So what is lasagna gardening? It is a technique that involves strategically layering organic material that will decompose to create a rich growing material. This could also be called a horizontal compost pile.
It is an inexpensive way to get good soil out of a dirt field, grass or weed infested area. Because this is a type of compost the ground heats up during the process therefore killing existing plant materials like turf grass or weeds. It could also be called a horizontal compost pile.
This technique can be used on a large area of dirt that you’d like to plant a vegetable garden in come Spring, it could also be used to replace your existing high water turf grass with a perennial garden. A lasagna garden can heat up enough to kill weed seeds and grass.
Brown materials: Cardboard, newspapers, junk mail, leaves
Green materials: Manure, veggie scraps, coffee grounds
Fall is the perfect time to build your lasagna garden due to all the materials readily available! After you have collected all your materials you can begin the layering process. Simply layer brown materials then green materials making sure the brown materials are twice as high. Watering after each layer.
1. Prepare the surface: There are two basic options for preparing the surface. You can dig down into the ground and have a level planting area that will easily harvest water or you can simply place the layers on top of your existing poor soil. This might be an existing grass area you want to remove or existing weedy dirt are you want to improve. Being, I live in the Southwest with little rainfall, I tend to dig my lasagna gardens 8” into the ground to take advantage of collecting water.
2. Layer cardboard and wet: Once you have prepared your area you can place the cardboard, layering one layer thick with a 2’ overlap. I prefer to use cardboard for this which can easily be sourced from cardboard recycling bins. You may also use a thick layer of newspaper, or split up phone books. This will be the hottest layer that will kill the undesirable materials. Wet, even soak the cardboard before applying the next layer.
3. Layer manure and wet: Add horse manure (chicken poop can also work) completely covering the cardboard. Most horse stables will have piles of manure available for the public for free. A few phone calls should do the trick. Wet down the manure before proceeding to the next layer. You can also add food scraps and other green materials to this layer but this is not necessary.
4. Layer brown materials and wet: Add the leaves, hay, pine needles or other yard debris to this layer, stacking it twice as high as the manure layer.
5. Repeat manure layer, brown materials layer and wet: Repeat step 3 and 4. After you have completed these steps your pile will be around 8-12” tall, don’t worry over time it will compact down to 4-6”.
6. Watch, water and wait: The final step is waiting; this process can take up to 6 months. Over that time the materials will decompose. For dry climates, I recommend keeping the pile moist which might require watering 2 times a week. A continued moist pile will decompose faster. If after two months you don’t see much change happening you might need to get your pile hotter. You can do this by adding a piece of black plastic (like yard garbage bags) to the top of the pile. A week of the plastic will aid in heating the pile up. Now just wait and check the pile for the next six or so months.
Remember that just like every human is different, every lasagna garden is different so experiment and enjoy the experience. You’ll be pleased with the results!