Hail Protection Netting in vineyards is a specialized protection system and an essential tool to safeguard production.
Scientists have been warning us for some time now about the consequences of climate change. Rising ocean temperature, sea surface temperature, and land temperature results in more severe weather, including later spring frosts and more frequent and severe hailstorms.
A severe hailstorm can cause devastating damage in a vineyard. In one half of an hour a hailstorm can destroy a year of work and investment.
Not only can fruit be knocked off or damaged but so can flowers and leaves, and shoots and trunks can be cracked. The immediate damage is further exasperated by poorly performing vines, resulting in losses in both quality and quantity at harvest. Some grapevines may not survive.
There are three methods for dealing with the threat of hail damage: hail canons, cloud seeding, and netting.
There is not very much sound science behind hail canons or evidence that they work (the loud boom supposedly disrupts the hail-forming process in the cloud), but there is good science behind cloud seeding.
Cloud seeding does not prevent hail from forming, but chemically induces many more hailstones to form so that individual stones are much smaller and hopefully have melted or are insignificant in size by the time they fall on earth.
Cloud seeding does not provide complete protection and seems to be more successful in some regions than in others.
Whereas hail canons and cloud seeding attempt to prevent hail, anti-hail netting (also known simply as hail protection netting or hail guard mesh) provides a physical barrier to protect a crop from hail.
When properly installed, hail protection netting is the surest protection of the three methods against hail and is indispensable in areas with a high incidence of hailstorms.
Cost Effectiveness of Hail Protection Netting
A crop protected by anti-hail netting assures consistency in marketable product, both in quality and in quantity. Hail protection netting is a proactive defense to safeguard the crop.
However, it is a considerable investment and the losses that it prevents need to justify the cost. In regions of severe, frequent hail, netting is an obvious choice; whereas, in regions with almost no hail, it may not be worth the investment.
Hail protection netting is a proactive defense to safeguard the crop. However, it is a considerable investment and the losses that it prevents need to justify the cost. In regions of severe, frequent hail, netting is an obvious choice; whereas, in regions with almost no hail, it may not be worth the investment.
Careful calculation needs to be done first to determine the potential for return on the investment. Two recommendations to follow are 1) start small and 2) do it right.
Do a small area if in doubt about the potential returns. Evaluate the results and then decide whether or not to install more hail guard mesh. Many who start small do end up netting the whole vineyard. Whatever amount you do, do it right.
Do not skimp on costs which will save you money the first year but cost you more in the long run than what doing it right would have or will save you money initially but, because of low-quality netting and/or an inadequate support structure, ends up leaving the grapevines with inadequate protection.
Hail protection netting may not only prevent losses from hail but also losses from birds eating and damaging grapes. If pest birds are a problem, take the problem species into consideration when choosing a net. One net may be able to provide both bird and hail protection.
¿Why implement an anti-hail system?
Preventing bird losses would be additional justification for investing in anti-hail netting. The netting will also reduce sunburn, wind damage, and frost damage. Conversely, in regions with inadequate sunlight, further reducing the amount of light (even though just slightly) could be detrimental.
Hail protection netting is an asset and as such its purchase price is not an expense in the year of purchase.
A support structure for hail protection netting in vineyards
A support structure is not necessary in all cases. An option is to place the netting directly on the grapevines, draping it over both sides of each row. This can be done by hand in smaller vineyards; and, for larger vineyards, there are machinery and devices available to facilitate the installation of the netting at the beginning of the season and its retrieval and the end of the season.
An alternative is rolling up the sides and leaving it over the top of the row. When starting small, the drape netting method is an option to consider. Structure becomes more important in the case of high density vineyards.
The basic elements of a support structure for hail guard mesh are:
- Cables and ropes
- Shields for the poles
ANCHORS should be placed all around the perimeter and should be capable of guaranteeing the stability of the structure. In addition to being able to withstand the forces of strong wind, they also need to be able to withstand the forces of the weight of hail on the netting. They have to consider a correct distance to place them.
POLES/POSTS. The type of post best suited for supporting hail protection netting is a concrete post.
CABLES AND ROPES. When we have an orchard and we want to implement a protection system, it is important to place the cables to avoid damage to the mesh.
SHIELDS FOR THE POLES. A post shield not only serves for protecting and preserving the hail guard mesh, but also for securely fastening the top part of the post to the crosswise cables which is what keeps the post plumb.
GRANITA® Anti-Hail Protection
GRANITA® is the hail protection netting made by HORTOMALLAS. It is made of high-quality polyethylene and It is available in various sizes.
When there is a chance of snow, the netting should be rolled up onto the tops of the posts and left in a roll. This is an annual chore but is indispensable for the protection of the structure and of the crop.
Choosing to install hail protection netting, is the surest way of safeguarding a crop from hailstorm damage. There is a netting and installation method for practically any need or situation.