Broadening Organic: Nutrient Dense Foods

Written January 4, 2013, published in mid January 2013. All photos by Kathleen Sayce.

The debate about organic versus convention food production goes back and forth. One study says organically grown food is healthier. Another says there is no difference in nutritional value between organically- and conventionally-grown foods, except for the level of pesticides. No surprise, organic foods have lower pesticide levels. A third says that soil amendment costs are higher on conventional farms, lower on organic farms. Another says labor costs are higher on organic farms due to more hand weeding. Organic food gardens cost less to operate, because fewer amendments (fertilizers, pesticides) are used, and less water is needed. Conventional food gardens produce more food for lower labor costs, but at higher health risks for farm workers due to pesticide use. 

A refractometer with three kale samples, from left to right, Red Russian, Red Curly and Green Curly Kales. 

Food Quality

What’s a home gardener to conclude from this argument? I say:  Expand your definition of organic gardening and look at food quality, specifically at nutrient density:  What form of gardening produces the most nutrient dense food?  ‘Properly mineralized soil’ is the correct answer. This goes beyond avoiding crunchy, sugary, salty processed foods, as good as these taste, to plant and animal foods with high quantities of minerals, proteins, fats, sugars and secondary compounds. This is nutrient density, which we can measure, and more importantly, we can taste.  

Plants grown on optimally healthy soils have higher levels of dissolved solids and minerals in their intercellular sap than do those grown conventionally or on nutritionally out-of-balance soils, regardless of the management method for that soil. These plants are healthier, and their roots, fruits and leaves and stems, which we eat as foods, are more nutrient dense.  They deliver optimal food quality and flavor to us, the eaters.  Likewise, animals grazed on pastures managed for optimal nutritional health are healthier. 

A light orange carrot with mashed fresh carrot in cheesecloth, ready to measure the carrot's juice in the refractometer.

Nutrient Density

Density is measured as dissolved solids in plant juices using a refractometer, a centuries-old device that uses refraction of light to measure fluid concentrations in Brix units. A bar of color crosses a numerical scale; you read the number on the scale. This is the Brix of that solution.  In measures of plant sap quality, the higher the Brix, the better. 

Wine, cheese and juice makers use refractometers to measure Brix and determine ripeness in grapes, tomatoes, berries, and other fruits, because there is a strong correlation between the level of dissolved solids in intercellular sap, and the sugar levels and flavor of the fruit. They often eat the fruits to compare flavor to Brix units, calibrating their sense of taste to these measurements.  Yes, you can taste the differences. High Brix fruits have more flavor. I use my garlic press to mush fresh veggies, and a bit of cheesecloth to squeeze the juice from the crushed sample to test. 

Studies of food quality rarely include the Brix levels of plant saps. Those few studies that do so show that fruits, grains, seeds, and vegetables grown on healthy soils with optimal nutrient balances have higher Brix levels than do conventionally grown foods on unbalanced soils.  

A green curly kale sample in cheesecloth with bright green fresh juice.

Food Quality, Flavor and Health

As consumers of mass-produced foods, many of us have never tasted these flavor differences, due to lack of exposure to truly nutrient dense food. Bring on the compost, humus and biochar, and soil tests for minerals, so that we can determine exactly which minerals our vegetable gardens need. In a healthy soil with optimal levels of nutrients, all of those plants, including fruit vines and shrubs, peas, carrots, beans and even lettuces, will nosh in style, and deliver more nutrition and flavor.  

The result of eating plants grown with optimal soil nutrition is that we can be healthier. So step aside of the arguments about conventional versus organic, and go beyond, into an expanded definition of organic gardening with nutritionally complete soils, with regular soil tests, appropriate mineral supplements, and grow healthier plants. Get optimal flavor, high mineral levels, and higher levels of sugars, proteins, fats and other flavorful compounds. 

Anyone can do this. Gardening is not difficult; it takes time, and soil tests to determine what amendments your soil needs to optimize nutrition for your home garden, orchards, lawn or pasture. The gain is in taste and health.  Steve Solomon’s latest book, The Intelligent Gardener, discusses soil nutrition for growing optimally healthy foods in sufficient detail to get you started. 

Winter is a great time to be planning next year’s vegetable garden. Order soil tests, then add the right minerals to improve your soil, for great eating next summer. Summer is coming, right? The rain will end sometime, right? 

A red curly kale sample with its red-purple colored fresh juice. The chlorophyll is in there, but masked by the reds and purples of the red kale plant. 

