Grapegrowers across Napa, Sonoma, and Mendocino counties are doing their best to stay on top of the essential canopy management work that needs to be done in vineyards. After the late start to the season and then rapid growth after the weather warmed in late April, all vineyards need to be suckered and positioned at the same time. California is also experiencing a shortage of labor making it particularly difficult to get all the work completed.
The rapid growth was accompanied by strong growth of suckers, growing positions along the vine that are not intended for fruit production. Once growers get around to suckering, they are seeing that the intended positions may have grown less weak and more variable than they would like to see. The suckers really pulled a lot of energy from the ‘count’ shoots this year. If you have a lot of variability in shoot length, it may be worthwhile to tip the long shoots to stimulate growth into the weaker shoots.
Also, growth has slowed and many shoots are not seeing full extension, but flowers are starting to bloom. We may not see as much canopy development as we would hope for, coupled with some variability, and this will have to be addressed at fruit thinning if we have a good set. And in the weakest blocks, it may make sense to fertilize if you haven’t already, but be careful because water and fertilizer at this stage may push vine growth at the expense of a good set.
On a positive note, bloom has begun! And the weather has been perfect for a good set. After two low yielding vintages, it would be nice to have a good set, and if we need to do extra thinning, that would be better than not having enough fruit. The lovely weather has caused the period from budbreak to bloom to be shorter than average, and we are catching up on our grapevine phenology which is good since another late vintage could bring rains before ripeness.
As if suckering was the only thing going on! Everyone is preparing or applying their bloom sprays. It is a good idea to put a mildew protectant, a Botrytis protectant, and some foliar nutrients like boron and zinc, which will help with set. Some vineyards are in the Napa County quarantine for the European Grapevine moth and need to add an insecticide to try to eradicate this pest.
Weed control is still an important activity. Many people are making their second weedeating, mowing, and cultivation passes. And as soon as suckering and positioning is complete, we will have gone through set and will need to pull laterals and possibly leaves around the clusters to allow for air and sunlight to dapple the grapes.
A final reminder- the next few weeks are the time to take your vine tissue nutrient samples to send to the lab for analysis. Bloom is the best time for that, and the earlier you get your results returned from the lab, the quicker you can address any deficiencies and apply any fertilizers necessary.
All in all, the vines look healthy, we are optimistic for a good set, and less vegetative growth can be a positive thing for less canopy management and better ripening if the vines are not overcropped. So, despite my concern over shoot length and variability, I am enthusiastic about what I see.
Cliff Lede Winemaker Kale Anderson in a 1946 heritage planting of Sauvignon Vert
Esteemed viticultural consultant Bob Gallagher said to me this week, ‘We spend our time waiting and trying to keep the crews busy all winter and early spring, and then all of a sudden we are two weeks behind!’ This couldn’t be truer, especially in a year like this, when we had nice April rains that broke into this warm and sunny weather. The vines have been growing so rapidly! The weekend of April 21st and this week we’ve even had temperatures in the 90s.
Earlier budbreak varieties started early, but barely grew in March and most of April, and so it seems that varietals that budded out later are not far behind. Almost every vine I look at has about 12-18 inches of vegetative growth and needs SUCKERING! Damn suckers!
Suckers are shoots that are growing any place on the vine that you didn’t intend and don’t want them to grow. When we prune, we leave a certain number of buds from the prior year’s growth, and those are intended to produce shoots and fruit in the coming season. Any growth from the trunk, along a cordon, a second shoot growing from the same bud, in a crowded area of the head of the vine, should be removed, and this process is called suckering!
It is best to prioritize suckering of young vines, weak vines, and cane pruned vines (otherwise you can see a lot of apical dominance and the shoots near the head grow weakly which is not good since these shoots become the canes to select from for next year’s canes). Lower priority is high vigor blocks that can benefit from more growing points slowing down overall vine growth.
