Allotment Vegetable Growing
Monday 20 May 2013
Vegetable, Fruit & Herb Gardening
Improving Clay Soils by Clodagh & Dick Handscombe
Clodagh & Dick Handscombe are active gardeners and authors living in Spain. They have written a trilogy of books - Your garden in Spain, Growing healthy fruit in Spain and Growing healthy vegetables in Spain.
As well as contributing to the Allotment Chat forums they have their own web site called and about Gardening in Spain
Ever since we became involved in growing vegetables when five years old with parents and grandparents improving clay soils in Ireland and the UK has been a priority. And the challenge followed us to Spain. Here our raw red clay soil was used until fifty years by villagers to make home made bricks!
The top soil being a combination of particles from the erosion of the side of the mountainside that we live on - 400 metres up , ten kilometres from the Mediterranean beaches -, natural humus from wild plants before we cultivated it , and the red earth particles carried from north Africa for millions of years by southern gales that fall as 'red' rain. Called that as the cars are that colour when they dry!
So we need to improve the clay soil in order to be able to grow our organic vegetables and fruit ;
The table below illustrates what we mix into the raw clay soil to improve it:
The bulk ingredients are blended in by digging or rotovating down to a depth of twenty to thirty centimetres for vegetables and fifty for fruit trees or by tipping backwards and forwards between two 20 litre plastic builders/gardeners buckets when preparing soil/compost mixes for containers.
* Two nearby towns have Eco-parks that compost garden rubbish from municipal parks and professional gardeners and seaweed washed upon to beaches by storms. The sieved compost can be purchased with or without seaweed at only 3 euros a hundred kilos.
**We add comfrey leaves, rabbit and chicken manures to our five pallet built compost bins as accelerators and enrichments. We also have an experimental mini worm composter to produce compost to mix into containers and window boxes used for mini vegetable growing.
***We mulch rows of raspberries with comfrey leaves and grass cuttings.
The rows of comfrey we top dress with well composted chicken manure once as year. Comfrey leaves are wrapped round seed potatoes and mixed into soil where beans and peas will be grown.
****Naturally if we had a sandy soils we would leave out the addition of course sand, grit or ground lava.
With such a mix plants have an ample supply of nutrients and moisture to support steady healthy plant growth. Only hungry fruit vegetable plants such as tomatoes peppers and squashes, and fruit trees (after a couple of years) are given supplementary feeds of a liquid comfrey feed.
Nearby Spaniards who have abandoned the annual improvement of soil with donkey, mule, horse, rabbit and sheep/goat manure during the past thirty years now use excessive amounts of water and inorganic fertilizers to grow vegetables for the local market. Not only are they often rather watery and lacking taste but the forced growth is susceptible to insect and fungal attacks in the hot and humid Spanish spring and summer climates..
Although ecological/biological solutions as well as organic chemical solutions to such problems are now available so we avoid using even these if possible by growing naturally rather than by forcing. By the way we only grow vegetables for personal consumption ad not for shows - a phenomenon that is unknown here in Spain.
As said in our books feed the soil and not the plants for naturally tasty healthy plants.
Article © Clodagh and Dick Handscombe May 2007
Gardening Help: 10 Great Gardening Tips and Ideas
The Essential Allotment Guide
All you need to know!