So since 2008 we've plowed between the rows to eliminate weeds and provide more soil moisture for the vines. The soil is both sandy and low in nutrients so it holds little moisture and provides little nutrients to the vines. Yet the vines grow, albiet slower than what one may expect and takes 6-7 years to reach full maturity.
Now that the vines are fully established we are seeding clover in ever second row. We started this last year and this spring it is coming up great and so now we are continuing with planting the clover in the rest of the vineyard. The clover will help to build the soil over the years yet it will consume alot of soil moisture. However now that the vines are mature with full and deep root systems they are less prone to soil water deficiency. In fact, over the past few years the vast majority of or vineyard has really not received any irrigation.
There are a few things at play here here that help us eliminate the need to irrigate.
- Once the vines are mature, about 6 years old, they've developed a significant and deep root system that supplies their needs.
- Second, while we usually dont get any rain from early July to the end of August, our season is short, about 150 days/5 months long, so we dont have extremely long and extended periods without rain. In relation to this the snow usually doesn't finish melting until early April and its only 3-4 weeks later the vines are budding out. In contrast, varieties that take 180 days/6 months to ripen would suffer if in that extra month of drough was not replenished with irrigation or rainfall.
- Third, we leave extra spacing between the rows, while limiting production, so this give a larger area for each vine to draw water from.
- It is not uncommon to get cool summer evenings that result in precipitation of significant dew on the leaves and even the soil that help replenish some moisture. We blogged about that previously see link Moisture From Air
- We usually get sporadic rains in May and June and the soil is still flush with moisture until mid July and then it starts to deplete. There is usually enough weter in the soil and from rain to fill out the grapes and then by the end of August, early September its pretty dry but in time for reducing soil moisture content heading into harvest.
The clover will consume some of that valuable moisture but now that the vines are mature they can handle these conditions without irrigation and the clover will serve well to build the soil over time and provides a great habitat for bees.