It’s not just the vines that awaken in the spring. So do the pests such as thrips, mealybugs, mites, and little vertebrate varmints. Keep an eye out for these guys! Look for spider mites underneath the leaf in the cracks of the vein near the leaf attachment to the petiole. Erinium mites are more obvious as their blistering of the leaf is a classic and obvious symptom. Mealybugs are just starting to move onto leaves, but are more likely found underneath bark on the cordon or on a spur position. Thrips are often found on the shoot tips and can cause a classic distortion of the leaf shape, like a cup, and a black color on the leaf margins. Voles and gophers make obvious signs along the ground.
Any of these pests can be tolerated to a certain degree, so you need to keep an eye on their predators and look for a balance. If the quantity exceeds tolerable levels, then there are many options to address this lack of balance. Call me if you want to discuss!
Because we received significant rainfall recently, the cover crops grew rapidly at the end of the season, and need to be mowed AGAIN! Also, it’s time to begin your mildew prevention program if you haven’t already. So crews are busy dividing their time between suckering, mowing, cultivating, and spraying.
This year, May 1 marked the transition from our mellow time to the crazy time of the year, and the transition from mud to dust!
Wet weather continued this past week, further delaying budbreak. At this point, we are even a few days behind 2011, one of the latest budbreaks in recent history. The earliest blocks have 3 to 5 inches of growth, but some of the later blocks are just starting to push buds out.
Last week, we experienced some frosty mornings, but in most areas temperatures did not creep below 31°, and damage was limited to a few singed leaves. The wetter weather this week has allowed growers who were up all night turning on wind machines and sprinklers to catch back up on much needed sleep.
Fortunately, we are starting the season with a fully drenched soil profile, which will allow the vines to build strong canopies. Hopefully, the rain will stop soon so the canopies don’t experience excessive vegetative growth.
The rain and slow vine growth has delayed vineyard operations. Some growers have had a chance to mow their cover crops between the periods of unsettled weather. If the cover crop is perennial, it makes sense to not mow again or to delay mowing until the cover goes to seed.
Although it is best to reduce the amount of cultivation in soils to build healthier soils and reduce erosion and soil run-off, young blocks or very low vigor sites may benefit from cultivation to reduce the competition from the cover crop. Hillsides should wait until the rainy season is over, and many Napa vineyards have ordinances preventing hillside cultivation until after April 15.
The earliest blocks are ready for their first mildew prevention spray. Although it is common and acceptable to use a wettable sulfur and copper to start the season, I think it is even better to use oil sprays in the first few sprays. Sulfur needs heat to activate and the cooler weather we are having will cause the sulfur to be less effective. Plus, oil has efficacy against mites and thrips, which I have already seen on some young leaves.
Voles and other rodents have been an increasing concern in Napa vineyards in recent years with wet springs. As soon as the ground dries out enough and we get some warmer weather, I expect to see these varmints. It is good to start trapping earlier in the season before they begin their reproduction, so keep an eye out for voles.
The warmer weather forecasted for next week should really push vine growth into full gear and we'll be busy mowing, spraying, and suckering!
Please share your thoughts and observations- frost damage, insect sightings, etc. We welcome an interactive dialogue!
Although the vines started to grow early this year, the recent cool and unsettled weather has slowed and extended budbreak. The most advanced blocks, such as Chardonnay in Carneros, are almost fully out, but many blocks are just experiencing bud swell.
The delay is welcome in that the later we experience budbreak, the less likely we will experience frost as we move into the later months of spring. And this unsettled weather has minimized frosty nights recently. Moreover, the rain is much needed since we have received only about half of an average year’s rainfall thus far. The forecast calls for more unsettled weather, which is promising, especially if it comes now and then clears up for late spring.
As pruning is nearing completion, we are in a bit of a waiting period for vineyard operations. If the ground is dry enough, now is a good time to mow.
In Napa County, growers are putting out mating disruption dispensers for the European Grapevine moth, as we are still trying to eradicate this invasive pest. This is an environmentally-friendly way of combating these insects as these dispensers emit mating pheromones throughout the vineyard and confuse the insects and make it nearly impossible for them to find actual mates. This mating disruption will be paired with two or more insecticidal sprays that are targeted specifically for this pest and have minimal non-target mortality, and the hope is that this year we can eradicate this pest from Napa.
