December 11th, 2012« Back to Learn
Good morning and a very happy holiday season to all of you from all of us at Flying Leap Vineyards. We started our vineyard several years ago for one reason – to bring the joy of Arizona wine to our community and promote this wonderful yet little-known winegrowing region. We hope you have enjoyed being a part of our progress, and thank you so much for your interest in our efforts.
We have been busy in all aspects of our operations, and we simply haven’t had time to send out an update for a while. We wanted to blog about some of the more interesting things we’re doing at the moment, and with the temperatures dropping and a chill in the air (last night, it got down to 17 degrees in the Kansas Settlement), there is none more interesting and on our minds this winter than protection of our 2013 crop from the coming late spring frosts. So, we’d like to share with you some insight into what we’re doing to protect our vineyards from the coming frosty Arizona spring.
For two years now we’ve been focusing our efforts on developing our vineyard infrastructure in our Kansas Settlement properties. We’ve shared a lot of this with you– from clearing the land, removing mesquite to soil preparation, varietal selection, irrigation installation and so much more. All of this has been focused on putting in place the hardware in the ground and above to grow our crops – to produce high quality wine grapes in abundance, and to do so efficiently.
The first vineyard blocks are now ready to move into a whole new phase – fruit production. Our goal in the coming growing season is to pull 25 tons of winegrapes from our Block 1 vineyard in the Fall of 2013. With production now being a primary objective, we have to develop a way to protect our vine buds from being wiped out by late spring frosts.
Many people not familiar with the American southwest are amazed that farmers here have to worry about cold, freeze, snow and frost, but indeed we do! Folks, it gets really, really cold in Arizona. There are two general ways to protect your crop from frost – passive & active means. I guess you could also do nothing and hope & pray. Regardless, frost damage of crops is a huge issue in Arizona, and especially so with wine grapes.
Passive Frost Protection
Passive frost protection is subtle, but starts with how we designed the vineyard itself. We aligned our rows downslope, so that the frost-causing cold air mass would move through the field rather than transverse (across) and ‘sieve’ through the vines. We also located our vineyards well upslope to take advantage of the natural movement of cold air (this is a reason the Willcox bench region in particular is so well-suited for growing wine grapes).
Other passive and not so obvious frost protection measures lie in the actual grape varietals we selected for the KS properties. We chose some very late-budding varietals, such as Mourvedre and Graciano, which are protected from frost damage by virtue of being dormant when the damaging conditions arise.
Passive frost protection is great because it’s cheap – you don’t have to do squat. But, passive protection has some serious limits, especially when you get a killer situation called a ‘radiant frost event’. I’m not gonna geek out here and go into the physics of how frost forms, but in this business let me assure you that we study it in extreme depth & detail – frost is a BIG deal to us.
In the simplest way I can explain it, a radiant frost occurs when a sudden drop in temperature due to irradiation of the vines and soil (letting off stored heat) causes the surrounding air to cool very rapidly. The rapidly chilled air settles into the lowest areas in the vineyard causing frost damage. This cold air displaces warm air, which floats above it forming what we call a temperature inversion. The best way to visualize this is as an Oreo cookie. The dark cookie is the vineyard floor, and the white cream filling is the warm air above it. Problem is, the delicate buds on the grapevines are down in the cold air – and when radiant frost forms, the buds freeze and die. No buds – no grapes, and no grapes, no wine.
Active Frost Protection
One well-proven method to actively protect the tender buds from freezing in a radiant frost event is to use a wind machine. These monster sentries are places in vineyards and orchards to put a great big powerful fan way up into the warm air on a tall tower to pull that warm air down into the vineyard floor to displace and break up the cold, settled air mass. A wind machine can raise the temperature at the vineyard floor by as much as 6 degrees during a radiant frost. That seemingly small degree of temperature protection can literally mean saving an entire crop – it is that important.
At our Block 1 field, we are installing a wind machine for this exact purpose. A company called Orchard-Rite makes the unit we are purchasing in Yakima, Washington. It consists of a large fan with a diameter of nearly 20 feet. It sits up 50 feet on top of tall tower and runs by way of a Ford propane engine – a V10 with a rated output of 170 horsepower. The unit is rated for and designed to provide 3-6 degrees of temperature protection for an 8-10 acre area of the vineyard. The exact amount of temperature protection depends on many things, such as degree of frost/freeze and the characteristics of the temperature inversion, surface winds and terrain slope, to name a few. Bottom line – they work.
Installation of a Wind Machine
Once we made the decision to purchase and install a unit, we set to work designing the installation details. One of the most important issues to solve was where to put it. To determine this, we studied satellite pictures of our property and worked with what’s called DTED (“Digital Terrain Elevation Data”). In doing this, we could visually see the elevation profile of our entire area, which gave us insight into how the settled cold air mass would move under most radiant frost events. For example, because our field slopes down at about 2-degrees, and because the terrain steepens somewhat to the west, we deduced the fan’s protection would be more of an egg shape than a perfect circle. Using our maps, we also figured out we need two fans to cover the entire field (Blocks 1 & 2). However, we are only going to install a single unit in 2013, and the next unit in 2014.
With the precise location of the machine now known, we surveyed the measurements and realized that in order to put in the wind machine, we were going to have to physically create a small lane into the vines so that we could get to it. The spot required us to make an 85-foot transverse, lateral cut (‘road’) into the heart of our Block 1 vineyard – meaning we had to literally pull vines out, cut a lane right through 8 rows of trellis and as a result, move irrigation lines and install a whole new underground irrigation branch to accommodate the new arrangement. We would also have to install new steel end posts – so, in all we were looking at a lot MORE WORK.
- – The first thing we did was carefully mark the vines and stakes we wanted to remove by placing ribbons on them. See the attached photo called “Vines & Stakes Marked for Removal.JPG”.
- – Second, we removed the vines and stakes to roughly clear out the new lane so we could get our heavy equipment in there. See the attached photo called “Vines & Stakes Removed – Lane Cleared.JPG”.
- – Next, we surveyed out the lane dimensions (length & width) and marked the location of the new trellis end posts. See the attached photo called “New Location for End Posts Surveyed.JPG”.
- – Next, we used our tractor and PTO-driven trenching tool to dig about 180-feet of new trench for the irrigation branch and extension. See the attached photo called “Cutting New Irrigation Trench.JPG”.
- – Next, good ole Jose came over to help me drive in the steel end posts. See the attached photo called “Installing Endposts.JPG”. The end posts are 10-feet in length and weigh 150-lbs each. They come from oil well drill shafts, are very strong and extremely hard to pound down. We drive them 4-feet deep using a pneumatically driven post pounder. The pounder weighs about 180-lbs, so we lift it up using the tractor forks, as shown in the picture. Depending on the hardness of the soil and the rocks below, it can take up to an hour to drive down a single post. So far, we’ve driven down the end posts – which was a sunrise to sunset job this past weekend.
- – Our next tasks are to re-string the trellis and complete the irrigation installation.
- – Last, we have to dig a hole 8.5’ x 8.5’ x 30” deep to accommodate the concrete footer for the wind machine.
- We’ll send pictures of the rest of the installation after the Christmas and New Year’s holidays.
*** That’s a Rap ***
Until next time, we thank you for your interest in Flying Leap Vineyards, and we look forward to sharing our 2011 vintage, which is being released in January. We also have some very big news at the vineyard and we’re dying to share it with you, but we’re keeping that a secret until January!