Grow Your Own, Nevada! Spring 2013: Efficient Irrigation for the Home Vegetable Garden
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Semelhante a Grow Your Own, Nevada! Spring 2013: Efficient Irrigation for the Home Vegetable Garden
Semelhante a Grow Your Own, Nevada! Spring 2013: Efficient Irrigation for the Home Vegetable Garden (20)
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Grow Your Own, Nevada! Spring 2013: Efficient Irrigation for the Home Vegetable Garden
- 1. Efficient Irrigation for the Home Vegetable Garden Heidi Kratsch State Horticulture Specialist
- 2. What we will cover… • How much water do plants need? • How does water move in your soil? • Measuring water application • Types of irrigation systems
- 3. Why do plants need water? • Plants use light + CO2 and water to make sugar. • Sugars are used by the plant for growth or stored.
- 4. Why do plants need water? • Most vegetables are 80 to 95% water • Yield and quality suffer from lack of water
- 5. What affects water loss from plants? •Sunlight •Temperature •Humidity •Wind
- 6. Large leaves have more pores What our eyes see What our eyes can‟t see
- 7. Crop water use –example, corn
- 8. Critical water periods for vegetables • Beans – high water demand; need most critical during flowering and pod sizing • Corn – high water demand; peak demand during tasseling, silking and ear formation • Leafy vegetables – water most critical during head development • Tomato – Water needs increase with plant growth; uniform watering is critical during fruit development
- 9. Critical water periods for fruits • Apples, pears, peaches, plums, cherries – during flower formation, fruit set and final fruit swell • Raspberries and blackberries – during bloom and during sizing of fruits • Strawberries – at planting, during runner formation and during flower bud development
- 10. There are two aspects to watering • How much to apply at one time… • How often to apply it.
- 11. How to water your plants • Applying too much water at one time leaches nutrients from the soil. • Applying water too often suffocates roots. Flooding plants deprives roots of oxygen
- 12. How much do I water? • Sandy soils need water more frequently. • Water more frequently in hot weather. • New seedlings or transplants need more frequent watering. • Large, deep-rooted plants need deeper watering.
- 13. How much water to provide… • 1 to 2 inches per week during hot weather • Depends on: ▫ air temperature ▫ size of plant ▫ Stage of development
- 14. Measuring sprinkler irrigation amount Catch-can test: • Scatter soup cans around the garden • Turn on irrigation • Measure amount of water in cans after 15 minutes of irrigation
- 15. Measuring your irrigation amount • Say you measure ¼ inch after 15 minutes • Assume garden needs 1.5 inches water per week • You might water for 15 minutes 6 times per week, or for 30 minutes 3 times per week
- 16. How often to provide water • Rate of evaporation • Rate of movement in soil • Affected by soil texture
- 17. CLAYSILTSAND Water movement through different soil types 0 1 2 3 Depth (Feet)
- 18. Affect of soil texture on water-holding Sandy soil Clay soil • Each foot of soil depth holds about ¾ inch of available water • Each foot of soil depth holds about 2 to 2-1/2 inches available water Clay soils have a greater water-holding capacity than sandy soils.
- 19. Checking soil moisture • Feel method • Stick method • Soil sample • Soil moisture probe
- 20. Get your hands in the soil! • Dig down 2 to 4 inches in the soil • Soil near field capacity will feel moist but not wet • Plants may experience drought when the soil feels dry and crumbly
- 21. Indicator plants • Squash Cucurbita hybrids • Tomato Lycopersicon hybrids • Wilting leaves and/or stems • (May also happen in late afternoon sun – they will recover)
- 22. What’s wrong with my plant? Diagnostic Chart CAUSE Over watering Under watering Nutrient deficiency SOIL CONDITION Wet Dry Wet or dry LEAF CONDITION Yellow, falling off Wilted, curled, tip burn Yellow, but remains on plant
- 23. Water problems • Blossom end rot occurs on blossom end of fruits • Caused by calcium not getting up to fruits • The problem is inconsistent watering • Apply mulch to hold water in the soil • Do NOT apply lime or gypsum. Water fluctuations can also cause fruit cracking. Blossom end rot
- 24. Watering methods Sprinkler irrigation • Automatic • Less efficient due to: ▫ Wind ▫ Evaporation ▫ Weeds
- 25. Watering methods Hand watering • Time consuming • Generally only wets upper layer of soil • Are you providing consistent amounts to each plant?
