The Lasagna gardening method is effective in all four seasons, but cold climates reduce microbial action. I have clients who garden in Minnesota who can dictate the layers in -20°F winters using summative strategies. Pre-composted "greens" in a cold layer, insulating strategies keeping beds active even in winter, snow-covered conditions. The fundamental success key is nitrogen layers and controlling the sizes of layers for successful composting.
Heat-Boosting Techniques
- Pre-compost greens in sealed bins for 2 weeks pre-layering
- Bury 1" chicken manure pellets every 6" depth
- Cover beds with black landscape fabric until snowfall
- Mix 10% finished compost as microbial starter
Material Modifications
- Shred leaves to 1" pieces using lawn mower
- Replace straw with spent grain from breweries
- Soak cardboard in compost tea before layering
- Add 2" coffee grounds between every brown layer
Use a 24" compost thermometer to monitor internal temperatures. Aim for ideal temperatures in the 90°F to 110°F range even in air temperatures below freezing. For example, my Alberta bed hit 104°F in January because it had layers of manure and was wrapped in burlap. Turn the beds if they cool down below 80°F for more than 48 hours or the composting process will stop.
Slow Decomposition
- Insert perforated PVC pipes for airflow
- Add 1 cup sugar water per sq ft to feed microbes
- Layer snow instead of removing it (insulation)
Odor Control
- Mix pine needles into soggy layers
- Sprinkle bokashi bran every 12"
- Avoid meat/dairy in pre-compost phases
Methods for extreme cold need to be combined. A Vermont client wrapped the beds with geotextile blankets over plastic, to mimic a greenhouse effect. They had decomposed their lasagna layers, growing food at a chilly -30°F, the entire time. Layering and strategy always beat the raw climatic conditions.
Read the full article: Lasagna Gardening Method: 10 Essential Steps for Success
