We have learned that quality produce on our eight-acre vegetable farm starts with the soil—soil that teems with life at both the macro- and micro-level.
First, some background: I had grown up on a conventional hay, corn and soybean farm in western Iowa and moved to Rochester, Minn., for work after getting a mechanical engineering degree from Iowa State University. I like engineering, but after a few years of working in an office environment, I was feeling the urge to get dirt under my fingernails and have a better way to spend time with my young children.
My wife Lisa and I eventually took LSP’s Farm Beginnings course and bought an eight-acre farm in southeastern Minnesota 12 years ago. But before we bought the farm, we got started in food production by expanding our personal “farm beginnings” to encompass a quarter-acre garden, and we began marketing at the Rochester Farmer’s Market.
The soil on our quarter-acre “micro farm” started as red clay. The developer had sold off all of the topsoil when he built our home, leaving only C-horizon clay subsoil, which is a great subsoil with a high cation exchange potential. The key word here is potential—red clay without a generous cover of organic matter is a slippery mess in the spring and hard as a brick in the summer.
I started to rebuild this soil. I first double-dug the beds and added compost to both the upper and lower layers. I had taken some extensive classes from John Jeavons, author of How to Grow More Vegetables, a few years before. John teaches the biointensive double-digging technique for farms up to a quarter-acre, and his growing approach encourages some of the best high-density planting approaches (while at the same time building soil) that I have found. Many of these techniques work well in depleted soils or in Third World situations, which was just what I had to deal with.
We worked on rebuilding this soil for seven years before moving to our new eight-acre farm, and when we were done it was some of the best soil I have ever seen. We added compost and more compost. The compost clay blend was wonderful. The spring muck and summer brick-like consistency had morphed into a beautiful topsoil that was 36 inches deep. I had originally double-dug 18-24 inches deep, and the soil life had expanded the horizon both up and down. We never walked on the soil after that initial double- dig to minimize any type of compaction.
I could literally press a 3/8 inch metal rod into the soil 36 inches with my bare thumb, the soil had that deep a structure. Water and air penetration was excellent and I never had any erosion. Earth worms were abundant. I always had a cover crop on the soil, mostly vegetable-related, and I would often get up to four crops per year from a given space, and always at least two if I count soil- building crops. It isn’t difficult, but I’d never heard of anyone doing this, especially this far north in Minnesota.
This growing strategy would be difficult to replicate on 20 acres, for example, as it involves very intensive hand work. The point of explaining all this is to learn the principles and what vegetables “look like” when grown this way. If you know what the gold standard is, you will be motivated to achieve this level of quality and won’t stop until you get there, no matter what method you use. This is important background information because I believe what we do with our soil comes from the vision and values of the farmer, as much as the training and knowledge he possesses.
Building the Soil on a Larger Scale
Now back to our new farm.
When we moved to our farm after graduating from Farm Beginnings, the land had been farmed conventionally with corn and soybeans. Nothing unusual about that—the farm had not been abused, it wasn’t overgrown to weeds or highly eroded. I’m sure the former owners had been using the typical agricultural chemicals, fertilizers, corn and bean varieties. We had good soil types to work with. The soil types were, in fact, far better than at our previous home where the topsoil had been sold and all that was left was red clay.
However, the soil on our new farm was “biologically DEAD.” Maybe It would be more correct to say the soil was biologically suppressed—the biology was there but it was dormant and had to be awakened. I couldn’t double-dig eight acres, nor did I just want to scale up a boutique growing technique. I wanted to learn how to do this on a larger scale but with the same quality goals in mind.
Remember that soil we rebuilt from the red clay at our previous home? That soil was 800 percent more productive than the soil of our new farm. It took two acres on our new farm to grow organically what we had been able to do with a quarter-acre at our old garden. The flavor, shelf life and visual appeal wasn’t nearly as good either. That first year I also noticed deficiencies of minerals such as calcium.
So we got to work:
- We spread lime on the whole farm for two consecutive years to replace calcium “mined” from the soil. I also added kelp meal and rock powders the first few years to replenish the minerals that are so important to the flavor components of the vegetables.
- We grew green manure cover crops—sometimes several a year—to feed the soil micro-organisms and wake them up. Our goal is to always have either a vegetable crop or a cover crop on the soil at all times.
- We composted, composted and composted some more. I don’t buy much organic fertilizer. I put most of our fertility investment into compost. For the cost of a bag of organic 8-4-5 fertilizer, I can buy a whole ton of compost and grow 10 tons. I vote for compost! Through the compost, we added humus, biological life and minerals to refill the soils dwindling “fuel tank.” Between the cover crops and composting we have added four million pounds of compost to our eight tillable acres in 12 years. This is an investment of over $50,000, but is priceless in terms of soil development.
- We are now experimenting with more advanced techniques like sequestering carbon with biochar, multi-species cover crops, double-cropping, and letting our choice of cover plants do the double-digging for us.
You can’t believe the difference. A neighbor was flail chopping one of my cover crops that would then be made into compost. He said he had never seen such a massive amount of organic matter. The cover crop was hairy vetch and winter rye. I think we got about 20 tons from 1.5 acres. I was preparing the soil for a crop behind his chopper and the soil was amazing. This was three years after we started to farm here. It has only improved from there.
It took four to five years to get to an acceptable level of quality and at the 12-year mark our customers tell us it is still quite high. But I still have that vision for excellence that we are striving for. Is that just the Holy Grail that you look for but never find? No, I don’t think so. The more we study the secrets of the prairie and forest soils, the more we understand the path to excellence. It is all there: we just have to look and listen. Sometimes we have to think small to understand these processes and then figure out a way to incorporate them into our farming approach.
When the soil is right, the vegetables are right. When the soil is healthy, the vegetables are healthy.
So our quality story begins with the soil. Yes, you pick good vegetable varieties and grow them well. Yes, you harvest at the right time. Yes, they are clean and fresh. Yes, they have good flavor. Yes, they have excellent shelf life.
But the foundation for food quality is the soil!
Brian and Lisa Petersen are 2001 graduates of LSP’s Farm Beginnings course. They, along with their children Andrea, Jenna and Reed, raise vegetables north of Rochester, Minn. Brian blogs at VegetableFreak.com.