Wine grape vines are susceptible to the soil parasite Phylloxera, and must be grafted onto resistant rootstock to prevent infection.

The lower lying areas of the vineyard contain the rich and fertile soils needed to produce healthy rootstock canes. The rootstock grows untrellised throughout the year, and is harvested once the plants are dormant (generally beginning in December).

After the rootstock canes are harvested, they are stripped of sideshoots and tendrils, cut into 14 inch segments for grafting, and sorted into groups based on their diameter.

Santos Espinoza, Assistant Nursery Manager, bundles 100 units of 3309C rootstock prior to a sterilization dip.

The sized, bundled and sanitized rootstocks are inspected by nursery crew members before being bagged and labeled. The bagged rootstocks are then placed in cold storage until they are needed for grafting.

The vinifera (wine grape) vines are pruned beginning in mid-January, and are cut into 5 bud units. Like the rootstock, the vinifera budwood is cleaned, sized, bundled, and sanitized before being placed in the cold storage facility to await the beginning of grafting.

The grafting season begins in February with the immersion of the rootstock and vinifera canes in water in large plastic bins to rehydrate.

Once the vinifera is fully rehydrated, it is cut into one-bud sections in preparation for grafting. The rehydrated rootstocks canes are disbudded to discourage growth of the rootstock itself, and left at 14 inches in length.

Grafting is completed using omega grafting machines, which join the vinifera buds to the rootstock canes like two pieces of a jigsaw puzzle.

The vinifera bud is cut first. The grafting machine holds onto the vinifera bud while the rootstock cane is cut with a second movement, and the two are joined together.

Here is a sample of a newly grafted vine.

Newly grafted vines are layered in boxes containing vermiculite, perlite, and peat moss.

The boxed vines are then placed in the callus room, which is kept at 85% humidity and 85° Fahrenheit. Under these conditions, if the graft has been successful, callus tissue will begin to form at the site of the graft union, and roots will begin to develop on the non-grafted end of the rootstock cane. The vines remain in the callus room for three to four weeks.

The vines come out of the callus room, and are sorted. Development of a callus at the graft union ensures the viability of grafted vines.

Vines with significant calluses are dipped in wax to insulate the young grafted vine. Unsuccessful grafts are discarded.

After the wax dip the callused grafted vines are planted in pots containing a soil-less media mix composed primarily of peat moss and moved into one of three high-tech greenhouses with computer-controlled temperature and humidity.

After one to two weeks in the controlled greenhouse environment, the leaf of the vinifera bud bursts through the wax cap and begins growing.

After four to six weeks in the greenhouse, good root structure is established, and the vine thrives. An ongoing program of trimming the vinifera encourages full and strong growth of the roots while also maintaining good development in the vinifera portion of the vine.

Under the care of our nursery staff, the greenhouses and screenhouses are full of thriving grafted vines.

As the vines reach maturity, they are moved out of the controlled environment of the greenhouse and into one of the several open-air screenhouses. In these facilities, the plants are "hardened off" or acclimated to the sun and exterior elements.

After two weeks under moderate shading, the plants are moved to full sunlight. By early June, the vines have healthy root systems and good leaf development, and they are ready to be shipped to the nursery's clients or planted on the Tablas Creek estate.

To view nursery Vinifera Budwood and grafted vine purchasing information from our partner NovaVine, click here.