The next major vineyard operation will be suckering, when we remove shoots that are growing out from the trunk or other positions that were not left intentionally during pruning. This is usually done once budbreak is complete and the shoots are at least 4” long, but before they begin to lignify and become difficult to remove by hand.
Growers also need to plan their first mildew prevention spray. This should also occur when shoots have reached 2-6” of growth, but may be delayed in lower pressure sites.
This is always an exciting time of year, when the energy of spring brings the promise of a new season and we anticipate another unique vintage.
Growers have been challenged in 2011 and 2010 with wet springs that make it difficult to control vine vigor as well as fungal diseases such as powdery mildew and Botrytis. Canopy management and disease prevention costs were high. It would be a relief to growers to not have to repeat those challenges and have better control over vine vigor in 2012, if, and only if, there is significant water to sustain the vines through any extreme periods of heat and to establish young vines in this era of significant replanting. Although vines can live with minimal irrigation, and growers often benefit from being able to control vine vigor through minimal and timely irrigations, insufficient water can be detrimental to vines accustomed to irrigation and can cause issues with low vigor, and overexposed fruit that may burn or shrivel.
The other concern about low water availability is for growers who use sprinklers for frost protection. This season may turn out to be a long and challenging frost season, since high pressure systems with clear skies have dominated leaving sunny days with cold, frosty nights. Budbreak is early, meaning this frost season may last longer than usual. Growers in less frost-prone areas will get better sleep in the next few months, and those with wind machines are in a better position than those with sprinklers as long as the inversion layers remain strong and the temperatures do not drop down too low. This may be the year to invest in orchard heaters and/or back-up wind machines if sprinklers have been your primary method of control. It is virtually impossible to even find a wind machine to rent. And get your mowers out, as tall cover crops will impede air flow and cause even greater frost risk!
Another long-term consideration about drought comes to mind when thinking about California’s most recent drought year of 2008 when wildfires burned throughout California. Napa already experienced a fire in the hills late this February when a controlled burn got out of hand on a dry, windy day. Fortunately, it was controlled overnight and there was little property damage and no one was injured.
What is ironic is that although these concerns are all reasonable given the current knowledge, we cannot predict the weather. Even weather forecasters have a hard time doing so, but they are currently forecasting some rain and unsettled weather this week. Significant rain this March and into early April will benefit us by filling the soil profile and reducing the frost risks. Let’s hope it comes now and not later in the spring when it challenges growers with high vigor and increased risk of diseases.
Most of my vineyards have not quite experienced budbreak yet, but judging from the level of bud swell, Chardonnay, Pinot noir, Malbec, Tempranillo and other early blocks and varieties will experience budbreak within the next week or so. This is a little bit early compared to ‘average,’ and significantly earlier than the two prior late years of 2011 and 2010.
At this point, lets remain optimistic that this week's weather events will fill our soil profiles and that overall the relatively dry winter will at best give us less concerns for vine vigor and disease prevention and allow us the flexibility to irrigate as needed and produce winegrapes with better concentration and riper maturity.
This article assumes some level of familiarity with cane and cordon pruning techniques. If you are not familiar with the differences between cane and cordon pruning, it may make sense to review my prior posts on those subjects:
Cordon training/pruning is popular for its simplicity. It takes less time than cane pruning and does not require a very skilled worker; therefore it is less expensive.
However, cane pruning is preferred to cordon pruning because the selection of which cane and the cane length by a skilled vineyard worker can fine tune the balance of each individual vine better than cordon pruning.
Additionally, cane pruning can improve yields. The buds on a cane tend to be more fruitful than the buds of spur positions on a cordon. When cordon pruning, only basal buds of the prior year’s canes are left to grow in the following season, whereas in cane pruning, a longer length of cane is left. Although varietal dependent, these apical buds tend to be more fruitful than basal buds. This is especially true as vines age.
