GARDENING | Seaweed biostimulants, the environmentally-friendly plant stimulants helping your garden grow

Helping your garden grow its resilience to the environment around it, more naturally. Picture: Shutterstock.
Helping your garden grow its resilience to the environment around it, more naturally. Picture: Shutterstock.

Maintaining plant health often involves the use of products like pesticides, fertilisers and soil ameliorants. Another range of products that have become popular with gardeners are biostimulants. So what are biostimulants?

Basically they are biologically-based products that can be applied to the soil or directly to plants for desirable plant growth. Biostimulants are neither pesticides, soil improvers or nutrients, but manufacturers often claim they will improve the efficacy of these products, and in some instances can replace them.

Biostimulants may contain nutrients but are not classified as fertilisers and promote plant growth by other means.

The diversity of biostimulant products is quite broad and play various roles to impact growth. They can enhance nutrient uptake efficiency, improve abiotic stress tolerance such as drought or frost tolerance and can increase plant traits, like fruit yield. They also have environmental benefits, like increasing beneficial bacteria in soils.

With an increase in extreme weather patterns due to climate change, biostimulants are becoming increasingly popular as a part of garden maintenance schedules to help plants cope under extreme conditions.

Every gardener knows that soil biology is the key to plant success - soil biology contributes to the fertility, productivity and sustainability of soils through organic matter turnover, improved soil structure, increased water holding capacity and a reduction in nutrient leaching and suppression of diseases.

Biostimulants containing beneficial microbes can assist in meeting these requirements when applied correctly.

One of the most popular biostimulants used in gardens across Australia is seaweed extracts due to their effects on plant growth and tolerance to stress factors, like salinity, temperature extremes, nutrient deficiency and drought.

Apart from the growth-promoting effects seaweed extracts have on plants, they also improve the physical, chemical, and biological properties of the soil. Even at low concentrations, seaweed extracts have been found to have a positive effect on plant growth.

It might be tempting to increase the concentration rate of any biostimulant applied in the garden to increase the benefits, but as with any product that influences plant growth, always follow the label directions.