Upon completion of this chapter, you should be able to
• explain the need for a crop production schedule.
• explain how and why greenhouse root media vary.
• describe four methods of pasteurizing growing media.
• list three reasons for frequent testing of greenhouse soil.
• list and describe the containers used in greenhouse production.
• list the methods of reproduction used for greenhouse crops.
• label crops on a greenhouse bench.
• describe methods of spacing, watering, and fertilizing greenhouse crops.
• describe techniques of integrated pest management in greenhouses.
• plan production schedules for a representative sampling of greenhouse crops.
CROP PRODUCTION SCHEDULING
The production of greenhouse crops can be compared to the manufacture of nonplant items in one way: scheduling its important. No one buys a poinsettia on December twenty-sixth or an Easter lily on the Monday after Easter. Retail florists need large quantities of red roses for Valentine’s Day, and they sell more mums during the autumn than the spring. In northern states, bedding plants are of interest to consumers for about a six-week period in the spring, and after that they can barely be given away. Unlike other manufacturers, who can store excess inventories, greenhouse growers lose their perishable products and the money invested in them if they don’t sell. Timing is everything in the 470 flower production business.
To serve the market when consumer demand is greatest, and minimize losses due to overproduction or underproduction, greenhouse growers plant, care for, and harvest their crops in accordance with production schedules. In theory, plant production schedules are logical and not difficult to follow. A particular crop can be expected to require a certain number of weeks at a given temperature to go from seed or cutting to harvest. By counting backward from the desired harvest date, the date of planting can be determined. By keeping accurate yearly records, a grower can determine whether to increase or decrease the number of plants produced. Dates of pinching, fertilizing, shading, application of growth retardants, or repotting can be determined from previous years’ data or provided by seed or cutting suppliers.
Theory meets reality, though, when unexpected warm weather sends greenhouse temperatures soaring above those specified in the crop’s production schedule, and crop development advances by a week in only a day or two. Equally troublesome is an extended period of overcast skies, an outbreak of disease, a malfunctioning heating system, or a disrupted photoperiod at a critical stage of plant development. That is when growers must apply their education and past experience to compensate for the unexpected and get the crop back on schedule.
Complete crop records are essential for effective production scheduling. In addition, growers must stay attuned to the economic forecast to anticipate changes in consumer buying. If last year was a record year for sales but the current year’s forecasts are for restrained consumer spending, the crop should be reduced. On the other hand, when a downward trend in the economy is followed by a steady increase, more plants can be grown for sale.