The range of plant invigorators and water treatments on offer has increased significantly in recent years. Some look set to deliver growth effects in practice.

This has sparked interest in growth tests that highlight differences in plant growth in standard conditions. There are many different growth tests available, ranging from lab tests in Petri dishes to growth tests on a semi-practical scale. We have adapted one of these – the BioTest Phytotoxkit test – into a quick, relatively cheap and broad growth response test.

The test consists of a three-day germination test with three different crops, usually mustard, cress and sorghum. The test can detect minor differences with a high degree of certainty. Other benefits are the reports on both above- and below-ground growth, and the fact that effects due to differences in nutrients, pH and EC are excluded.

The test is too short in duration to test growth effects caused by microorganisms in the root environment, but it is suitable for determining growth inhibition caused by substrate and drain water. Separate growth tests are available for measuring the growth effects of microorganisms in the root environment.