With Don Shor & Lois Richter

Gardening West of the Causeway

Davis climate and region

• River floodplain• ‘Mediterranean’ climate: rainy winter, dry summer.• Mix of soil types, mostly mineral• Annual grasses and oaks• 17- 20” of annual rainfall• 90 degree highs June - September• Delta breeze, coastal influence• Several frosts between Nov. - February.

Hot summers• Average high July - August: 90 degrees• Many pleasant spells in the 80’s. • 10 - 20 days over 100.• 40+ degree temperature swings• Hottest ever: 117F. • Hottest spells usually early - mid July• Very low humidity from May - October• Delta breeze is our natural air conditioner!• Sunset Zone 14, USDA Zone 9.

Cold, wet winters• First frost Thanksgiving, last frost Valentine’s • Some nights in mid-20’s• Lowest ever: 16F (1990 freeze)• Latest frost ever: early April• Significant freezes in 1990, 1998• Coldest spells usually mid - late December• Tule fogs November - January• Valley fog in December - early January

Storms & winter rain

• Typical storms form in Gulf of Alaska, move in through the delta south of us.• ‘Pineapple express’ storms come across the warmer Pacific. Warmer, wetter.• Typical first rain around Hallowe’en• 1/2” - 1” typical per cold front• Heaviest rainfall Dec. - February• Significant rainfall rare after mid-May• Flooding can occur after soil is saturated.

Wind!

• Prevailing winds from southwest are off the ocean, through the delta: help to moderate temperatures in the summer (‘delta breeze’)

• Gusty winds from the north are off the land: dry and hot in summer, dry and cold in winter. Desiccate plants, break tree limbs.

Soils

• Clay to sandy loams are typical.

• Sandier loams close to creeks.• Denser clay loams on north, west.• No true ‘hardpan’, but a ‘plowpan’ in some areas.• Very low natural organic content.• Water penetrates slowly, runs off readily.• Soil naturally retains moisture: water slowly, deeply, infrequently.

Water

• Groundwater: water comes from wells.

• High in dissolved salts: calcium, boron, and others.• High pH: water is alkaline.• Acid-loving plants have special needs. • Other plants may show nutrient deficiencies: iron, zinc.

What can we grow?• summer and winter vegetables, herbs• ‘stone’ fruit trees: apricots, cherries, peaches and nectarines, plums• persimmons, pomegranates, figs• nut trees• cane berries• citrus• many subtropicals• perennial flowers• seasonal (annual) flowers

What plants have special needs?• ‘Acid-loving’ plants require pH correction.• some plants are easy to overwater in heavy soil areas.• many apple varieties perform better with cooler autumns (and codling moth is a nuisance). • some subtropicals are marginal; truly tropical plants must be inside Nov. - March.• some high elevation or coastal plants can’t tolerate the long, hot, dry summer.