The Essential Nutrients in a Good Quality Topsoil

The mark of a top quality topsoil is the correct ratio of sand, silt and clay. Soil types vary more than most people realise, even between garden beds at the same property. A combination of 60% sand, 15% clay and 25% silt results in a nutrient-rich product for mixing with garden soil or creating the ideal growing environment in planters.

At this ratio, topsoil provides the ground with four essential nutrients:

• Magnesium
• Nitrogen
• Potassium
• Phosphorous

With these nutrients, gardens have everything they need to house a sustainable, healthy and balanced soil for turf, plant and vegetable growth.

Magnesium

Chlorophyll, the essential green pigment in plants that enables photosynthesis, has magnesium as one of its constituents. Yellow veins on older leaves of a plant indicate a magnesium deficiency, something that a premium quality topsoil helps to restore.

Nitrogen

Leaves and stems rely heavily on nitrogen as a main growth nutrient. A deficiency stunts plant growth and leaves the older leaves looking yellow throughout. Too much nitrogen results in disproportionate leaf growth, usually at the expense of flowers and other parts of the plant. A balanced topsoil provides exactly the right amount of nitrogen.

Potassium

Potassium aids photosynthesis and helps in developing fruit or flowers. Yellow or dead marginal leaf tissue indicates a potassium deficiency.

Phosphorous

Phosphorous, an essential constituent for healthy plant growth and development, is the fourth important nutrient in a premium topsoil. Stunted roots and leaves with either a dark green or a purple discolouration indicate a lack of phosphorous in the soil.

The importance of a balanced topsoil

Avoid using soil from elsewhere in the garden. A balanced product from a reputable topsoil supplier contains organic matter derived from decomposed plants, something a more traditional garden soil lacks. This organic matter contains the four important nutrients needed to balance the planting environment and promotes drainage during wet seasons.

• No two topsoil types are the same. A product of good quality, in addition to important nutrients, also provides ample air, water and oxygen.

• Add fresh topsoil annually to compensate for lost nutrients absorbed by plants, especially in areas with annual flowers or those put aside for vegetables.

• A good soil has an easy-to-till quality that stirs up compacted nutrients ahead of introducing bulbs, seed, plants or vegetables into the ground.