Introduction

Revive Eco develop green technologies to produce high value products from waste. Their initial focus is on waste coffee grounds from which they extract several high value chemicals and consumer products.

Challenge

Following Revive Eco’s extraction process, the company are left with extracted coffee grounds (ECGs) as a residual material. It is important to Revive Eco to ensure they produce as little waste as possible. This project investigated whether ECGs could be used in agriculture to bulk out compost used to grow lettuce and strawberries. If successful, ECGs would have the potential to replace peat or coir based soil additives, providing additional environmental benefits.

Solution

Revive Eco supplied ECGs to JHI, who used their expertise in the horticultural sector to test the ECGs as an additive to compost to see whether agriculture would be a suitable end point for the ECGs.

Various concentrations of ECGs were added to compost in which strawberries and lettuce were then grown. Measurements such as the number of strawberries a plant produced, height of plants, number of leaves etc were taken and the experiment repeated at different concentrations to determine what incorporation levels were optimal.

Outcome

There was a small improvement in fruit yield when a small amount of ECGs was incorporated into the growth substrate. There was also an increase in propagation, which was an interesting result that could be worth exploring further. Lettuce growth, however was severely reduced with ECG addition.

There may still be a place for ECGs in strawberry growth substrates to replace peat and coir, but the results of this project mean this avenue can be deprioritised in favour of other potential uses, such as biochar or exfoliation.