BigH
Senior Member
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- Apr 27, 2014
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One thing I haven't wrapped my head around: grass and weeds only put down roots a few inches,... How does 2-3" of grass actually starve the grapevine when it is pulling from a different and far more massive layer of the earth?
For immobile nutrients like phosphorous and zinc, the short grass roots probably don't compete with grape vines. Mobile nutrients are a different matter. One key form of nitrogen (NO3) is highly mobile and moves with water throughout the soil. I would expect grass and grape vines to compete heavily for it, regardless of root depth.
Also, don't forget about water itself. Any water taken up by grass will never reach roots of the vine. Double whammy because that water would have brought some NO3 nitrates along with it.
My soil is pretty high in organic matter and very well drained. I actually want grass stealing some of those nutrients to suppress the vigor of my mature vines.
H