Bud break on grapes
I want to share with you a secret many grape growers overlook – and it is the effect bud break has on your grape vine.
What is bud break?
Bud break is when the buds on spurs and canes you pruned during winter (or early spring), breaks open and reveals the new growing point of the shoot that will develop from the bud. Depending on the variety, bud break starts about 2 – 3 weeks before the first growing point of shoots are visible.
Why is a strong, even bud break important?
During winter or early spring we prune our grape vines to form the structure of the vine. Another, even more important, reason we prune is to reduce the amount of buds on each grape vine for a smaller, higher quality grape crop. There are many theories on how many buds to keep per vine, but as a rule of thumb you can use the following method.
To determine the number of buds to leave, use the “30 plus 10” formula.
For the first pound of canes removed, leave 30 buds. For each additional pound, leave an additional 10 buds. For most the training systems, the maximum number of retained buds on a grapevine should be less than 60. As you can imagine, having buds that don’t sprout will reduce your crop size even more and can result in a too small crop, making it an uneconomical grape harvest.
The evenness of your harvest will be determined by the evenness of bud break. If you are a commercial grape grower, you want all your grapes in one vineyard, to be ready for harvest at the same time. This will reduce the amount of time spend in collecting the crop because you don’t have to visit the vineyard three or four times to pick all the fruit.
A strong bud break will not only increase ensure a decent crop size, but also make pruning next year much easier. Some grape varieties that is cane pruned, like Thompson, Crimson for example, tends to sprout more evenly and stronger at the last buds on the cane. The biggest problem grape growers have, when this happens, is that they will not find enough pruning wood next year, to retain the structure and amount of buds for a decent crop size.
Look at the picture from one of the My-Grape-Vine customers. This is a classical example of a grape vine sprouting strongly on the tips of the canes and the basal and first buds have a poor sprout percentage.
How to improve an even, strong bud break.
First of all, I want to share with you a theory I have. If you don’t have to cane prune – don’t cane prune. The only reason why you should can prune is when you grow a veriaty that is unfruitful – period! When you spur prune, you will have a much higher bud break %.
So, choosing your pruning method carefully – this will ensure a decent, sustainable crop, year after year AND prune the correct way.
There are lots of so called pruning secrets available on the Internet, but my pruning system I teach in the Complete Grape Growers Guide, has proven itself over the past decade to be the best and most effective way to prune.
The second theory I have is: Proper sunlight penetration.
A grape vine that is too compact (condensed) will overshadow the shoots and and buds during the growing season and as we all know by now, a grape vine needs sunlight to “ripen” the buds on the shoots. In other words; having a well ventilated, not too compact grape vine will improve the bud break percentage.
Now you may ask yourself the following question. “I have a variety that needs to be cane pruned, and is not too compact, BUT I still get a poor bud break percentage – what do I do?”
I have another trick up my sleeve – luckily!
And it is called: “Hydrogen cyanamide (Dormex)” – please note, it is not cyanide, but cyanamide
Applying Dormex to the grape vine’s buds, one month before bud break will significantly improve the bud break percentage and will also make bud break more even.
The concentrate of which it is applied is 3-5 liters (101 – 169 fluid ounces) per 100 liter (26.4 gallons) water for table grapes and 2 – 3 liter (67 – 101 fluid ounces) /100l water for wine grapes. Be sure to read the product label before applying Dormex.
Dormex irritates the skin, so wear proper gloves when you apply it.
If you live in an area where late frost is a problem, I would advise you to be careful. Why? Dormex will not only improve bud break, but it will advance bud break as well. Some grape growers claims to have advanced their sprouting date by up to 3 weeks. My personal experience tells me that id advance bud break by +- one week. So be careful not to advance the sprouting date of your grape vine by so much, that the danger of cold damage will become a bigger concern.
I hope you have enjoyed this blog, and I hope you understand now why an even and strong bud break is so important. You grape growing success depends on this!
For more proven theories, tricks and grape growing tips, you can get yourself the Complete Grape Growers Guide and grow your grape vine like a PRO!
The Grape Guy
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