Climate and Soils

Chapter 4

Climate

Temperature Rainfall Fog Humidity Duration of sunshine

Heat summation

The sum of the mean monthly temperature above 500F.

**base line of 500F because shoot growth nearly stops below this temperature.

April 1 to October 31

Climatic Regions

I = less than 2,500 degree-days II = 2,501 – 3,000 degree-days III = 3,001 – 3,500 degree-days IV = 3,501 – 4,000 degree-days V = 4,001 and more degree-days

Region I

Restricted areas of fertile soil. Hillside slopes & valley areas at best. Recommended for early maturing light

bearing varieties. Can not handle heaving bearing varieties

Region II

In California this region produces the most premium-quality and good standard white and red table wines.

Lower yields of standard wines thus you must grow the higher quality varieties.

Irrigate due to low rainfall.

Region III Level land or slightly sloping and fertile by the

most part. Excellent red wines of later maturing premium

quality varieties are the rule. White wines of fine quality in limited areas. Excellent natural sweet wine & good white & red

wine on the more fertile soil areas. The best port varieties of moderate production

will produce excellent port-type wines. Irrigation due to low rainfall.

Region IV

Fertile soils with most vineyards being irrigated to produce heavy crops.

White and red wines are satisfactory if produced from the high acid varieties.

Natural sweet wines are possible.

Region V

Most uniformly fertile soil in California.

Standard red & white table wines of varying qualities can be made from the high acid varieties.

Irrigation due to low rainfall.

Soil

Pg 73 The quality of table wines is most closely

related to grape variety, followed by climatic region, and least of all, by the soil.

Soil type influenced the level of certain constituents of the grapes and wines, but had no significant effect on wine quality.

Soil

Grapes grow on almost any type of soil.

Grapevines are a desert plant.