Southwest Yard and Garden; Spring planting and care for grapevines
1. How big should the planting hole be?
The hole pictured above is about two feet wide and deep—perhaps a bit of overkill—but the hole should be big enough to accommodate the roots and provide adequate space. This wide hole will help to prevent the dreaded “J-rooting,” when the vine’s longer roots get bent into a J shape to fit the hole and will likely never thrive and will die prematurely.
Use the same soil you dug out to fill the hole, without any amendments. After planting, the graft union should end up about four inches above the settled soil line.
Adding fertilizer to the planting hole is not advised when planting bareroot or potted grapevines. Wait two– three years until the vine gets established and add a complete liquid fertilizer only if needed. Always be sure toread labels and follow directions. Remember that the European cultivars like our alkaline (high pH) soils but the American types do not. The latter will likely benefit from a chelated iron product since iron is minimally available in high pH soils.
2. How do I “line up” the new vines in a row?
between line posts, with plastic flagging tape tied at four-foot intervals to mark where holes should be dug (see photo above). This method allows almost perfect alignment and spacing of newly planted vines without getting in the way of the process.
3. How cold hardy are different types/species?
There are many types and species of grapes that can be successfully cultured in the home garden/vineyard. The most vulnerable or least cold hardy are the European grapes Vitis vinifera, the grape that is most common for wine grapes (Cabernet Sauvignon, Chardonnay, etc.) and many popular seedless table grapes (Thompson Seedless, Princess, etc.). Concord and Niagara are popular “American” grapes and are of the Vitis labruscana species. And then there are hybrids. American types are the most cold-hardy and hybrids are intermediate between American and European types.
Visit the blog version of this column for a chart showing the variable cold hardiness of various cultivars (https://nmsudesertblooms.bl ogspot.com). Also visit the blog by NMSU Extension Viticulture Specialist Dr. Gill Giese to follow grape research projects around the state (https://nmsuloslunasasc.blogspot.com). For more information on cultivars recommended for New Mexico, check out the recently revised NMSU Extension Guide H-309, “Grape Varieties for North-central New Mexico,” at https://aces.nmsu.edu/pubs/_h/H309/welcome.html.
4. Should I use grow tubes?
Grow tubes are usually white or other colored plastic and a foot or so tall. There are advantages and disadvantages to using grow tubes. Many commercial growers use the tubes to protect the young vines from herbicides they apply to control weeds. This is the main reason for their use in that setting. If you can control the weeds manually without damaging the trunks with weed whackers, the grow tubes are not necessary. “Weed eater” disease, as it’s called, is a death sentence. Below are some advantages and disadvantages listed for consideration:
• Increased vine growth via:
• Increased temperatures when ambient temperatures are cool
• Protection from the wind
• Protection from critters
• Protection from herbicide spray (and reduction in labor costs)
• Decreased water use requirement
• Some are reusable
• High temperatures may melt wax on grafted vines and could compromise the graft union
• Diseases and insects can proliferate in tubes and be hidden from view. For this reason, some nurseries will not guarantee plants when grow tubes are used.
• Weeds in tubes can be a hassle because they’re hard to access
Guest author Dr. Gill Giese (NMSU Extension Viticulture Specialist) and regular author Dr. Marisa Thompson (NMSU Extension Horticulture Specialist) are both based at the NMSU Agricultural Science Center at Los Lunas.
For more gardening information, including decades of archived Southwest Yard & Garden columns, visit the NMSU Extension Horticulture page (http://desertblooms.nmsu.edu/), follow us on social media (@NMDesertBlooms), or contact your County Extension office (https://aces.nmsu.edu/count y).