Cane pruning also spreads the following season’s shoots out, requiring less suckering in the spring. Only one shoot grows per bud or position along the cane, whereas two shoots grow from a traditional cordon’s spur position.
Many older cordon-pruned vineyards suffer from serious loss due to dead spur positions and arms from Eutypa or Bot canker.
Between yield loss from Eutypa and lowered yields with older cordon vines, many growers are converting their cordon-trained vineyards to cane pruning. By doing so, it is possible to cut out most of the cankers in the vines.
The best way to do this takes a couple years. In the first year, a sucker from the base of the vine (but above the graft union) is selected and maintained throughout the growing season. During pruning, this sucker is pruned back so that it is as tall as the fruiting wire, and the lower part can be dis-budded allowing only a few top buds to grow the following season to produce 3-4 shoots. The rest of the vine is pruned normally this year.
This method may crowd the fruiting zone near the head of the vine during the second year, but it causes no loss of productivity. The following winter, the sucker will now be a replacement truck with 3 to 4 canes growing out of the top that can be used as canes. The old cordon and the trunk can be removed to a few inches above the new replacement trunk. The replacement trunk can be tied to the vine stake and canes can be selected and tied to the fruiting wire.
Some vines may not push a sucker in the first year, but will do so in the second year. Also, some growers may not have the patience to do this over two years. If vines push a strong sucker in the second year, or year one for the impatient grower, that sucker may be long enough to serve as the trunk and a cane the following season. If not, it can just be used as a trunk, and the following year it will produce canes, causing only a one-year loss of productivity.
As an example, in this photo, after year one, a strong sucker was selected and used as a trunk and a cane, and the old cordon and trunk were removed to just above where the sucker emerges. The vine had lower productivity, but no loss of productivity. When we prune it this year, we will cut the sucker down to the fruiting wire to be a trunk and use this year’s shoot production to select two canes.
If you do not want to wait two years, then the entire vineyard can be converted like this as long as the majority of vines have strong suckers selected in year 1.
Without waiting at all, a cordon can be cut back to one or two spur positions and a cane can be pulled down and tied to the wire from one of these first spur positions. Two positions per cordon should be left if you want two canes from each side for very vigorous vines, or only one position per cordon will be sufficient if two canes will be used. The problem with this is that you may not cut the canker disease out if it has moved into these remaining spur positions near the head of the trunk. Also, older spur positions tend to be long, and you may need to bow the cane to get it to tie back down to the fruiting wire. With a really long spur position, the new cane may be bowed significantly and may bend under the weight of the fruit during the growing season. A new fruiting wire may need to be added near the top of the spur positons.
Here is an example of vigorous Sauvignon Blanc vines that had significant Eutypa and low yields. It needs 4 canes to be balanced, so two spur positions were left on each side of the vines. One cane on each side is bowed and tied down to the fruiting wire. The other cane is tied to the first set of moveable catch wires. If the grower continues with this conversion, they will likely add a new set of two fruiting wires near the top of the spur positions so that all four canes can be tied at the same height and rest along secured fruiting wires in a split canopy system.
These conversions can be expensive, requiring vine surgery and in some cases, additional wires or trellis modifications. If canker diseases are not a major issue, but low yields are, and a desire to cane prune exists, there is the ‘mini-cane’ conversion below. In this instance, a short cane is selected from about every third spur position and tied to the first catch wire. This will not cut out any canker diseases though. This requires no trellis wire and no surgery, although you may want to consider removing the spur positions in between the canes or at least disbud them, or you can remove them during suckering.
In all cases, it still makes sense to seal pruning wounds with a sealant such as B-lock to protect them from canker diseases. This is especially true if you are performing vine surgery and making large cuts. It is also recommended to do this type of surgery late in the winter once most fungal disease spores are already dispersed. And it probably makes sense for new vineyards to be trained for cane pruning so that a time consuming and costly conversion is not needed later.
Email or call me if you want to discuss the best way to make a conversion in your vineyard. All these methods have their pros and cons.
