Using biostimulants in horticulture

AHDB has partnered with organisations across Europe to help you use biostimulants effectively.    

The Bio4Safe database presents scientific data on plant biostimulants for growers. You can search generally on any search term or you can filter by desired effect, biostimulant type or crop. After searching, you get an overview of biostimulants.

By clicking on a biostimulant, you open the data sheet with the following information:

• The biostimulant (type, company)
• Description of the effects and trial details (greenhouse/field trial, stress conditions and country)

Tested crops and application (method, timing and rate) and source 

AHDB has reviewed information on the use of biostimulants to optimise flavour in herbs.

Research applications of foliar sprays of salicylic acid at rates of 0.5mM for 15 days before harvest (with 0.5mM applied every three days; there were five spray applications in total) increased oil content by up to 30%, but it did not affect composition. This is thought to be the result of increased potassium and iron uptake from soil as a stress response to perceived infection risk.

Jasmonic acid has been found to increase quality and quantity of essential oil in basil, while methyl jasmonate can lead to high production of linalool and β-ocimene, so increasing quality. Application of these growth hormones might represent a way to alter the essential oil profile of basil.

Studies and research

One study has shown that biostimulants could alter the essential oil composition, with aminoforte (an amino acid mixture) and nitroxin products resulting in the highest total essential oil yield. Their ideal treatment was kadostim×nitroxin and fosnutren×nitroxin as this gave the best oil composition.

Although research is limited in this field, artificially inducing a stress response by treatment with salicylic acid or other growth regulators seems to have the potential to improve basil essential oil content and quality. The response of a plant is cultivar-specific, and the treatments may affect other important factors such as physiology and yield.

Mycorrhizae may aid growth in general, especially in substandard soils. However, there has been no reported effect on flavour, with studies showing no difference when treated with mycorrhizae.

In studies using cell cultures, the use of salicylic acid increased the production of ACSO significantly, although it is not known if there is any effect on commercially produced plants.

Salicylic acid and ascorbate have been shown to increase the total oil content in trials carried out in Egypt. Spraying the plants with either acid or ascorbate increased their oil content, but applying both together produced a larger effect than either alone. It is not known how this impacts the composition of the oil or the overall flavour.