Chapter 20

1. Chapter 20 Greenhouse Production Techniques

2. The production of greenhouse crops can be compare to the manufacture of non-plant items in one way: scheduling is important.

3. To grow and sell when the season and market are best is an example of why timing is important in greenhouse production. • Timing is everything in the flower production business. • To determine whether or not to increase or decrease the number of plants produced from year to year a grower can look at a record of last year’s sales.

4. Four purposes of root media: • Provide nutrients • Retain water • Allow aeration • Anchor the plant

5. Drainage is essential when field soils are used in greenhouse crop production. • Three reasons soil pasteurization may be needed: • Weed seeds • Pathogens • insects

6. Pasteurization – heating soil for 30 minutes at 180 degrees F to kill undesirable things in the soil. • Four methods of pasteurizing growing media: • Surface steaming • Buried pipes • Closed container steaming • Chemical fumigants • Pasteurization only kills harmful things in the soil while sterilization kills every thing.

7. Three reasons growers need soil test: • Check pH • Check for nutrient deficiencies • Measure soluble salt content • Two factor to consider when selecting containers: • Crop • Time of year

8. Containers in greenhouse production: • Pots • Clay containers • Plastic containers • Peat pots • Molded plastic • Hanging baskets • Flats

9. Reproduction methods: • Seed – bedding plants and geraniums • Runners – spider plants • Bulbs – tulips, other flowering perennials • Layering – fig and rubber plants • Cuttings – geraniums, and many foliage plants • Grafting – some azaleas • Budding – roses • Division of the crown – foliage plants • Tissue and organ culturing – orchids, bromeliad, carnation, and chrysanthemums

10. Of the numerous methods of reproduction used by greenhouse growers, seeds and cuttings are most common.

11. The spacing of a crop is very important. Wide spacing is costly due to space, material, and labor issues. However, it helps plants to grow fuller and thicker, allowing them to sell better. • Fixed spacing – no movement of pots after planting. • Expanding spacing – crops started in small pots with close spacing, then container size and spaces can be increased as crop matures.

13. Four conditions from crowded spacing: • Reduce photosynthesis • Increase possibility of disease • Reduce air circulation • Shaded or overly most foliage • Labeling – identifying the plants on the bench.

14. Watering done correctly become irrigation, the maintenance of proper balance of both moisture and air in the soil of crops. • Too much water leaves too little airspace, and the root system may rot.

15. Too little water can also cause shallow root development, soluble salt buildup, and reduced plant and blossom size. • Nature can be blamed for a lot that goes wrong in a greenhouse, but not a water excess or deficiency. • The first and most difficult thing a new greenhouse worker mist be taught is how to water properly.

16. Semiautomatic watering methods: • Spray systems – deliver water through nozzles spaced at intervals. • Trickle systems – deliver water through holes in plastic tubes. • Ooze tubes – plastic tubes rolled between plants; water seeps through small holes.

17. Water loops – used for irrigating container plants; use small rings of plastic placed in containers. • Capillary mat – a mat of fibrous material that is placed under plants; it is periodically flooded with nutrients which the plants will absorb. • Ebb and flood irrigation – water floods a bench and then recedes into a tank.

18. Capillary mat Trickle system Flood irrigation

19. Two ways fertilizer can be applied: • Dry fertilizers • Water-soluble fertilizers/greenhouse watering system liquid. • The greenhouse watering system is the most common means of applying liquid fertilizer to crops.

20. Three types of systems used in applying liquid fertilizer: • Venturiproportioner – draws fertilizer through a small tube that connects the water hose to the fertilizer concentrate. • Positive displacement pump – maintains a uniform proportion of fertilizer to water ratio, regardless of the water pressure or rate of flow. • Eductor –places the fertilizer concentrate in a pliable bag surrounded by water pressure; as the pressure increases it forces the fertilizer through a metering system and into the water line.

21. The amount of fertilizer applied per application depends on strength of the concentrate, dilution ratio of the injector, and the amount of water.

22. Greenhouse fertilizers are measured by the number of parts of nutrients to a million parts of water, or ppm, part per million. • PPM is determined by percent of element in fertilizer X 75. • Growth retardants are sometimes needed because plants get too tall to make desirable potted plants. • The conditions of high temperature and high humidity, coupled with close spacing of a monoculture, make pest control necessary in greenhouse production.

23. Exclusion – prevent pests from becoming established in greenhouse. • Eradication – remove or eradicate pests. • Protection – place a barrier between crops and pests. • Resistance – selection of a resistant variety of plant. • No spray, dust, or fumigant kill 100% of the pest population.

24. Pest control in greenhouses is complicated by two factors: • Complex life cycle of many insects and some fungi that allows them to be unaffected by many chemical pesticides throughout much of their lives. • The rapid development of resistance to particular pesticides that characterize some pests, especially hosts.

25. To avoid the buildup of resistant pest populations, a grower must rotate the choice of pesticides frequently.

26. Ways greenhouse growers apply chemical pesticides: • Systemics – remain in the plant and kill the pest when it arrives. Applied as a soil drench or as foliar sprays. • Sprays – material is mixed with water in a hydroulic sprayer and applied to the foliage. • Dusts – covers large areas of crops quickly and less expensively than sprays. • Aerosol bombs – material is packaged in a container with a propellant liquid or gas.

27. Smoke fumigants – pesticide is packaged with a smoke producing material that disperses the pesticide. • Steam line vaporizers- pesticide is painted onto cold steam lines and the steam is turned on. • Foggers – the grower mixes the pesticides in an oil solvent and fills the fogger which heats and disperses the pesticide. • Misters – the pesticide is mixed with a solvent that evaporates quickly once out of the mister.

29. Safe application of pesticides in the greenhouse or elsewhere requires an understanding that: • Health of the plant is more important than killing the pest. • Health of the greenhouse staff and consumer are more important than the crops or pests. • The first rule of safe pesticide use is that people are more important than plants or pests.

30. Integrated pest management (IPM) uses methods other than just pesticides to protect plants. It uses temperature and humidity control, resistant varieties, screens and other barriers, monitoring devices, predatory insects, and pesticides to keep problems down.

31. The region is important when selecting crops to grow. Different regions have different temperatures and different natural pests. A plant may not respond well to pests that it has never encountered before, or it may not survive in the wrong climate.