Activity – Grow test
Instructions and Observation When soils are amended with compost containing persistent herbicides, you’re likely to see stunted growth and reduced fruit crops, failure of secondary leaf sets and/or compound leaves staying single. The most vulnerable plant families where these impacts will be evident are legumes, nightshades, cucurbits and composites. Therefore, performing a grow test using seeds from one of these plant families can provide compost users with important information. To perform a grow test, sow a small amount of bean or other (nightshade, cucurbit, or composite) seed in the compost you want to test. The first leaves to emerge upon germination are the cotyledons, and true leaves emerge shortly after. The true leaves will reveal either healthy or compromised leaf growth. Tomato plant affected by aminopyralid herbicide residue from contaminated manure, grown July 2008, Cheshire, UK. Note tightly curled leaves, which is a symptom of aminopyralid contamination.
49
