Vegetable Grafting: The Healing Chamber
High value vegetable crops such as eggplant, heirloom tomato, and triploid watermelon are grafted to increase vigor, yield, tolerance to salinity and temperature extremes, and disease resistance. Commercial production and demand for grafted vegetable plants continues to increase across Asia and Europe, and has begun to expand to North America.
It takes an average of 5–8 days after grafting for the rootstock and scion (top of grafted plant) to establish vascular connection and 14 days for the graft union to fully heal. During the first week after grafting, the scion is unable to receive water from the rootstock. It is therefore important to maintain proper environmental conditions to prevent water loss from the scion and promote rapid formation of the graft union.
A healing chamber is a small covered structure that maximizes humidity and reduces light to allow grafted plants to heal. The primary purpose of the healing chamber is to minimize transpiration (water loss) from the scion. The size and design of the healing chamber depends on the scale of production of grafted plants. A home gardener can create a small healing chamber from a seedling flat, a plastic propagation dome, and a large black plastic bag, but commercial growers may need a larger healing chamber to accommodate larger numbers of plants.
There is currently limited information available on healing chamber design and use. This fact sheet provides step-by-step instructions for constructing and managing a healing chamber.