Wide Row Planting and Trench Composting in the Vegetable Garden
(Listen to my podcast on composting "Black Gold")
Composting is that magical process in which garden waste, water weeds, kitchen scraps, dryer lint and other organic materials are turned into a dark, nutrient-rich soil amendment that looks nothing like the original materials. Microbes, those unseen soil inhabitants including bacteria and fungi, do most of the work, but worms and other larger critters play important roles as well.
I wrote an article Composting for Your Garden in 2006, which continues to be one of my most visited articles. I also included even more details about various ways to compost in Chapter 3 of my book. Since 2004, when we moved to northern Florida, we've produced many huge piles of wonderful, rich compost. Our successful vegetable crops over the years make the case for using compost alone to fertilize crop plants.
In previous articles I've mentioned in broad terms that trench composting can work in vegetable gardens, but now let's fill in some details, so to speak. The wide row planting arrangement that I use in most of my vegetable beds is perfect for trench composting.
Wide row planting: the details
Wide row planting is one of the intensive growing arrangements used to cram as much growing area in small spaces as possible. Square-foot gardening is another popular intensive arrangements where you lay down a one-foot grid over your garden and plant crops at just the right distance from each other within each foot. Wide row planting is less rigid: rows can be 6 to 20-inches wide with the plants spaced so they are just the right distance apart. In between the rows is a 6-inch deep trench that is 4 to 20-inches wide depending upon how much room the crop growing in the adjacent rows will need. The rows are short (No more than five feet long), so you can reach into the growing area without stepping on the soil.
This wide row planting has a 20-inch-wide row on the left with sweet onions spaced four inches apart and a 10-inch-wide row with broccoli plants alternating down the row. In between, the six-inch wide trench is filled with pine needles. When the broccoli plants fill in you won't be able to see the trench from this vantage point.
The trenches between the rows allow for water drainage during heavy rainstorms and provide enough space between the crops. Trenches should be heavily mulched with easy-to-remove materials such as pine needles, straw or dead leaves. Mulches such as sawdust or wood chips don't work well for mulches where there is so much activity, because they would be too hard to rake away. I fill my trenches with pine needles as mulch right up to the level of the planting surface to keep the weeds down. There are lots of pine needles in our neighborhood, so this is a free mulch for me.
Trench Composting: What, when and where?
The term is descriptive of the process: you compost in a trench. It is most often used by small vegetable gardeners within their planting spaces, but well before any crop roots have reached the area, because you don't want to damage the roots. So trench composting is only useful when the crops are still small or as you're planting the crops. First remove the mulch, dig the trench another 4 or 5 inches deeper, lay in a 3-inch layer of kitchen scraps (no meat, bones, oils, or fresh manure), cover it with one or two inches of soil, and then replace the mulch. You are not limited to kitchen scraps, you could also use the remnants of your crops (as long as they are not diseased), grass clippings or other green compost materials.
Recently I transitioned between our cool-weather and warm-weather crops: from lettuces and bunching onions to okra and peppers in one area of the garden. The onions and the lettuces had been arranged into three rows with narrow trenches. After I'd harvested the last of the onions and pulled up the stubs of the lettuce plants, I raked away the pine needle mulch (for reuse) and then dug in some finished compost (from my big compost pile) to enrich the soil before planting the next crops. I then rearranged the area into two rows (instead of three), because the new crops will take more room. The trench between the rows is wider, too.
I dug deeper between my new rows, laid in my kitchen scraps and covered them with soil, gently tamped it down, and covered it all with pine needles. By the time these new crops have roots long enough to reach the kitchen waste deposit, it will be dark, rich compost filled with with macronutrients, nitrogen (N), potassium (K), and Phosphorus (P) and many micronutrients, particularly calcium, because of the eggshells.
In this photo, the trowel is lying over the trench, which is mulched with pine needles, in the area where I'd buried the scraps shown in the lead photo. This trench between the rows is about 10 inches wide. I planted two okra seeds in each of the five holes in the wide row to the right of this photo. The spacing between plants is supposed to be 12 inches. Note on the circles between where I planted the seeds: they are shallow basins to make it easy to hand water the okra so the water stays put and doesn't roll off the hill. Then I planted several nasturtiums below the okra and next to the walkway. Nasturtiums are in my edible garden for two reasons: 1) they'll attract pollinators and 2) they're edible and their slightly peppery flowers and leaves will grace many of our summer salads. And oh yes, they are beautiful!
I planted three bell pepper plants in other row, to the left of the trowel. They have cardboard collars around them to keep the cutworms at bay and soon I'll place three tomato cages over them to keep them upright. There is no trench between the pepper row and the parsley row. By the time the peppers get serious about growing in the summer heat, the parsley will be gone. I'll just mulch over the parsley row after their final harvest. I will not dig a new trench at that time because the pepper roots will be in the area and I'll also just cut off the parsley rather than pull it out so I don't disturb the peppers. So now this part of my garden is arranged for the summer and will be rearranged yet again in late fall to make way for the new winter crops, but not lettuce and onions. I'll plant sugar snap peas and carrots to complete my crop rotation.
Composting: a gardener's best tool
If you haven't done any composting yet, read Composting for Your Garden, and you should be ready to try some trench composting, too. You'll reap more and better-looking crops. I know you'll love eating from your garden the way we do. Both you and your wallet will be in better shape.
Ginny Stibolt moved to northeastern Florida in 2004 and even though she's a botanist and lifelong gardener, Florida gardening was a shock. She started writing The Adventures of a Transplanted Gardener columns for the Times Union newspaper in Jacksonville. This is one of those columns archived here on Floridata.com for your enjoyment. Now she's written three Florida garden books published by University Press of Florida: Sustainable Gardening for Florida, 2009; Organic Methods for Vegetable Gardening in Florida with Melissa Contreras, 2013, and The Art of Maintaining a Florida Native Landscape, 2015. Check out her blog for the latest news and articles: www.GreenGardeningMatters.com