Napa Valley has received less than a third of average rainfall so far this season. After being relieved of a drought pattern in 2010 and 2011, meteorologists are beginning to utter the dreadful ‘d’ word again. Even with a wet spring, there is little chance that we can build up California’s snow pack and replenish the supply needed for 2012.
A little bit of rain is on the way for tonight and tomorrow, but amounts are forecasted to be less than an inch in most areas. At this point, anything helps, but we could use more, and the weather is forecasted to clear shortly after this event. In fact, forecasters are predicting a drier than average February and a near average 90 day precipitation forecast.
The bonus of a drier winter has been that growers have made a lot of progress pruning. There shouldn’t be a race to finish pruning this year before budbreak occurs, even if budbreak appears early as a dry and warm winter may suggest. And weather has been nice for the people doing the pruning! Additionally, weed growth has been kept to a minimum.
Let’s hope that the forecasters are wrong and we get some significant rainfall this month and March. It would not be ideal to have another wet late spring since that makes canopy management more difficult and vines excessively vigorous and poses additional problems controlling diseases such as mildew and weeds.
The one thing that is predictable about farming is that it is unpredictable. We learn to plan ahead as best as we can, and to be flexible and react to what nature delivers.
Protecting Napa’s valuable natural resources has not always come easy. Competing interests and political initiatives throughout Napa’s history have generated controversy and often polarized groups with differing opinions. In this contentious environment, developers and landowners have argued against environmentalists in order to protect their property rights to develop and subdivide land as they wish. Environmentalists themselves have become fractioned between those that believe vineyards are an economical and sustainable way to preserve Napa’s land from urbanization and those that believe that vineyards pose a threat to Napa’s environmental sustainability. The struggle for balance between development, agriculture, and nature’s preservation has created a unique story of passion, politics, and ecology.
In 1968, Napa County began its first political measures to maintain the county’s commitment to agriculture, the vineyard industry, and to sustaining the health of the environment and watershed by enacting the United State’s first Agricultural Preserve. The Agricultural Preserve was initially drafted to protect approximately 26,000 acres of farmland, by creating a minimum lot size within the Preserve of 40 acres. Proponents felt that this would protect the agricultural nature of the county. Opponents argued that the Preserve would unfairly limit the rights of landowners to subdivide the land for home sales or as inheritances and also lower the value of the land. Ultimately, the bill was modified and passed, and the Agricultural Preserve now covers nearly 40,000 acres within Napa County (Carson 2008) although parcel size has been modified over the years depending on the amount of farmable land within the parcel. Furthermore, in 1975, Napa County adopted a land use element to the county’s General Plan that designated land in the Agricultural Preserve as Agriculture, Watershed, and Open Space (AWOS) with a minimum parcel size of 160 acres or Agricultural Resource (AR) with a minimum parcel size of 40 acres and included regulations on maximum building intensity for these designated lands.
In 1990, residents of Napa County were surprised when the San Francisco Bay Regional Water Quality Control Board listed the Napa River and its tributaries as impaired by too much sediment according to the federal Clean Water Act. Although there are many causes for this sedimentation including increased urbanization and municipal dams, vineyard development had increased significantly and hillside development and certain vineyard management techniques were contributing factors. The sediment had negatively impacted the watershed by reducing habitat and biodiversity and threatening fish and other species.
In response, Napa County enacted Conservation Regulations in 1991 to address erosion control and stream setbacks. The intent of the regulations was to protect lands from excessive soil loss and maintain or improve water quality by minimizing soil erosion into the watershed during vineyard planting. The regulations included setbacks from streams and rivers to preserve riparian habitat and protect waterways. The Conservation Regulations also require Erosion Control Plans for agricultural projects involving grading and earthmoving activities on slopes over 5%.
