Week 8 (Aug. 5 - 9th)

After two weeks off I am back at the HRC. I spent my first week getting to know the mosquitoes of the Boundary Waters. My brother, a friend, and I canoed for five days near the Gunflint Trail and then hurried back home just in time to leave for a family adventure. The six of us left the next morning and road-tripped across the plains of SD to the Black Hills. We then spent the next six days backpacking the Bighorn Mountains of Wyoming. I fly fished the whole time, while the others relaxed and soaked up the serenity of the wilderness.

Both trips were exhilarating, but I am glad to be back to my normal schedule again. Lucky for me, this period of the summer is one of the slowest for grapes, so I didn't miss a thing! The rest of the grape crew actually spent the two weeks helping the apple guys "bud" new trees.

Since we all were away, this week was devoted to tidying up the vineyard. We spent three full days strolling through all the rows skirting, suckering, combing and mowing as we went. This was a good chance for me to check back in and observe the progress that had occurred while I was away. I noticed that the grapes had expanded in size tremendously and that some clusters had even changed colors. The process of a cluster changing color is called véraison. All red grapes go through this process, while white grapes just get a little warmer in color as they ripen. It appeared to me that the grapes with more of a V. riparia background were much farther along in this process than the rest. 

véraison = the onset of color

The birds are quick to notice the color change in the grapes as well. Birds use this visual cue to determine that the grapes are ready to be eaten, generally waiting until the grapes reach 22 Brix. Therefore, we have started to net the grapes that have changed colors. This will be a continuous task for the next few weeks as more varieties reach veraison.

Vines that exhibit excessive vegetative growth may benefit from a "kicker cane" such as this along the bottom wire. Since this cane is closer to the roots it is first in line to receive nutrient supplies and therefore it grows faster than the shoots along the cordon. This nutrient sink "bull cane" will be pruned off as soon as the berries hit veraison. 

A Japanese Beetle. This invasive species, introduced to the US in the early 1900s, is problematic for grape growers all over the Midwest. Once the canopy is defoliated more than 5% growers typically spray the vines with an insecticide. This can get tricky, since some sprays cannot be applied after 60 days before harvest for health reasons. 

On Friday we decided to have a little fun with the grape crew and toured two local vineyards. During these tours of Sovereign Estate and Parley Lake Peter and John gave various tips and suggestions to the other growers along the way. For example, the pattern displayed in the leaf above is indicative of a potassium deficiency. We found this problem in many low-lying areas of their vineyard. We also found areas where leaves were turning yellow, but their veins remained a pea green color. This symptom was caused by a lack of iron in the soil. John suggested that their manager draw a map of the vineyard and note problems like this so that he can resolve them next spring. 

Week 7 (July 15 - 19th)

Over the past few weeks I have noticed that in the mornings some vines have water droplets like this on the tips of their leaves. These droplets are generally found in the morning near the ground. This happens when the water is exuded from secretory tissues called hydathodes, pores found in aquatic and some herbaceous plants. It is most likely in these vines the water is being forced out of the hydathodes, instead of passively flowing out of the stomata, because the humidity near the ground is too high for evaporation to happen. 

This is a classic example of a vine trellised on the J-system. All of our V. vinifera grape vines, which you can see by the hanging bags were used in our breeding program, and non cold-hardy cultivars are grown this special way so that their canes and buds can survive the winter. Most of these species can only handle temperatures down to -8F. Therefore, every November J-system vines are unhooked from the wires, pruned and buried under dirt and straw. This vine happens to be a Riesling. 

One of this week's larger tasks was to tape the nursery vines to their bamboo stakes. This was a muddy, but fun, job that took us most of a day. During the process we also removed lateral shoots in order for the vines to focus their energy and nutrients into one main shoot. This "plumper" vine will be a greater storage of carbohydrates and nutrients for when these little guys are planted in the vineyard next year.

The goal of "combing" is to open up the canopy in order to increase airflow and expose the leaves within the canopy to the sun. This is important for the overall productivity of the plant, since any leaf that is in the shade is effectively a resource sink, not source. This practice of re-positioning the shoots also allows the fruit to be exposed to the sun, which will allow them to ripen faster. We are now starting to focus on the progress of the fruit growth instead of the shoot growth. We have made it through the lag period, meaning the fruit is starting to expand again.