Use plant rooting hormone rooting solutions by the Basal Long Soak Method.
This method is useful to propagate many plants from cuttings that are difficult to propagate by other methods.
It is especially useful where rooting by basal methods at high rates are variable in root formation.
You can use Hortus IBA Water Soluble Salts.

Measure Salts and mix with water.

Wine grape hardwood cuttings develop the best root formation when they are propagated using Hortus IBA Water Soluble Salts rooting solutions by the basal long soak method.

You make your own rooting solutions using Hortus IBA Water Soluble Salts

First the grape cuttings are prepared.
Grapes are propagated using the stenting technique where the cuttings are grafted and rooted simultaneously.
After preparation, the cuttings are placed, basal end down, in a plastic treatment tank.

This demonstration uses a treatment tank that takes 100 liters of rooting solution.

To root grape cuttings, use a rooting solution containing Hortus IBA Water Soluble Salts at 80 to 400 ppm IBA. The rate varies based upon the species or variety.

Pour the rooting solution into the treatment tank. The rooting solution must cover the basal ends of all the cuttings to a depth from 2 to 5 cm. Adjust the tank to the horizontal position so that all cuttings are at uniform depth in the solution.

Let the basal ends of the cuttings soak in the rooting solution between 12 and 48 hours.

Let us look inside the grape cuttings:

Hortus IBA Water Soluble Salts rooting solutions contain forming substances called auxins.
The cuttings absorb the auxins into the basal end where they are stored.
The plant uses the auxins by re-programming the plant cells at the basal end of the cuttings. These cell become new root cells.

After Hortus IBA Water Soluble Salts rooting solution treatment you plant the cuttings in media.
Symmetric roots, with high root mass, will soon form around the basal end of the cuttings.

Hortus IBA Water Soluble Salts rooting solution treated grape cuttings develop a high root mass and a symmetric root system. These cuttings produce fine quality plants that will have decades of grape production.

Every grower has different needs. It is important that you do trials at your own growing facility so you can find your optimum methods and concentrations.
Rhizopon is glad to help you with your growing program so you best benefit from Rhizopon plant rooting products.