Improving soils

very sandy soils

Very sandy soils are often water repellent. Dry hydrophobic soils can be improved by initially applying a wetting agent. You can use a commercial product, or just soapy water, grey water irrigation also makes soils less water repellent. Another recipe is to dissolve 2 tablespoons of powdered agar agar in 2 cups of hot water to make a runny paste. Stir 250 ml of this paste into 5 l of water and water on the garden.All these measures are only short term solutions, but necessary to get you started, once your soil is water repellent.To improve your sandy soil add plenty of organic matter as listed above. On extremely sandy soil, layer up to 20 cm of this, mulch it, keep it moist for 2 or 3 weeks and then start planting.Since sandy soil is poor in nutrients add ground rock dust. This contains trace elements which plants need only in really small amounts. Without it, however, plants may be stunted, less productive and disease prone. Microbes love it and they convert it into a form plants can absorb.Mulch your beds to keep them cool and reduce evaporation. Keep the beds reasonably moist but don’t over irrigate. You need to find the sweet spot between not leaching out the nutrients and not getting back to dry, water repellent soil.You will get an instant effect and can start planting. Sandy soil needs an ongoing effort to build structure and maintain fertility, it should always be kept planted. Don’t dig or til your garden deep, rather build a layer of humus over the years. Water retention and nutrient density will improve with every year that you keep on adding organic matter.A mix of seaweed solution and fish emulsion will keep your plants thriving.

very clayey soils

Improving clayey soil isn’t an easy task, nor is it quick. It may take several years before your garden starts thriving. Instead of improving your soil, you can build raised beds.Avoid walking on the soil whenever possible so you don’t compact it.

Perform an immersion/dispersion test: Drop a 6 mm piece of dry soil into a glass of rainwater. Don't move the glass. If the majority of the soil first builds a halo and then disperses into the water in 24 hours your soil will benefit from adding gypsum. You need to use natural gypsum for this and go with the recommendation on the package (about 0.5 to 1 kg/sqm). This can change the soil structure from big clods to a finer texture. Don’t use gypsum if the test comes out negative.An option is to add very sharp sand to loosen up your soil, but never use fine sand, because it turns clay into a concrete like texture.Clayey soil is usually rich in minerals, so it doesn’t need a continuing feed of rock dust like sandy soil does.

In any case add at least 20 cm of organic matter to the entire bed. Plant green manures between your crops and dig them in.

Avoid compacting the soil, never work the soil while it is wet. Do not overwork your soil by excessive tilling. Extensive tillage stimulates microbial activity and the consumption of mass quantities of organic matter ensues. After several years of adding organic matter your clay soil becomes more friable and you have provided a deep root zone for your garden plants, you should consider reducing tillage more and more.