By early September these Marquette vines had filled out and were hedged once. However there were no grapes
VINE RECOVERY FROM FROST DAMAGE
The morning of June 5, 2018. There were no green vines anywhere in the vineyard
By Mid July some growth was observed
- Johnston Vineyards lost 95% of the 2018 grape crop due to the frost the morning of June 4, 2018. It is now being referred to as a “freeze” not a “frost”. The temperature dropped to about -4 degrees C. There was not a green leaf in the entire 32 acres of grape vines. Only a few buds remained viable in the immediate aftermath and these were found on the underside of the fruiting canes (protected from the frost by the overlying fruiting cane). These shoots tended to break off if trained in a vertical position. The critical shoots came from the central region of the plant so that new fruiting canes could be laid down next spring. About 80% of older (3-4 year old) plants started developing these shoots within a month of the frost but few grape clusters formed. These central shoots grew at a variable rate making it necessary to repeatedly go through the vineyard tying up shoots to the catch wires instead of the usual method of raising the catch wires and lifting up all the shoots at the same time. Within 2 1/2 months the 3 and 4 year old Marquette, Riesling and Chardonnay grew tall enough to be hedged.
HYBRIDS VS VINIFERA AFTER THE FROST
Petite Pearl clusters ripened unevenly
Reisling buds leafing out in the critical central area of the vine
Crown gall in the Chardonnay
- The cold hardy hybrids vines such as Vidal, Marquette, Seyval and Petite Pearl (4 years old) developed numerous suckers from the base of the trunk. The overall approach to the recovery process from the frost was to support any leaf development regardless of location to help feed the plant. Suckers were tied up and allowed to grow naturally. Some will be used as fruiting canes next year. The rest will be cut out in the winter. In retrospect, once it became evident that the fruiting arms would not yield fruit, the old fruiting arms probably should have been cut out to promote growth from the center of the plant. Only Petite Pearl and Vidal produced a crop of grapes from the central shoots large enough to justify harvesting. About 1.5 tons (2 acres each) is anticipated from each variety if they have time to ripen. Crown gall occurred extensively in the 4 year old vinifera and 1 year old Pinot Noir. This became more evident by late summer and may have been a consequence of the frost. Crown Gall in the older plants has also been attributed to a malfunctioning grape hoe and over-cropping in the third year.
ONE YEAR OLD VINES PLANTED IN 2017
Geisenheim-318 bud starting out at the base of the frost damaged trunk
Chardonnay planted in 2017 recovered from the frost damage with growth on the trunk and from the base
Geisenheim-318 (own root) planted in 2017 was the last variety to recover from the frost
Petite Milo planted in 2017 recovered from frost damage with multiple suckers from the base
- Normally the one year old plants would be large enough to tie down fruiting canes in the spring of 2019. The Petite Milo (grafed onto 3309) budded out very early and suffered extensive damage in the frost. Buds began appearing at the base of the vines within a month of the frost with 5-8 shoots developing. Once they reached 2-3 feet the strongest 2-3 shoots were tied up and the rest cut off. By the end of August, some reached about 3 feet in vertical height, which will be tied down as fruiting canes in the spring. About 30% of all (hybrid + vinifera) one year old vines (more Pinot Noir than chardonnay) were killed by the frost and will need to be replanted. The chardonnay made the best recovery with buds emerging from the base and last year’s trunk. It will be possible to tie some down next spring (it should be noted that vines planted in 2016 not exposed to a frost in 2017 were nearly all large enough to be tied down in 2018). Thus, close to a year of production was lost. All Geisenheim-318 shoots from 2017 died back to the ground. Most plants grew back from 1-2 suckers at the base of the trunk. Recovery was slow and it wasn’t until late spring when several presumed dead plants were dug out that the new shoots were noted on their way to the surface. The depth of the buds may have been related to the fact that the Geisenheim-318 was not grafted. Quite a few are tall enough to be tied down next spring.
CABERNET FOCH
Caberneet Foch of all ages were killed by the frost
Extensive shoots emerged from the base of the frost injured Cabernet Foch
- This variety again demonstrated why it shouldn’t be planted in Nova Scotia, despite making the best hybrid grape red wine. Most died back to the ground and about 50% of the vines died and will require replacement. The ones that recovered developed a large mass of suckers, but due to the floppy behavior of the shoots they needed to be individually tied up. They might do better with multiple fruiting canes trained up in a fan shape or on the top wire.
CROWN GALL AND VINIFERA VINES
- Crown gall is extensive in the 4 year old Riesling and Chardonnay. It was fairly common in the same plants last year and may have been due to the use of grow tubes (impeded hardening off in the fall), nutritional deficiencies like low potassium, over cropping and a faulty grape hoe that injured the vines. The acceleration in damage this summer can be attributed to the June frost. The vines were severely stressed and crown gall developed at the base of the trunk. Most vines are still green and healthy appearing but will likely die out next year and require replacement. Crown gall also occurred in about 30% of the one year old Pinot Noir and will need to be replaced next year. The potassium deficiency in the soil was partially corrected last year. My personal observation is that vinifera vines planted on land that has been farmed continuously over the years do better than vines planted on raw land left to fallow for years (like that found at Johnston Vineyards). Regular cultivation of the land and replacement of nutrients may gradually contribute to improved resistance to crown gall in the relatively tender vinifera vines. I also have observed that vinifera vines growing at the bottom of a slope gradually decline and die out. This may be due to recurrent colder temperatures and perhaps water drainage issues in these areas. Hybrid vines are not nearly as fussy.
GROW TUBES AND OVER CROPPING
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- Tall grow tubes (36 inch blue) probably accelerate growth of hybrid vines and increase yield in the third year with little ill effect in subsequent years. The more tender vinifera vines probably grow too quickly without corresponding adequate root development which stress the plant and leads to an increase in crown gall. Aggravating factors would be nutritional deficiencies in fallow land and over cropping. We are no longer using long grow tubes on vinifera vines. Short 15 inch tubes are used to mark the new vines and to protect them from the grape hoe. If we were a conventional farm (not organic) they would also protect from herbicides.
- Over cropping is detrimental to vinifera vines (and to a much lesser extent, hybrid vines), especially in their early years before roots are well established. Roots likely develop more quickly in healthy soil that has been continuously farmed. What constitutes over cropping in vinifera vines? Probably more that 1 metric ton/acres in the third year and 2-3 tons in subsequent years, depending on the overall health of the soil.
SUMMARY
1. Extensive vine damage was incurred by the frost (freeze) of June 4, 2018 at Johnston Vineyards in Falmouth, Nova Scotia.
2. Of the 12 varieties growing at Johnston Vineyards only Petite Pearl and Vidal produced a crop after suffering extensive frost damage.
3. About 30% of all vines planted in 2017 died in the frost.
4. About 15% of 3 and 4 year old vinifera vines died in the frost. Very few older hybrid vines died.
5. The frost accelerated the occurrence of crown gall in the vinifera vines.
6. Structural recovery of vines will be a 2 year process due to frost damage to trunks of hybrid and vinifera vines.
