This is an update on my previous report about vetiver/compost trenches. Our first attempt at making these trenches was a big success. Surprisingly so, because the compost in the trenches kept going down, down, down to where it looked like very little was left after 6 months. This was a little discouraging at the time because I used five pickup loads of manure and rice hulls, plus I was watering it fairly often. The surprising part was how much compost I got at the end of summer.
Our fruit trees get lots of compost and green manure. However, the open areas between trees don’t get pampered nearly as much. The compost trenches provided plenty of compost after all, enough for a heavy compost layer between trees. Another key advantage was 99% success rate at smothering weeds along the edges of the garden beds. This is where pernicious Bermuda grass in the paths sends runners toward the fertile garden beds and creates the most weeding work.
One mistake though was covering the manure with rice hulls instead of straw (straw wasn’t available at the time). The hulls gradually washed down into the manure and the exposed areas on the surface dried out quickly and required extra watering.
Here are my ideas for improving the process next time – compost trenches 2.0. First, hoe the trenches to removes grass and weeds that grow during the rainy season. Then cover the trench with a good layer of rice hulls. Then add manure, sugar cane compost or other fungal inoculated soil mix if available, and more rice hulls. Cover everything with a thick layer of straw and water thoroughly. The main idea is to use the same materials as when making compost. (Your materials may vary slightly, but you get the idea.) In our case, we know these low cost agricultural by-products produce good compost, so it makes sense to use the same process in the compost trenches.
Next time around using this improved 2.0 version there should be virtually no weeds or Bermuda grass runners, and much less watering. Plus, I’m expecting to get higher quality compost.
Note how our available area to make compost is limited, so utilizing compost trenches is beneficial for us. And, the compost in the trenches is exactly where we need it – right next to the garden beds.