Hi, Allen -
Just saw your post and called our Chief Analyst for his opinion. Grapevines need to have stored energy in the form of sugars and carbohydrates when they go dormant in the Winter. These provide the energy for blooming and fruiting the next season. Grapes are what we consider a crop with special nutritional needs - Phosphorus is particularly important. You said something very telling - that the vine appeared healthy with lots of foliage. This suggests that it may have too much Nitrogen.
Here are links to our grape papers that you may find of some interest - even though they are written for the commercial grower:http://www.texasplantandsoillab.com/PDFs/grapes/GRAPE-GUIDE.pdfhttp://www.texasplantandsoillab.com/PDFs/grapes/grapes-vineyard-nutrition-notes.pdfhttp://www.texasplantandsoillab.com/PDFs/grapes/GRAPE-PETIOLE-TEST-3P.pdf
- See Page 3.
Here is the link to the grape page on our website: http://www.texasplantandsoillab.com/grape-testing.asp
We take grapes very seiously and we're going to two grape grower events in West Texas this month. We're a member of ISEV and a very active member in TWGGA...
Lemme know if we can answer any questions.