In the years following, Napa County has become a leader in sustainability initiatives, and growers in Napa County farm with some of the strictest regulations and highest standards of agricultural anywhere in the United States. Achieving these standards has come through the hard work and dedication of vineyard managers, landowners, government representatives, and environmentalists. Although controversy and debate have existed throughout the history of Napa County, the results of all of Napa’s stakeholders working together to enrich the environment while maintaining and improving the wine industry has been realized through the success of Napa Valley wines in the global market, and the revitalized health of the Napa River’s watershed.
For more details on this incredible journey, read the chapter I wrote in The Business of Sustainability. http://www.amazon.com/Business-Sustainability-volumes-Policies-Practices/dp/0313384940
An unusually dry winter has caused concern across California. Areas received less than 10% of their average rainfall in December, and virtually no rain has fallen yet in Napa Valley in 2012.
This year’s La Nina season is clearly different from the others, and it is unlikely that we will be able to catch up to an average year even if we have above average spring rainfall. California has not experienced a drought since the years leading up to and including 2009; let’s hope that we don’t have a return to drought conditions.
The upside of this is that we have been experiencing lovely, crisp sunny days and have been able to get a lot of pruning done. Additionally, there has been less of a concern of fungal pathogens, such as the canker diseases Eutypa and Bot canker, that are dispersed via rainfall and can enter the vine through its pruning wounds.
It is still recommended to prune as late in the season as possible when the spore counts for these diseases are lower. If that is not possible, it is recommended to pre-prune cordon trained vines, by removing most of last year’s growth, and leaving 10-12” canes. If an infection occurs, it will be cut out when the final pruning cut is made. Pre-pruning speeds up the final pruning pass, and if a grower is delaying making this pass as long as possible, it may be essential for it to be quick, especially if spring rains are occurring as bud break approaches. Cane pruning is less susceptible to these canker diseases. Regardless, all pruning wounds should be treated to prevent these diseases.
Pruning is the most critical practice in the vineyard for achieving vine balance. Two few buds selected can lead to overly vigorous growing points that remain in a vegetative state and shade and do not properly ripen grapes. Conversely, too many buds can cause a lack of sufficient vigor and the resultant vines will be overcropped and suffer from ripening and concentration issues. Pruning can be quite technical and crews should be trained to adjust their pruning techniques on an individual vine basis.
Weed control is another winter practice; however, the lack of rainfall has led to little ground cover, both desirable cover crops and weeds.
The recent forecasts have storm systems dipping into our area the second half of the month. Let’s hope we get some good storms in! Better now than in the spring!
The wet ground invigorated vines and growers were busy this summer keeping the vegetative growth in check via the practices of suckering, hedging, and leaf and lateral removal. However, after literally getting burned after removing too much canopy in 2010, growers were cautious and conservative in leaf removal this summer.
Many blocks needed little or no irrigation this year except for steep hillside blocks and blocks with well drained shallow soils. A few strategic irrigations, especially post veraison, were sufficient in most cases.
Due to the lighter crop and vigorous vines, not much thinning was required to achieve vine balance, but thinning was advised in heavier set blocks, as well as in late ripening blocks with hopes that a light crop will achieve optimal ripeness in this late year.
Weather was moderate for late summer, allowing for slow and steady ripening. Fortunately, no significant heat waves occurred and therefore no fruit was damaged due to heat events. This year’s harvest was one of the latest harvests on record, with earlier varieties like Sauvignon Blanc and Pinot noir coming in the second half of September.
Significant rainfall from October 3rd through the 6th, followed by a warm drizzly day on the 10th, set up significant challenges for some blocks that had not been harvested already. In anticipation of and in reaction to the rain, growers removed leaves in many blocks to reduce the risk of mold and to allow the sunlight that followed the rainfall to have its most significant impact on maturation of the grapes. The rain delayed an already late Cabernet harvest, and certain blocks of Chardonnay, Merlot, Cabernet and other late varieties, particularly those with poorly draining soils or poor airflow, experienced some issues with mold. Heavy and careful sorting was used to mitigate these issues. Many blocks made it through the rain just fine, and we were blessed with a lovely second half of October allowing the harvest to finish without further issues.
It was a challenging season, and certainly a reminder that