In case you didn’t add mycorrhizal fungi when your vines were planted, the good news is that its not too late, and is easy to do with this water soluble formula. Mycorrihizal fungi send filaments off of plant roots to extend the water and nutrient uptake of roots. Cool stuff. https://www.pacifichorticulture.org/articles/mycorrhizal-fungi-natures-key-to-plant-survival-and-success/

Here is a wettable version for sale that is very popular with high end farmers and growers: https://www.groworganic.com/products/mykos-mycorrhizae-wp-22-lb?_pos=4&_psq=my&_ss=e&_v=1.0

And if you want to further improve soil health, adding humus can dial things up. The liquid form Humax is easy to apply around vines and plants.

https://www.groworganic.com/blogs/articles/how-to-use-soil-amendments-humates-humic-acids-and-humus?_pos=1&_psq=humus&_ss=e&_v=1.0