nurserymen and Market Growers in 1868 and it normal for them to receive an order for some half a million pots, all hand thrown of course, then with the coming of the 20th century we have full mechanisation and in 1907 clay extracting machinery was introduced and larger potteries like Messr's Sankey moved into machine production, and that sealed the fate of many small potteries including Samuel South & Sons which closed in 1960.
Ironically, things have now come full circle and we see large clay pots adorning patios, glazed pots of all colours, and clay strawberry planters.
All of these facts are taken from Ken Barker's book South From Barley. It is a fascinating book on the history of the clay pot and the history of Samuel South Pottery and I have two copies, one of which I intend to keep for myself and the other is for the first member to post a comment on this article within the forum. Be it a favourable comment or not.
For information on clay pots you can go to www.samuelsouth.btinternet.co.uk