- 26. Watering methods Soaker hose • Easy • Inexpensive • Saves water • Hoses must be replaced often • Best in a flat area with rows not longer than 25 feet
- 28. Why drip irrigation ? • Less loss to evaporation • Increases water infiltration on slopes • Reduces leaching or runoff • Reduces weeds
- 29. Drip irrigation methods are low pressure (10-30 psi) • Drip emitters • Micro-spray emitters Microspray emitter External drip emitter
- 30. Drip Emitters • External versus internal emitters • Should be pressure- compensating • Deliver water at 0.5- 2.0 gph External emitters Internal emitters
- 31. Microspray emitters • Available from 3 to 30 gph • Larger water droplet than sprinkler emitters • More efficient than conventional sprinklers • Good for low crops or beneath tall crops
- 32. Drip Irrigation Terms • Main line • Sub-main line • ½-inch supply line • ¼-inch feeder line • Pressure regulator • Filter • Backflow preventer (anti-syphon) • Control valve(s)
- 33. Basic elements of a drip system
- 34. Tubing arranged in lines with end caps
- 35. Tubing arranged in a circle
- 36. Putting it all together
- 37. Plumbing off main line Main line riser Automatic timer Filter Pressure regulator
- 38. Automatic Timer
- 39. Multi-station timers and manifolds
- 40. Drip inline emitter spacing • Standard 12- inch or 18-inch emitter spacing
- 41. Drip lines in a vegetable garden Mulch to prevent water evaporation
- 42. Stake tubing to keep in place Internal emitter
- 43. External emitter staked on a riser Attach an external emitter to the end of ¼-inch feeder line and stake with a riser to mist plants.
- 44. Ends must be capped or clamped to maintain water pressure. Hose end clampHose end cap
- 45. Some EASY math… The maximum pressure handled by a drip irrigation system is 25-40 psi (pounds per square inch). If in doubt, install a pressure regulator: • The total gph flowing through emitters should not exceed 75% the total flow rate of the drip tubing: ▫ Number of emitters × GPH per emitter = total GPH through emitters ▫ Example: 300 1-GPH emitters can be supported by system with a 400 GPH flow rate.
- 46. To measure flow rate for drip: • Get a 5-gal. bucket and a stop watch. • Put bucket under the faucet. • Turn on faucet and start timer. • Calculate how long it takes to fill the bucket. • 5 gal / (45) seconds × 3600 sec/hr = (400) GPH flow rate.
- 47. Mulching • Organic mulches ▫ Straw ▫ Wood chips ▫ Shredded bark ▫ Grass clippings (herbicide-free) ▫ Leaves • Dense plantings • Plastic mulch
- 48. Plastic mulch • Black polyethylene plastic film for dry climates with cool springs • Drip irrigation laid under the plastic • Controls weeds • Warms the soil for an earlier crop
- 49. Subsurface drip systems • Uses buried drip tubing – 6 to 24 inches deep • Saves water and improves yields • Higher initial investment • Good for hot and windy areas • Efficiency depends on “wickability” of soil • Not good for quick-draining sandy or gravelly soils • (Great!) potential for rodent damage
- 50. Gravity drip bucket systems • Buckets need to be elevated at least 3 feet from the ground • Use with drip irrigation tape • Fill buckets once daily • Use where water availability is limited
- 51. Olla or clay pot irrigation
- 52. Watering from a well system • Backflow protection • Determine steady state flow rate and pressure. • Insert a delay between stations that allows the well to recharge.
- 53. Septic systems: can I plant on or near my leach field? • No! Do not site your vegetable garden (including fruit trees) over the leach field. • Roots may damage the leach field. • Crops may be contaminated with bacteria or viruses. • Root crops (carrots, potatoes) may be directly exposed to human pathogens. • Fruits and vegetables should be planted at least 10 feet from a septic system or leach field to avoid bacterial contamination.
- 54. Artichokes • Grow from transplants or seed (transplant 3-4 weeks before FF date). • Requires cool temps to initiate a flower stalk. • Drip irrigation is best; keep soil moist; roots are shallow. Artichokes are flower buds. „Green Globe‟ heirloom
- 55. Beans and peas • Water: ▫ Keep soils moist but not wet. ▫ Water most critical during flower and pod development. ▫ Dry beans: reduce water as seeds begin to mature „Blue Lake‟ – pole type Lack of flower development or “stringy” beans indicate water or heat stress.
