Silica additives

It is essential that silica (SiO2) is applied as an additive. Silica cannot be included in concentrated nutrient formulations at meaningful levels. This is because stable silica solutions are by nature highly alkaline.

Silica must be used throughout both vegetative and flowering phases. Electron microscopy and x-ray analysis both confirm that existing silica within the plant is not mobile and cannot benefit new growth. To benefit new growth therefore, silica must be present at all times in the nutrient solution.

Various research projects have shown that the presence of silica in plant tissue produces several beneficial side effects:

● Silica produces healthier and stronger plant growth. When silica is taken up by the roots, it is deposited in the cell walls of the plant as a solid, rigid 'quartz-like' matrix. This produces a ‘mechanically’ stronger plant which enables superior leaf orientation and therefore greater rates of photosynthesis and growth.

● Increases the weight and shelf-life of fruit due to the physical accumulation of silica in plant cells.

● Increases plant tolerance to heat stress or “wilting”.

● Increases resistance to fungal diseases, particularly mildews and botrytis. It resists fungal ingress by accumulating around the points of fungal attack.

● Improves the healing rate and neatness of pruning wounds. This property is especially beneficial in commercial cropping of plants such as tomato and cucumber. Regular pruning of these species threatens the plant's survival due to the risk of disease penetration through the site of the pruning wound.

● Increases a plant’s tolerance to nuisance chemicals such as sodium and chloride.

Growers should note that many commercial silica solutions have a poor shelf-life. This is evident when the concentrated solution turns cloudy.