Rotation is used to prevent the build up of crop related soil pathogens and the depletion of specific soil nutrients. Venting is necessary for temperature control inside the tunnel and to allow for pollination in certain crops. The color and clarity of the mulch dictate how it will affect soil temperatures. Ninety percent of all commercial vegetable production in San Diego County is under drip irrigation. The majority of fertilizer applications are made through drip irrigation systems.
Most vegetable crops receive weekly liquid applications injected during growth and harvest periods.
Preplant applications of dry materials are often shanked in before transplanting where slopes permit. Formulations can vary dramatically depending on dealer and grower experiences and needs. Amounts of fertilizers recommended for applications are based on yield responses in research, soil tests, and accurate farm records. The addition of organic matter also reduces problems from soil borne diseases. Preventative practices include soil fumigation, appropriate pesticide applications, and planting pest and disease resistant varieties.