Plant Positive Potting Soil
When I began my agricultural career at Stone Barns Center for Food and Agriculture, I was excited to see a two-yard sling bag of Vermont Compost Company Fort Vee outside of the farm’s propagation house. As a native Vermonter, I have a lot of pride in my home state, but at the time I knew little about the actual quality of the potting soil itself. A few years later, while spending a winter working for Eliot Coleman of Four Season Farm in Maine I noticed that he, too, was using Vermont Compost Company potting soil for his propagation. This was the first time I took the opportunity to think about why. What was it about this potting soil that made some of the most celebrated agricultural minds, and excellent compost producers in their own right, make this purchase?
Several years and a few farms later, I found myself back in Vermont, working for Vermont Compost Company. I’ve learned a tremendous amount from some excellent farmers since that first propagation season, and all of that experience helped me recognize the critical importance of potting soil. One management technique that I witnessed some of these farmers utilize was what Eliot refers to as a “plant positive” approach. This approach focuses on developing healthy, resilient plants and soils instead of treating the symptoms of sick and susceptible plants and soils. This commitment to the health of the plant was what helped me make the connection between the quality of the potting soil and the success of the farmer, and to understand why these farmers were investing in high quality potting soils.
The growers I worked for that utilized high quality potting soil like Fort Vee understood that their chosen land management practices took decades to refine, but the benefit of those practices were limited by the quality of the potting soil they were using. Seedlings are usually grown in +/- 1 ½ cubic inches of soil. That is a significant demand from a small volume of potting soil; so, how is one supposed to obtain healthy and resilient plants in this situation? There are a number of factors that come into play here, and many of them are related to management practices, but the best opportunity to develop these ideal plants is largely dependent on the capabilities of the potting soil.
From a small volume of soil, robust and resilient plants need a complete profile of nutrients and micronutrients, porosity for root development and water retention, adequate drainage and pH buffering capacity. Additionally, the potting soil those plants will utilize should be free of weed seed, provide microbial species richness (a fascinating topic with a growing volume of scientific information) and the opportunity for that species richness to turn into beneficial species abundance. The development of these characteristics begins with a mature compost derived from diverse ingredients that was intended for potting soil production. Their development is further enhanced through methodically selected and thoroughly researched inputs, and culminates in the careful incorporation of all components, safe and responsible handling practices, and constant performance assessment.
The growers that I worked for didn’t develop reputations for being excellent farmers by producing one great crop every once in a while. They developed their reputations by producing beautiful, healthy crops year in and year out and consistency is why they utilized Fort Vee. They found it to be a potting soil that performed admirably for them, and did so over many years. In potting soil production consistency is achieved by utilizing a mature, well managed compost, the highest quality inputs (carefully selected sphagnum peat moss, bone meal, coconut coir, etcetera), and care and attention to detail throughout the entire production process, not to mention rigorous quality assurance standards.
When selecting a potting soil, make sure you don’t underestimate the importance of the role it plays in your plants’ development process and how the success or failure of that development may impact your management practices and your farm’s bottom line. Once I began managing my own propagation space I chose a potting soil that I trusted and promoted the beginnings of a plant positive approach. Talk to other farmers you know are growing steady, healthy crops. Talk to your potting soil producer and ensure that they’re managing their compost well, utilizing good inputs, conducting bioassays to ascertain product quality, genuinely care about your farm’s prosperity and recognize how important a role potting soil can play in that success.
Kurt Ericksen is the Assistant General Manager at Vermont Compost Company in Montpelier, Vermont.