Time your planting carefully. Cucumbers can be fussy. They grow and fruit best in full sun at temperatures from 55° to 85°F, with optimal growing temperature between 65° and 75°F. They tend to be sensitive and stressed at temperatures above about 85°F and below about 50°F. In Southern California Coastal areas, plant pre-germinated cucumber seeds or seed directly outdoors beginning April or May until July or August when temperatures are within the cucumber comfort zone. Use heat-tolerant varieties and varieties that tolerate temperature extremes.
Don’t plant into new or uncultivated soil. If you’ve just started a garden or haven’t grown in a bare area for a few years, try cucumbers in a raised bed or large containers. Choose an area with plenty of southern and/or western sun exposure. Construct raised beds directly on compacted or infertile soils, with a barrier of half-inch hardware cloth at ground level to keep out gophers. See GardenZeus Tips for Container Vegetable Gardening for recommended soil mix and other tips.
Space plants widely to allow air circulation and avoid wetting leaves. Leaf mildews are a major problem for cucurbits in Southern California coastal and coastal-influence areas. If you have the space, plant cucumbers widely and avoid grouping with any other plants. Water at ground level with drip irrigation or by hand rather than using sprinklers.