Improving Your Spanish Soils

By Clodagh and Dick active gardeners and authors living in Spain for 20 years.

One of the big challenges of gardening in Spain is the improvement of poor soils before planting flowering plants, non flowering evergreens, vegetables, and fruit trees bushes and plants so that they can be grown healthily without the need for excessive amounts of water and unnatural levels of artificial fertilizers.

Based on our hundred years of being involved in organic gardening including our combined forty years in Spain we would now add the following to the frequently found heavy red clay soils when preparing a new flower bed , metre square areas for planting fruit trees, a new vegetable plot, or filling raised beds or containers in preparation for fruit trees or vegetables.

We mix the bulk ingredients 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 buckets when preparing soil/compost mixes for containers.



To lighten the soil, make it more workable, improve it’s water holding capacity and at time make it more free draining. Mix in two to three 20 litre builders buckets of homemade, Eco-park or bagged compost per square metre of soil.
To further improve soil fertility. Mix in a bucket of composted or dried bagged manure per square metre.
To further improve it’s water holding capacity during hot dry weather. Mix in a little TerraCottem soil improving gel (
To further ensure it will be free draining and not become waterlogged. Mix in 5 to 10% course sand, grit or ground lava.
To make minor increases in soil acidity and kill off lurking fungal spores. Dust surface with sulphur powder
To further kill off fungal spores plus young slugs Sprinkle surface with ground neem kernels ( for instance).
In areas for roses and asparagus for instance Mulch with partially composted Seaweed.
For plants preferring acid soil such as camellias, blue hydrangeas, rock roses and strawberries. Mix in compost made from pine needles, a bag of acidic compost or/and natural sulphur powder.

Naturally for sandy soils we would leave out the addition of course sand, grit or ground lava.

With such a mix plants will have an ample supply of nutrients and moisture to support a steady healthy growth. Only hungry fruit vegetable plants such as tomatoes peppers and squashes, and fruit trees will need supplementary feeds.

If you decide to not improve your soil before planting but to use regular quick acting chemical feeds you will run the danger of stimulating fast weak fleshy growth susceptible to insect and fungal attacks in the Spanish spring and summer climates..

Ecological/ecological solutions as well as inorganic chemical solutions to such problems are now available but why not avoid using even these if possible.

A useful alternative mix for containers especially if living in an apartment is 80% of a good peat/earth based compost plus 10% of bagged worm or dried animal manure. Each is available in good garden centres or agricultural cooperatives.

Some plants such as palms, yuccas, cordylines, succulents and cacti require a more open gritty/sandy soil. For these we suggest you double or treble the amounts of course sand, grit or ground lava mentioned above.

As said in our books feed the soil and not the plants for naturally healthy plants.

*Authors of the trilogy of books Your garden in Spain, Growing healthy fruit in Spain and Growing healthy vegetables in Spain.

© Clodagh and Dick Handscombe April 2007.