U3A GARDENING GROUP – Local soil types and “Flat Gardening”

Summary notes provided by Bob Cardwell, U3A Gardening Group member,

November 2013 Meeting

We started with a few elementary comments on the geology of the North Downs which lightheartedly were said to be all chalk as shown by some local building sites in Godstone Road in Caterham and the new building on Succumbs Hill.

In fact the more level tops of the Downs which run from the narrow Hog s Back, beyond Guildford through to the coast between Folkstone and Deal are often covered with an acidic strata usually including a layer of clay-with flints . Then below that are three distinct chalk layers. The Upper Chalk which has many flints, the Middle Chalk with fewer flints, and the Lower Chalk or Coombe Rock- grayish and fewer flints. It was pointed out how there had been enough clay for there to have been a clay pit in the Blanchman s site which provided clay for local bricks, and there were many examples locally of how the flints had been used in building, in the past - Forge Cottage in Farleigh Road, and cottages in Farleigh Road, Chapel Road and many small walls incorporate much flint material. Even the newer built Chez Vous uses flints in its décor.

This helps understand why gardens can grow the plants that accept the different subsoils from chalk through to heavy clays. But one does need to establish what one s soils contain to help choose the right plants.

We then went onto talk about shade planting. Shade is described differently by different authorities but the RHS talk of light , partial, moderate, and deep .

Shade is important because all plants need to use Chlorophyll to absorb energy from sunlight. Thus plants that have a large spread of leaves can make the most of any sunlight that reaches them. Grass on the other hand having such a small surface area cannot get much energy and it is why lawns do not succeed in shady areas. Shade can be dry eg close to walls or close into the large central trunk of a tree or wet where soil structure holds the water and/or there is a high water table. Gardeners World magazine have a very useful reference booklet which shows the differing environments and lists the plants that do well in each condition. A good check before buying plants may save some disappointment later where plants are in an unfriendly environment.

The last subject covered the “ Flat Garden ” (what you can and cannot do when living in a flat!) and a long list was shown of the trials and tribulations of gardening in a flat. These are briefly summarized:

1. The Lease - does it allow the attachment of say hanging baskets to the outer structure.

2. Does the structure even allow for attachment as it was shown that all walls of the flat were tile hung.

3.How weight bearing is the balcony? And mention was made of large dustbins used for vegetable growing.

4. What is the drainage on the balcony? where does the rain go and from the watering of plants

5. Saddle pots were enthusiastically described and shown in different state of filling. Praise was given to Croydon Council who make excellent displays along Wellesley Road and outside East Croydon Station where saddle pots straddle the safety railings and give a very colourful display which completely hides the pot.

6. View aspects. One wants to have an attractive display facing into ones flat to enjoy the colours but also wants a display to be seen from out side the building. Sun etc. will pull the plants towards the light and away from the interior of the flat where one wants to view them.

7. Pots on the floor do give a good view when looking down but not sideways on.

8. Pot drainage - where does the water come from - saddles have small vertical pillars with a drain hole at the top and when water reaches the top, flows straight out.

9. Watering - plants will get more sunlight up high, and so warmth, and more wind so will dry more quickly, hence need more regular watering and how do we measure their needs?

10. Them downstairs. One wants to live in harmony with those in the flat below but they will suffer your overwatering and all the leaves as they drop will finish up on their patio or even furniture!!.