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October 8, 2025 - Wound Healing Processes

Keeping vegetables healthy after harvest.

As home gardeners know, the journey from planting to harvest is filled with anticipation. Yet, even after a successful growing season, the work isn't quite done. Many common vegetable diseases pose a threat only if they can get past the natural "armour" of the vegetable's skin. Healthy, unstressed vegetables with intact skin are far less likely to succumb to infection. As such, any damage to the skin or tissue creates an open pathway for water loss, which quickly speeds up the decline after harvest and diminishes both quality and lifespan.

So, what can home gardeners do to give their vegetables the best chance against these challenges? According to horticulturist Robert Spencer, there is one overarching strategy. "If you want to thwart successful attacks by pathogens, and to reduce water loss after harvest," Spencer advises, "preserving and maintaining the skin of the vegetable is the best strategy." Potatoes are a really good example, illustrating the link between intact skin and reduced losses from disease or dehydration. However, these same principles apply broadly to most vegetables, including bulb crops like onions and garlic, as well as winter squash and pumpkins. There are various steps that can be taken to proactively encourage intact skin going into storage.

The initial step in this strategy begins at harvest. Avoiding damage to your produce as you pick or dig it is a crucial starting point. For anyone using any mechanical aids, even simple ones, ensure they are properly adjusted and operated to minimize impact. The key is to avoid excessive drops, slamming vegetables around, or bumping them into hard surfaces. It’s easy to think of wounds only as clear holes or penetration of the skin, but Spencer points out a less obvious culprit: "While we might think that a wound has to be a cut or gash, in reality, a bruise is a significant weak point." Even a minor bruise can compromise the skin's integrity, opening the door to problems.

Another vital aspect of this protective strategy involves encouraging your harvested crops to dry down and tighten or toughen their outer layers as much as possible before they go into storage. Bulb crops like onions and garlic benefit immensely from this process. After their tops begin to fall over, lifting them from the soil allows for a natural drying period. Moving these bulbs to a warm, dry area for an extended curing period will further tighten the neck tissues, effectively sealing off this vulnerable area from both moisture loss and potential disease entry. The resulting dry outer scale leaves become tougher, offering better protection for the tender inner tissues.

Potatoes also develop tougher skins once their leafy tops die down. If you choose to remove the tops artificially, perhaps by cutting them back or by pulling them, you can trigger a similar toughening process. However, it is essential to allow a two-week waiting period after the tops are killed before harvesting the potatoes. Harvesting too soon means the skins are still thin and tender, making them much more susceptible to scrapes and scuffs, which are significant weak points.

Some vegetables possess the remarkable ability to repair and replace damaged tissues if given the right conditions. Potatoes, for instance, can quickly begin to lay down tough, reinforced "suberized" layers shortly after their tissues are damaged. These layers act as a seal, protecting the inner tissues from moisture loss and disease attack. If you provide your harvested potatoes with a few weeks of warmer conditions in storage, gradually lowering the temperature each day, this curing period will significantly help them heal any minor wounds. This proactive healing will, in turn, drastically reduce water loss later during storage.

Similarly, giving squash and pumpkins a curing period after harvest can help toughen their skin and dry out any superficial wounds. While some gardeners experiment with rubbing honey on pumpkin wounds to aid healing, a practical step is to gently wipe the vegetables with a disinfectant. This can remove any surface pathogens, hopefully preventing post-harvest infections from taking hold. Store harvested products on a cool, dry surface, preferably not on something that will encourage condensation or transfer of disease (i.e., not on soil).

It is critical to do everything within your power to help your vegetables preserve their skin or repair any holes or injury. Work diligently to prevent injury during harvest and handling and then provide them with the optimal conditions to heal if damage does occur. This attention to the unseen shield of the vegetable's skin is a simple yet powerful investment in a healthier, longer-lasting harvest.