Brix and Plant Health

What constitutes a healthy plant? 
What makes a healthy-looking plant suddenly become enticing to insects? 
And why certain insects and not others?

One indicator of plant life is found in a measurement of the sugar content of the leaf.  You may have seen farmers checking the sugar content of fruit with a device they hold up to the sun.  This tool is a refractometer.  The sugar is measured in units known as degrees Brix.  This is a measure of the dissolved solids in a liquid.  Different concentrations of dissolved solids refract light differently and the refractometer measures this.  The higher the degrees Brix, the more dissolved solids in the liquid.  As many scientific methods are, this one too was named after the scientist who discovered it, Adolph Brix. The value is grams of soluble solids per 100 grams of solution.

Brix levels can fluctuate with the weather.  Plants can anticipate storms and move sugars into the roots to store as it may be needed for damage from the storm.  Dehydrated plants will show a higher Brix level because the dissolved solids become more concentrated. What I found interesting is that ranges of leaf Brix correspond to certain insect groups.

The way to improve the plant health is to improve the soil.  Fertilizing alone won’t do it.  As our bodies cannot use the food we eat without proper gut health, so it is with the soil.  There is a lot that healthy soil can accomplish and it can be as simple as regularly adding composted organic matter into the soil.

Photo from “Understanding Brix and how it affects plants and pests”, December 22, 2022, The Joe Gardener show.

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