Healthy Soils for Healthy Vegetables

Written December 12, 2012, published in late December, 2012, all photographs by Kathleen Sayce

Soil health for vegetable gardens is more precise than for ornamental gardens and native plants. Most vegetables are annuals or biennials, living only one year, or over one winter.  All of are from other places and climates, with nutrient and soil needs considerably different than local soils can provide. Vegetable plants need:  Deep, open, well-aerated soils with soil carbon, diverse minerals, sunlight, warmth and regular water. With these, they grow quickly into tender, nutritious and edible foods; without them, vegetable plants struggle, easily fall ill, and fail to thrive. Vegetables generally are not shade plants, especially along the raincoast; warmth and regular watering are needed for vegetables to grow well. 

Well-grown vegetables are able to resist weather, diseases, insect pests, and have high levels of minerals, proteins and other plant compounds. This photo of Red Russian Kale was taken in Jim Karnofski’s vegetable garden by Kathleen Sayce.

Soil Carbon

As with other kinds of plants, vegetable plants need soil carbon. The forms that are the most usable for vegetable plants are not aged wood chips or forest debris, but well prepared compost with humus, and biochar (biologically activated charcoal). Vegetable plants use soil carbon throughout their root growing areas, so gardening practices for optimal plant nutrition incorporate carbon of several kinds throughout the soil profile. Gardeners work carbon into the soil with a rototiller or shovel, add layers to the surface, side dress plants, and amend planting holes. They also fallow garden sections every few years, planting cover crops to put more carbon back into the soil. 

Carbon promotes soil health by giving soil organisms food to eat (carbon) and places to live (cellulose scaffolding). The one drawback is that, being formed of cellulose (wood), most forms of compost break down quickly. So gardeners need to add compost regularly, year after year. Only humus, a brown, clean-smelling, somewhat sticky substance, persists for decades to centuries in soil. Compost piles can form humus if clay and local soil are added to each layer. 

Compost with charcoal added is dark colored, and is now ready to go into the vegetable garden.  Photo of one of Jim Karnofski’s compost bins.  

A second soil carbon material, biochar, is charcoal that has been activated with compost or soil microbes. Biochar has an advantage as a soil amendment: charcoal is stable in soils for centuries to millennia. When gardeners add biochar, this is a permanent improvement in the soil. Add biochar along with compost, and over time, you will have the same productivity with less compost. 

Making Biochar

When wood is burned, charcoal is formed during the burning process. If burning is complete, the wood goes to charcoal and then to ash. Starving the fire of oxygen (a process called pyrolysis) promotes charcoal formation and keeps the fire from consuming all the wood. Innovative pyrolysis burners are being developed at backyard and industrial scales to produce large amounts of charcoal with minimal amounts of ash. When the charcoal is wet and cold, it can be added to compost to be inoculated. See  HYPERLINK "http://www.biochar-international.org/" http://www.biochar-international.org/ for biochar producing devices. A short video for an introduction to home charcoal making is on You Tube at  HYPERLINK "http://www.youtube.com/watch?v=dqkWYM7rYpU" http://www.youtube.com/watch?v=dqkWYM7rYpU .

Freshly made charcoal is ready to go into the compost pile when it is wet and cold, and broken into small pieces. 

Mineral Nutrition

The second soil management practice for optimally healthy soils is to use soil tests to determine what minerals are needed, and then to add those missing minerals in the correct amounts. Soil tests are inexpensive, and a simple way to ensure a garden is not over-fertilized with some minerals and too low in others. It’s a good gardening practice to test soils in your vegetable garden and adjust your fertilizer program every year. Minerals can be added as rock dusts, algae extracts, and other forms.  The differences in terms of productivity can be staggering; I’m not talking ten percent increases or even twenty. At times, improvements can be on the order of multiples, as measured by plant weights or volumes, fifty pounds of potatoes instead of twenty, for example.  

Jim Karnofski, local vegetable gardener and retired nurse, has delved into soil mineral nutrition as a neighborhood soil analyst, and is wiling to teach anyone interested in learning the details how to decipher soil test results. He also makes custom nutrient blends for specific soils. I tested my soils a few weeks ago, after years of adding carbon, trace minerals, and organic fertilizer blends. I found that my soils are surprisingly low in boron, manganese, sodium, copper and sulfur. Jim composed a custom blend to meet the nutritional deficiencies based on the soil test. I’ll add a portion of these missing nutrients every few months, test again in coming years, and keep adjusting minerals to improve my soil. A new book by Steve Solomon, The Intelligent Gardener: Growing Nutrient-dense Food, goes into splendid detail about vegetable nutrition. 

The sum of all of these actions (adding carbon, testing soils and adding mineral nutrients) is to have optimally healthy soils. Healthy soils produce healthy plants, able to resist disease, drought and insect predation. In turn, healthy plants produce nutrient-dense vegetables and fruits, which are better foods for us.  Many chronic human health conditions go away when people make the change to eating fruits and vegetables grown on optimally healthy soils. I think we’d all like to live healthier lives, and my personal task for the New Year is to promote soil health, so as to promote human health.