And so we enter another warming trend for the weekend and beginning of next week. Then, it will get burn-your-nostrils cold again. Growers across Ohio and the rest of the Northeastern United States have already evaluated bud damage in their vineyards from the first polar vortex that rolled through town the week of January 6. The results from most vineyards are grim. Very grim. And we still need to make it through the rest of the winter, which is a solid 6 weeks to go. Maybe more.
So what’s a grower to do? Grab a glass of wine and hunker down with last year’s soil test results, of course. Now is a good time to make some plans for 2014 nutrition management in the vineyard*. Just as animals require vitamins and minerals, plants – especially cultivated plants, such as grapes, apples, peaches, raspberries, wheat, corn…you get the idea, also require nutrients to maintain a healthy crop. Monitoring soil and vine health can be as easy as regularly testing vineyard soils and grapevine petioles. Once these results are in hand, a grower can use these test results to evaluate soil and vine nutrients and calculate what amendments, if any, are needed.
Growers can work with local viticulture extension educators to calculate amounts needed to bring soil levels to those within the ranges listed in the table in Figure 1. As a quick example, let’s take a look at a soil test result (Figure 2).
First, it is important to note the soil pH, which is critical in vineyard nutrient absorption. Grapevines are most efficient at a soil pH between 6.0 and 6.5, so sites will need to be amended prior to planting, whether lime or sulfur is applied. Lime will increase soil pH, and sulfur will decrease it. In our example, the soil pH is 4.7, so lime is the most important nutrient needed in this vineyard. In fact, in a year like 2014, the best investment for this grower in 2014 might just be lime in this block.
The next red flag in this soil test result is that the soil organic matter is low – 1.7%, but it should be be tween 3%-5%. This grower could work to build organic matter, either by adding compost or mulch, or even planting a cover crop, which then would be controlled with a pre- or post-emergent herbicide. This can build soil organic matter, which can then improve vine health.
An extension educator can work with this grower to go through the rest of the nutrients to assess what nutrient amendments could be added to the vineyard represented by this test result. From there, this grower could decide which amendments would result in the most bang for the buck. Again, for this year, working toward adjusting the soil pH might be the best strategy, considering there will likely be a very light crop this year. If vines appear to have nitrogen deficiency, then perhaps a foliar feed could beef up vines just for this year. For more information on managing vineyard nutrition, refer to eXtension.org’s Grape Pages.
For representative results, follow appropriate soil and petiole testing guidelines, and submit samples to any of the analysis labs listed at the end of this post. There are other laboratories that do soil and petiole testing, but these listed might be the most appropriate for growers in Ohio.
Grape Tissue Analysis Labs**
*Of course, if there truly is as much damage and crop loss as seems apparent now, growers would be better off to spend money on a minimal nutrition plan and beef up weed management. This means, possibly cutting nitrogen altogether, depending on soil organic matter, and applying other nutrients ONLY IF the soil tests indicated a deficiency AND IF the vines showed symptoms of a deficiency during last season. Reducing weed competition can increase water and nutrient absorption by grape roots, which can help the vine recover enough to develop a large crop for 2015.
**There are certainly more labs in Ohio and across the US. We do not promote any particular soil testing lab over any others. Individuals should choose the lab that best suits their needs, depending on location, personnel, or economics.