No Till Garden Experiment

23 Aug

This spring I tried a no-till system for the second time. Twenty five years earlier I covered a portion of our rainy Hillsboro, Oregon garden with black plastic, hoping it would be drier in the spring and allow an earlier planting. The plastic was in place about 5 months. It was partially successful – the soil was easy to fork, as there were no live plants in it. It was very wet. It had a musty smell to it I didn’t like.

In 2017 I revisited a tarped no-till method. This trial was in Arroyo Grande, California, where we got 30” of rain in the winter of 2016-2017. The tarp I used was stiff enough for airspaces beneath it, unlike the black plastic. The tarp wasn’t in place for very long; about 6 weeks was all it took to kill the weeds. I used the worst part of the garden for this experiment, an area which never amounted to much. I had done comparative soil tests and know the mineral profile of this section is as good as the more productive parts of the garden. I took the failures to be because of intense root competition from neighboring trees.

When I pulled back the tarp I was amazed to see a proliferation of earthworms. They are otherwise very rare in my garden. I scattered quite a bit of feathermeal on the surface, along with the slightest bit of borax possible, and a sprinkling of gypsum for sulfur. These anions leach easily, and often have to be replaced for every crop. The other minerals, the cations, were already in place after years of soil testing and mineralizing.

I had some extra cabbage plants, so I began transplanting them with a trowel; with just the minimum digging necessary to get the plants into the ground. The soil smelled good. As I had a bit of purchased Black Diamond vermicompost around, I dug one or two handfuls under the transplants in the top row before transplanting. I was fortunate to get the Black Diamond vermicompost; all vermicompost is not the same. Black Diamond has been chosen for the vermicompost trials at Ohio State (and small quantities are available by mail). This is a very tough test of the vermicompost; the bottom row of every bed does better than the top row.

I labeled the rows, and pretty much left them on their own until harvest. The rows got drip irrigation added about 40 days after transplanting (the ground remained quite wet after transplanting). They got weeded and mulched. Maybe kelp was foliar fed a couple times. That spring we were traveling a lot, and the garden didn’t get much care.

When I went to harvest a cabbage, the most mature and best looking one came out of the top row, the row with vermicompost. We took it to the 3 day Live Oak Music Festival where the temperatures were in the 90s. The cabbage was still very good on the third day, without any refrigeration. Quite a surprise. The top row matured earlier than the bottom row. The top (vermicompost) row yielded more.




For comparison purposes I paired cabbages from the top and bottom rows which were right below each other. In my garden not only does the bottom row grow better plants, but the plants to the left yield more than the plants to the right.
Here are photos of the paired cabbages. The cabbages with the vermicompost are on the right.
All the cabbages are a bit over-mature, though they still taste good.

Erica Reinheimer
Soil Analyst, Grow Abundant Gardens
July, 2017