Soil Conditioner – designed to mix in with Perth’s sandy soil to create healthy soil and plant growth. Mushroom Compost – designed to mix in with Perth’s sandy soil to create healthy soil and plant growth. Soil Solver – is a natural clay mineral which turns sand into a fertile loam soil, full of mineral rich silts. It transforms sand into a reliable garden soil that permanently holds onto more water and nutrients, and you only need to add it once! It comes in a 22.5 kg bag. For existing beds, pour 5 kgs per sqm over the surface of the bed, water, and mix with a hand held hoe. Alternate between watering and mixing. Add another 3 to 5kgs and repeat the mixing.