I finally found some time to look at the soil test reports and to compare them to each other and to last year (less to do in the garden means more time to spend doing other things).  The results were neither earth-shaking nor even startling but there were some changes, all of them for the better.

First—and most important—the soil pH for the east planter fell to 6.31, well within the optimal range (as recommended by Rutgers) of 6.20 to 6.80.  Last year, the pH was at 7.38, or slightly alkaline, and too high for most vegetable plants.  We added elemental Sulfur in the spring (see February 20, 2012) and it appears to have done the trick.

Similarly, the soil pH for the west planter was in the acceptable range—just barely—at 6.78.  The main difference between the soil in this planter versus the soil in the east is a lower proportion of compost.  Therefore, it would appear that the compost has a higher pH than the soil or peat moss.  By using less of it, we started with a lower pH than we did with the east planter last year.  For both planters, we will not need to make any adjustments (no Sulfur, no limestone) next spring.

Of lesser importance (and, perhaps, interest), the concentrations of macronutrients—Phosphorus, Potassium, Magnesium and Calcium—in the east planter have decreased, although all but one remains above optimum.  The exception is Potassium, whose concentration has dropped into the optimal range (whatever it is; the optimal ranges are not noted in the report).  The reduced Potassium concentration and the still-high Calcium concentration are consistent with the drop in pH and the recommendation not to add limestone (which is mainly Calcium Carbonate).

The macronutrient concentrations in the west planter are very close to those in the east with the exception again being Potassium.  Its concentration is higher and very near to what it was in the east planter last year.  That might explain why the west planter’s pH is higher.  The interactions between macronutrient concentrations and pH are very apparent from the testing results.

Finally, the concentrations of micronutrients—Zinc, Copper, Manganese, Boron and Iron—in both planters remain more or less the same.  They are for the most part classified as adequate (with no explanation of what that means) with Manganese and Iron falling into the high category.  These concentrations do not seem to have much impact and all are deemed not a limiting factor by the lab techs.

The bottom line is that as long as we maintain pH in the optimal range and continue to use balanced fertilizers, our soil will be just fine.

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