Mulch and compost are critical in winter. The mulch keeps delicate roots of less cold hearty species healthy and warm, and the compost both holds and produces moisture to attract life from below. In the planters, compost fertilizes the soil, while the cover locks in moisture. The covers and the fresh layer of mulch give the gardens a “cared for” look.
In my opinion, one should always be fertilizing and preparing both for the present time, and 18 months ahead. Those six seasons matter. Just-in-time prep looks great on paper (and night “work” for a suburban garden or Walmart) but it will not support and maintain a healthy ecosystem. You have to not only replenish and protect in the winter, you must also stock the larder for the coming freeze/thaw cycle. When nature’s blind biofeedback system is activated, you actually get a far, far healthier ecosystem that is far more resilient than a just in time system in heat stress and cold stress.
Mezzacello is not a just-in-time ecosystem. It is a collection of ecosystems that need to be both sustainable, inter-related, and self-sufficient. In nature this achieved through water, freeze, entropy, animal prey and predation, insects, and bio wastes. On an urban farm, all of that has to be generated. It’s easy enough; don’t be stingy. Factor in 30% going back into the earth right off the top. That’s the cost of doing business. Trying to cheat an ecosystem is a fools errand.