Sunday, August 7, 2016

Grape Vines Love Poor Soil - Not Really?

So one of the first things we did years ago when we started the experimental vineyard was to test the soil.  So we took several soil samples from various locations in the vineyard and from various depths surface, 6" and 18".  Generally speaking the soil came back as being devoid of virtually any organic matter or nutrients but the ph was ok in the 6.5 range and most trace elements existed in sufficient quantities.

Well I've read in so many books that grapes like poor soil but I think thats a guideline (like the pirates code) because what is poor soil? What makes a soil good or not good - it  is a pretty general assertion. So with the numbers we got back from the soil test we new we did not have "good soil" in fact if there was an arbitrary spectrum of soil between good and poor soil we would be the poster child of poor soil fore sure. The only thing that would have made it worse was a lower ph.  But our ph was between 6.5 and right in line with what one needs to grow grapes. Anyways as we had read in virtually every publication that grapes love poor soil we didnt bother to do any amendments (didnt add fertilizer, manure etc.) to the soil for the first 5 years or so.

Well we didnt get much growth or production from most of the varieties.  What is remarkable though is that the Leon Millot and the Ravat 34 (in particular) actually did amazingly well in those conditions AND without irrigation I must add.  Other varieties like Seigerrebe and Pinot Noir hardly grew at all and didnt put out a grape until just recently - they looked like some stunted sub-arctic tree. So as I mentioned before its a pretty general assertion to say grapes like poor soils - its like a bad practical joke someone decided to play on anyone who hasn't grown grapes before.

To the contrary, Id say for the most part grapes don't like poor soils, the ones we grow anyways.  Like most crops they do need water and they do need nutients so make sure your vines get both. I grew our vines in quite poor soil for a few years thinking that this was what they would do well with but only a few liked those conditions.  We added water and that helped a bit but not that much. As soon as we added a bit of water and nutrients virtually all varieties improved dramatically.  With 5-6 year old vines we went from producing approximately 0.33-0.5 lb grapes per linear trellis foot to producing 1-1.5 lbs per trellis foot (up to 2lb/foot for some varieties).

Perhaps the best (LOL) part about all of this is that we started the test vineyard on the piece of land that was easiest to break up.  It had no trees but a few small poplars and pines.  The rest of the area around this part was heavily treed and would take tremendous effort to clear and prepare for planting so this area being mostly cleared was chosen.  Looking back I have to wonder why there was nothing growing there and now I know it was because the top soil there had been stripped away due to the logging operation that went on decades earlier - poor soil at its best. If there was no trees growing there I should have known that the grapes wouldn't do any better - live and learn and pass the message on. Make sure your grapes get some nutrients and water right from the start

Good news is now that we've cleared the rest of the land we see that the soil elsewhere is quite good, with lots of nutrients and organic matter.  The new grapes planted in these areas are thriving.