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Q:  What is the typical success rate for vegetable grafting?

A:  Although variation occurs across vegetable types, tomato and cucurbit grafting can be carried out with great success (85-95%) very easily.  This process requires the union of two equivalent stems and the proper environment for healing and re-acclimation. Although we have had some grafting failures (~50%), most of our batches of grafted tomatoes have success rates >95%.  For more information about tomato grafting technique, click here.      

Q:  How much time is required for grafting?

A:  Commercial graft producers using the Japanese top-grafting method are able to make approximately 800-1000 grafts/day.  In our lab, we typically make 200-500 grafts in 3-4 hours, and an experienced grafter can process ~200 plants per hour.  Once grafting has occurred, expect an extra 2 weeks for healing and re-acclimation before transplanting into the field.  For a printable grafting guide, click here.

Q:  Can the use of grafted vegetables increase yields even during years that disease pressure may be low?

A.  Many commercially-available hybrid rootstock varieties are able to increase plant vigor, thereby increasing yield even in cases where little disease pressure is evident.  This increase in yield may be beneficial in order to offset the costs of grafting.  However, it’s not clear that this occurs in all cases.  Rootstock/scion combinations and cultural management can impact the utility of added vigor from rootstocks.

Q:  How costly is tomato grafting?

A:  Additional labor, grafting clips, and rootstock seed may add to on-farm costs.  Although this process is laborious, small growers (<1000 plants) should not see large effects from labor.  Many larger graft production facilities are integrating robots in order to increase throughput.  Grafting clips are $.07 - $.10/piece, but can be easily recycled if they are collected and sterilized before the next use.  Hybrid rootstock seed is also costly.  However, for heirloom growers, the use of modern hybrids (e.g. ‘better boy’, ‘roma’, etc) may have similar disease resistance when utilized as a rootstock.  These varieties may not include the broad spectrum disease resistance and increased yields like many rootstock-specific varieties, but could be significantly less costly.  In all of these cases, it is likely the costs associated with grafting will decrease as this technology is better assimilated into American agricultural production.  For more info on transplant costs see the project report from Black River Organic Farm     

Q:  What rootstock should I use?

A:  Many rootstock-specific hybrids have been developed in Asian and European countries and some of these are available in the US.  Rootstock selection is a site-specific recommendation for individual growers with different soilborne disease profiles.  For more information on rootstock selection, click here.