Written by: Ryley Henninger

As we transition into cooler times, gardens across Colorado begin their slow exhale. Leaves slowly drift to the ground, annual plants give their final blooms, and the rush of the growing season softens into stillness. This season is often seen as the end, but in truth, fall is when life’s next chapter quietly begins beneath the surface. There are new colors, growth, and harvest that we can welcome with a deeper appreciation. Now is a beautiful time to honor one of the most profound and life-giving transitions of the garden: decomposition.

Composting in the fall is more than just a chore or checklist item. It’s a ritual of release, a way to return what is no longer needed back to the earth so it can be remade into nourishment for what’s to come. By embracing this process, gardeners can support soil health, reduce landfill waste, and participate in the sacred cycle of transformation that the garden teaches us so well.

Falling For Decomposition

At its simplest, composting is the controlled breakdown of organic materials (e.g., garden trimmings, food scraps, fallen leaves) into a nutrient-rich soil amendment. Decomposers turn waste into what many call “black gold.” In return, compost improves soil structure, enhances microbial activity, increases water retention, and adds slow-release nutrients for plant health.

Every fall, nature gives gardeners a gift: leaves. Turn autumn’s abundance into garden gold with all the “brown” material. A mature oak can drop more than 200 pounds of leaves in a single season, and those leaves are rich in carbon and trace minerals. While many homeowners bag and discard them, leaves are one of the most accessible and valuable composting materials available. When combined with the “green” material of kitchen scraps or late-season garden waste, they create a beautifully balanced compost blend.

Fallen leaves can also be used to make leaf mold, a slow-composted material that improves soil texture and water-holding capacity. Simply pile leaves in a corner, moisten them occasionally, and let fungi do the work over the course of a year. According to the Cornell Waste Management Institute, this fungal-dominated compost is especially beneficial for flower beds and woodland gardens (Cornell, 2016).

With the change of seasons, garden beds offer plenty of plant material ready for composting, but we must consider our care to avoid introducing disease or pests into the pile. Your compost will thrive with: shredded leaves; grass clippings in moderation; healthy, spent vegetable plants; wilted annuals and flower stalks; fruit and vegetable scraps; and coffee grounds and eggshells. Please avoid composting: diseased or pest-infested plant material; weed seeds or aggressive rhizomes; dairy, meat, and oily foods; and pet waste.

Land Stewardship Amongst the Leaves

Honoring decomposition means honoring life itself. Slowing down to care for this process deepens our connection to the garden, not just as growers, but as caretakers of the unseen.

Beyond the garden, composting is a powerful act of environmental care. Organic materials sent to landfills decompose anaerobically (without oxygen), producing methane, a greenhouse gas over 25 times more potent than carbon dioxide. Composting those same materials aerobically (with oxygen) reduces greenhouse gas emissions and returns carbon to the soil, where it belongs.

Furthermore, a compost pile is more than a heap – it’s a living ecosystem. At the heart of every compost pile is an entire underground world of worms, fungi, beetles, mites, bacteria, and springtails – the sacred workers of decomposition. These often unseen organisms are not pests to be eradicated, but stewards of transformation. Together, they turn death into fertility, refuse into nourishment.

Tips for compost abundance and a winter haven for decomposers:

• Insulate with straw, shredded leaves, or cardboard to retain warmth and moisture. Whole leaves can mat and slow decomposition. Your pile should feel like a wrung-out sponge. Add water if it’s dry, or mix in dry browns if it’s soggy.
• Turn the pile before the freeze, but avoid turning too frequently in winter, which can release heat. Aerating in late fall gives microbes a boost before winter dormancy.
• Add material in layers, keeping a “blanket” of browns on top, while still being mindful of the balance with greens: 3 parts brown, 1 part green (UCANR, 2011).
• Avoid compacting the pile, which limits air flow and disrupts microbial life.
• Consider adding a handful of finished compost or soil when building new layers to inoculate with microbes.

Let nature take her time, and by spring, you’ll uncover a rich compost ready to awaken the soil.

There’s something tender about building a compost pile in the fall. We can witness the vibrant remnants of summer settle into rest, knowing they are becoming the foundation for next year’s life. This season invites us to ask: what can I release? What needs to be broken down to feed the future?

As gardeners, we become caretakers of both growth and decay. We learn to trust in the unseen work of soil microbes, in the slow heat of transformation, and in the power of letting go. Fall composting is not just a sustainable practice – it’s a sacred one.