Vine Nutrition after the Polar Vortex

Tuesday, June 27, 2023

Now that things have started to grow people are wondering if they should be adding fertilizer to stimulate recovery where vines are showing some growth and even potential for some crop (hybrids). If you have prior soil and tissue sample results, use these as a starting point in nutrient plan post bloom.

Vine nutrient additions will not fix a severely affected vine from polar vortex injury.  Your decision to fertilize should be based on vine conditions across the block. Consider categorizing blocks into the following groups to support your decision making:

  1. Are the vines showing reasonably full canopy growth with visible fruit clusters?  These vines would be considered in Recovery with potential crop mode. These vines would have 50% or greater primary bud survival
  2. Vines are showing multiple shoot growth around the head area of the vine along with some sucker growth but has limited canopy growth from buds on canes left from winter pruning. These vines would have 25 % or more primary bud survival.
  3. Vines have less than 10% primary bud survival and have multiple suckers originating from the base of the vine in an attempt to keep the vine alive.
  4. Vines show limited top bud break and few suckers (<2 per vine) from the base of the vines.  

Adding nutrients in the case of Group 1 above can take place but need not be applied until after fruit set. At that point you can determine the amount of crop you might expect from primary and secondary clusters and modify your normal program accordingly.  From experience, smaller crops that receive too much fertilizer often have delayed harvest dates, poor vine maturity, poor cane maturity and often more winter damage the next year. I would recommend no more than 50% of normal fertilizer use in 2023 immediately post bloom to allow enough time for nutrient mineralization and uptake by the vine to allow for growth and vine maturation in fall 2023.

A vine showing reasonable top growth that should be bearing fruit this year.

If blocks are in Group 2 and 3 above, the soil reserves are likely adequate to allow for proper vine growth this season without additional fertilizer.  The key is to watch for any potential symptoms of deficiencies and manage accordingly.  In some cases, if you have historical soil and tissue analyses for these blocks you may know of any inherent soil deficiencies and applications of elements OTHER THAN NITROGEN, can be used at a max 25% of traditional rates. Elements to look at would be potassium, magnesium, and micronutrients and likely would only apply products if visible leaf deficiencies are observed.  I do not recommend any nitrogen (soil or foliar) in these groups as this is the equivalent of “painting wet wood”. Makes you feel nice but won’t last, won’t help, and just adds to your expenses in 2023.    

A vine showing good head renewal.

Multiple suckers originating from the base of the vine.

For Groups 1, 2, and 3, recognize the objective is to assist with vine recovery and renewal and to support the root system in place. The root system especially on mature vines needs carbohydrates produced by the leaves to survive so over cropping can harm the vine as excessive nutrient applications can lead to soft top growth that is not very winter hardy.

For Group 4, minimize competition (weed growth around suckers and beneath the vine) and there is no need for any fertilizers. This is a wait and see proposition for vine survival. 

Your primary objectives in 2023 is to keep the vine in balance, to ripen the crop if present, to feed and sustain the root system with the objective of vine recovery and/or reestablishment of new trunks for 2024 and ideally excellent maturation to withstand the winter of 2023/2024.