Tuesday, September 16, 2014

VegHeadz Garden News - Sweet Potato Harvest, Cover Crops, Changing Soil pH

We were busy at the garden this morning.   Thanks to Sue, Cathi A., Laurie, Marie, and Janis we harvested sweet potatoes and yams, amended the C and D rows in an effort to lower the pH and sowed Abruzzi rye in one of the C rows as a cover crop.   Rye will also be sown in the other two C rows which will be planted with potatoes and peas early next year. 

Late in the spring we had planted a variety of sweet potatoes and yams in our perennial garden.  The Japanese Yams (red on the outside, creamy flesh) were the most prolific.  Eight or ten very large tubers were crowded together under the vine nexus where the original slip was planted.   They can be found not far under the surface, and they extend vertically down quite deep so they have to be carefully dug out.  They bottom part of the potato can be as much as a foot under the surface of the soil.  They are excellent at opening up your soil for future crops.  By the time you have dug the potatoes, the area is thoroughly aerated.  We left tiny potatoes and portions of fleshy roots in the soil to produce next year's crop.
Sue and Cathi with our sweet
potatoes and yams and a couple of
butternut squash
The soil pH in our garden tested somewhat high on our last soil test (7.1) while most plants fare better in the 6.5 range.  When looking at a chart of pH requirements for individual vegetables, you can almost detect your pH level without a test by noting which plants are thriving and which are not.   The pH is probably at the level preferred by the thriving plants.   If the pH was too low (too acidic), it would be relatively easy to raise it by adding dolomite lime.  Lowering the pH to make soil more acidic is more problematic.   The addition of elemental sulphur along with peat moss is one way of handling this. 

We took another soil test in just half the garden (C and D rows) and we are amending the soil as follows:  For a 25 foot row about three feet wide (approx. 75 square feete), we are mixing 1 part garden soil from the row, 1 part mushroom compost, and 1 part peat moss.  We combine them in a wheelbarrow along with 1 cup of sulphur.   Mix well and spread on the row.  It purportedly takes several months for the pH to change, and the change should not be dramatic.  We hope to bring it down under 7.0 at least.   We'll take another soil test in the spring to see how we did, and we'll watch our plants closely to see how they react.   If it works, we'll apply our remedy to the other half of the garden in the spring. 

Cathi and Sue at the end of the C row that has been sown with
Abruzzi rye after amending
with peat moss, sulphur, and mushroom compost
We are also planting Abruzzi rye as a cover crop in the rows where peas and potatoes will be planted (C rows) in January and February.  Trevor pointed out nematode nodules on the roots of the plants in those rows this summer and rye grass is reported to discourage nematodes. 

As soon as the weather gets just a little cooler, we'll be sowing and planting our winter crops.  They should look pretty good by our Fall Open House on November 1.   Hope you will plan to be there.\


  1. I wonder how effective time are going to be in lowering the soil pH? http://www.ncagr.gov/agronomi/pdffiles/pinebark.pdf
    Graco in Cairo Georgia sells it for $18 a cu yd