Recovery of vineyards after frost and protection against freezing temperatures

Restoring vineyards after winter frosts and spring freezes

After severe winters or late spring frosts, the primary task for an agronomist is to maintain the structure of the vine and protect the future harvest. Before starting work, perform a detailed diagnosis of the plantings. Evaluate the viability of the root system, as well as the condition of the trunk, cordons, one-year shoots, and buds on each plot. The subsequent pruning strategy depends directly on the nature and extent of the tissue damage.

If the perennial wood has not been damaged and only the buds have frozen, adjust the vine load. If more than 30% of the buds have died, calculate the additional load considering the survival of primary and secondary buds. During the summer period, regulate the load using lateral shoots.

If frost has damaged specific cordons with fruit shoots, cut them back to healthy wood. To rebuild the structure of the vine, use sucker shoots, water sprouts, and lateral shoots. If the aerial part has completely frozen, cut the vines back to the “black head” and rapidly form a new canopy from suckers and water sprouts, incorporating lateral shoots.

In regions with a high risk of spring frosts, protect the vines using training systems (e.g., Sylvoz cordon) and two-stage pruning.

1. Perform preliminary long pruning and tie the shoots vertically.
2. Wait for the end of the spring frost period. Due to vertical polarity, only the 2–3 uppermost buds will start growing, while the lower ones will remain in a dormant state and will not be damaged.
3. After the threat of frost has passed, perform the second (final) pruning. The lower buds will begin to grow, and the fruitfulness of the vine will not decrease.

If a spring frost has damaged only the tips (growing points) of the shoots, but the inflorescences have survived, do not prune. However, if shoots with inflorescences are damaged, remove the damaged part of the shoot to induce growth from secondary or lateral buds. This technique is only effective for cultivars capable of initiating reproductive organs on such shoots. In the case of complete bud death on green shoots, use short pruning to awaken dormant buds.

Rehabilitation after hail and proper pruning techniques

Hail requires prompt intervention from the agronomist. The nature of the pruning depends on the developmental stage of the vine and the severity of the wounds. The main principle of rehabilitation is to preserve the maximum leaf surface area. Damaged, withered, or broken cordons should be removed minimally, and the leaf canopy should be restored through the active development of lateral shoots.

In the summer after a hailstorm, it is possible to obtain a harvest from lateral shoots or secondary buds by adjusting the Pruning of fruit-bearing shoots. If the hail occurred during the ripening phase, carefully remove the damaged berries from the clusters and leave the intact ones to ripen (provided the vines have retained their foliage). Due to the imbalance between the roots and the canopy after the hail, vigorous shoot growth from dormant buds will begin. Regulate their density by thinning, leaving only the best canes to form future cordons and fruit-bearing units.

Correct cutting technique accelerates wound healing and protects the vine from infections. Shorten the cane 2–3 cm above the bud with an angled cut sloping away from the bud so that the bleeding sap does not run onto it.

When completely removing shoots or perennial branches, modern technology recommends cutting "to the collar," without leaving stubs. The cut must be perfectly flat and smooth—this ensures rapid wound closure without cracking or tissue decay. To speed up work in industrial vineyards, manual pruning is combined with mechanized pruning.

• Cut height above the bud — 2–3 cm
• Short pruning for frozen buds — to 4–5 buds
• PAV-8 productivity — 200–300 vines per hour

When pruning manually, the blade (the wide part) of the secateurs should always be directed towards the part of the vine being kept, and the anvil (the narrow part) towards the part being removed. Saw off large perennial branches with a pruning saw, and then be sure to clean the cuts with a knife or secateurs.

In vineyards, after pruning and harvesting cuttings for propagation, a vine shoot collector, the LNV–1.5A vineyard vine collector, with a capacity of up to 2 ha/h, is used to collect pruned shoots.