Lamoille Soil Compost is marketed as being “Compost to Grow With,” and we wanted to put this to the test by conducting bioassays with our compost and topsoil. A bioassay is defined by the free dictionary online as a method of determining the concentration, activity, or effect of a change to a substance by testing its effect on a living organism and comparing this with the activity of an agreed standard. The purpose of conducting our bioassays at Lamoille Soil was to test the effect compost had on bean and lettuce plants, in comparison to topsoil.

The bean and lettuce plants were started from seed, and planted in different mixes of topsoil and compost. The planting mixes were: 50% compost, 100% compost, 25% compost, and 75% compost. Measurements of germination, number of leaves, and length of the plants were taken twice weekly in order to compare growth of the plants and the growth of the plants were tracked over 4 weeks.

            After four weeks of the plants growing, trends in the data were becoming evident. The plants grown in 25% compost and 75% topsoil displayed the highest number of leaves and longest stems (averaged between 6 plants). At Lamoille Soil, we recommend that our compost be applied to seedlings in a mix of 1/3 topsoil, 1/3 vermiculite and 1/3 compost. The findings of this bioassay prove our suggested ratios to be effective, as the mix containing 25% compost grew slightly larger leaves at a faster rate than the standard topsoil.    No plants were showing any sign of damage on their leaves or stunted growth, which was a great indicator that our compost is persistent herbicide free! The plants were then given out to our staff to finish growing in their summer gardens.