by OCMGA Master Gardeners Barb Dorzweiler and Janet Carlson
True to the name “The Learning Garden”, my team and I learned how to build a lasagna garden in the summer of 2014. We had never built a lasagna garden before, but we were definitely interested and we were up for the challenge. Far from being an expert, but knowing how to find information, I researched a little on the subject before we set out. I referenced the UW Extension publication, A4021 “Making and Using Compost in the Garden.” Yes, there is a science to this. I also referenced another helpful article, “How To Create a Lasagna Garden” by R. J. Ruppenthal originally published in the May/June issue of Urban Farm. First of all, a lasagna garden is a no-till method of building a garden by adding layers of organic materials that will cook down over time not unlike what happens in your compost bins. It can also be referred to as “sheet composting”. We had a designated plot in The Learning Garden and our first step was to dig up two inches of the topsoil on our plot to set it aside for the topmost layer so we could plant right away. The plan was to alternate layers of “green” and “brown” organic materials. Brown materials are rich in carbon and include dry leaves, shredded newspaper, straw, and even shredded toilet paper rolls. Green materials are rich in nitrogen and include green leaves, green grass clippings, coffee grounds, eggshells, fruit and vegetable scraps. Our building happened over two different dates in May in part to give the bed time to cook and because the spring weather was not as warm as we hoped. On May 2nd, we started the bed with a brown layer: straw, compost from the UW-Ext bins and newspaper. The second layer was a green layer of vegetable waste and coffee grounds. The third layer was brown with sawdust and shredded dry leaves. We covered this with a black landscape cloth and left it to warm up for a couple weeks. On May 19th, we added a layer of newspaper and watered it immediately with the garden hose to keep it in place and make it easier to work with. Then again more layers of brown and green materials: dry leaves, grass clipping, coffee grounds (free from Starbucks), and newspaper. Then we added back the topsoil as the topmost layer to use as the planting medium. The lasagna bed was now about 10-12 inches high. Our initial planting was one tomato plant and two rows of lettuce. We labeled our rows with cut venetian blind labels. In later weeks, another tomato plant was added along with carrots, radishes. As expected, the lasagna garden cooked down and lost some of it height. This told us the organic materials were being composted into a fertile, fluffy soil. With the heavy rains this summer, some of the material was washed away, but the mulching around the garden beds helped hold its borders. We were able to harvest bountiful lettuce, tomatoes and the other vegetables. We had concerns that the lack of green grass clippings would slow down the decomposition, but the “green” materials (kitchen scraps and coffee grounds) we used were sufficient so this wasn’t an issue. As we cleaned up for the fall, this wonderfully fertile, loose soil can be spread and used over the adjacent garden plots or added to for another lasagna garden. It’s definitely a sustainable way to keep your organic material out of the landfill and improve your soil at the same time. I definitely recommend this process. On to next year’s plans; what will the next team do? It was a fun and learning experience for us!
Reprinted from the OCMGA member newsletter from the winter of 2014