I'm putting in a new vineyard with 9 rows, spaced 7 feet apart. The rows are 3 feet wide and tilled, while the lanes between the rows are 4 feet wide and still intact as typical cool-season lawn (never tilled).
Because I'm on a slope and concerned about erosion, I intend to keep these lanes in grass cover. But should I consider rototilling the between-row lanes now and immediately reseeding with a grass of my choice, or leave them be? My thoughts are primarily about soil compaction. While the grape vines can easily spread their roots laterally up and down the loosened-up soil of the row itself, they might have a harder time making much use of the soil under the grassy lanes. Not only is it an old lawn but I've gone over it several times with a tractor while drilling post holes and such. I plan to rototill the rows once more just before planting to undo some of the compaction I caused the rows themselves, and am wondering if I should go ahead while I have it rented and do the lanes between the rows at the same time, to give my vines maximum ability to extend their roots in all directions. I will not be entering the vineyard again with a tractor, so future compaction will be minimal.
The downside to tilling the lanes, other than the fact that I already have a great cover that I'd be destroying, is that I'll probably have to irrigate new seed to get the replacement grass to take, and I'm thinking it's not a great idea to get the newly planted grape vines wet twice a day from sprinklers.
Also, my soil is naturally very sandy (in fact almost pure sand at the subsoil layer a few feet down) so maybe my concern about compaction is overblown? Is in-row tilling enough preparation?