Rabenberg on brix

The Walden Effect: Farming, simple living, permaculture, and invention.

Rabenberg on brix

"Brix" is one of those terms tossed around by folks in alternative agriculture circles that I considered a little kooky in the past. The idea is simple --- you use a meter to determine the percent by weight sugar in a plant, which gives you a rough estimate of the nutritional quality of the food since more nutritious crops are usually also sweeter.

Even though I agree with the theory behind brix, I used to roll my eyes at the implementation. I can taste the difference in brix between my homegrown vegetables and the ones in the grocery store, so why buy a $100 meter?

Glen Rabenberg's talk on "Improving crop quality using readily available tools" helped me realize that my understanding of brix in the garden is overly simplistic. He doesn't just check the brix of crops being harvested; he monitors plants at various stages of their life span to prevent disease and insect problems.

Rabenberg asserts that at increasing levels of brix, farms become healthier in a holistic fashion. Disease fungi and thrive at a brix below 7, but when the leaves of a plant reach a brix of around 10 to 11, Rabenberg sees drought resistance in the crops and fewer weeds nearby. At 13 to 14, he begins to see resistance to pest insects. Having recently seen in a scientific source that the fire blight bacteria are deterred by high levels of sugar in pear nectar, I'm willing to believe that there's some truth to Rabenberg's ideas.

So, how do you raise the brix of your food? As with plant secondary metabolites, the key is balanced soil. Rabenberg believes that most soil problems can be remedied by focusing on five minerals --- calcium, phosphorus, and (to a lesser extent) potassium, magnesium, and sulfur. If Rabenberg sees low brix, he performs a soil test and usually adds calcium and/or phosphorus on the theory that a more nourished plant will produce more sugar and be more resistant to problems. In his experience, potassium is actually often too high, leading to weed problems --- if that's the case, you need to round out your fertilizing campaign to prevent a buildup of the important, but easy to overdo, nutrient.

I know I've said "asserts" and "believes" a lot of times in this post --- it's not because I don't think Rabenberg is on the right track. However, I want to read up more on the topic before I take his word as gospel, and suggest you do too. Still, perhaps Rabenberg is right and I need to start collecting data on the brix levels of our crops (and on the electrical conductivity of our soil, a topic which will have to be its own post at a later date). Perhaps if I noticed when tomato plants were most at risk, I could head blights off at the pass?

Find out how to test your soil and interpret the results in Weekend Homesteader.