- 56. Beets • Grow from seed. • Water regularly using drip irrigation to keep soil moist. • Moisture fluctuations cause root cracking. • Weed control is essential! „Detroit Dark Red‟ Heat and water stress may cause woody beets.
- 57. Carrots Water ▫ Use drip irrigation if possible. ▫ Avoid over- watering to prevent hairy roots and forking. „Imperator‟ Uneven watering causes root cracking.
- 58. Broccoli • Best grown as transplants. • Water: ▫ Deeply and infrequently to encourage deep roots. ▫ Use mulch to conserve water and control weeds. „Calabrese‟ heirloom “Buttoning” (premature flower buds) soon after transplant can be caused by water stress.
- 59. Brussels sprouts • Grow from seed started indoors. • Water: ▫ Deeply and infrequently to encourage deep roots. ▫ Use drip to provide even moisture. Use mulch. „Long Island Improved‟ Uneven watering promotes splitting, bitter taste and tip burn.
- 60. Cabbage/brussels sprout tip burn • Calcium not transported to rapidly expanding tissues. • Common in sandy soils. • Caused by any condition that favors rapid growth. • Maintain even moisture levels. Tip burn on brussels sprout
- 61. Leeks • Water: ▫ Roots are shallow; provide water regularly. „American Flag‟ Weed control is especially important during the first 2 months of growth.
- 62. Cucumbers • Love sandy soils and lots of room! • Water deeply by drip or basins • Over- and under- watering causes: ▫ Bitter fruits ▫ Pointed ends ▫ Misshapen „Marketmore‟ Cucumber plants are vining and benefit from a trellis.
- 63. Potato • Grown from “seed pieces” • Soils must be 50 F • “Hill” soil around plants as they grow to prevent tuber “greening.” • Water: ▫ Deep, regular watering with drip irrigation. ▫ Reduce water as leaves yellow Irregular soil moisture causes abnormal tuber growth. Many potato varieties will grow in northern Nevada.
- 64. Questions?
Notas do Editor
- Photosynthesis is one of the hallmark functions of a plant, and is a key difference between plants and animals (animals can’t photosynthesize, of course). Think about it this way: humans and animals can move around their environment to attain food and water and to escape uncomfortable or unsafe conditions. Plants can’t – they’re rooted in place and so must be able to meet all their needs using the tools they have. Photosynthesis occurs mainly in the leaves of plants, although it can occur in any part of the plant that is green. Photosynthesis happens in the chloroplasts where the green pigment, chlorophyll, absorbs light. Plants use carbon dioxide taken up from the atmosphere through leaf stomata, water taken up through the roots, and sunlight to produce sugars (also known as carbohydrates). Plants use the carbohydrates from photosynthesis to grow. Greenhouse growers can increase the rate of photosynthesis of horticultural plants by enriching the greenhouse environment with carbon dioxide. This cause plants to grow faster. We’ll take more about this later in the semester when we cover greenhouse production.
- Most vegetables don’t like fluctuations in water availability
- mainline, valve, sub-main, backflow preventer, pressure regulator, filter, tubing adapters and fittings, drip tubing, emitters, and end caps.
- The mainline is the pipe that runs from the water source – typically your outdoor faucet - to the valve; and the sub-main runs from the valve to the point where the drip tubing is connected. Generally, sub-mains are used only when there are multiple lines of drip tubing and zones feeding off of the same mainline water source. The combined length of the mainline and sub-main should not exceed 400 feet.The valve controls water flow into the system and can be set for either automatic or manual control. Backflow preventers are necessary to ensure that irrigation water does not flow back into the pipes and contaminate your main water source. Pressure regulators are only necessary if your water pressure is over 40 pounds per square inch. If you do not know your water pressure it is a good idea to install one just in case. Filters keep dissolved substances in your water from clogging the emitters over time. Install filters either at the emitters or at the water source to protect both the valve and pressure regulator in addition to the emitters. It is best if the filter has at least a 150 mesh screen or higher. Tubing adapters and fittings are used to attach the drip tubing to the rest of the system. It is important that these are the right size for the tubing to prevent them from blowing apart under pressure.
- Because small amounts of water are applied slowly, drip irrigation is designed to run daily unless it rains. How long to run the drip irrigation system will depend on how much water your plants require per day and the flow rate of your emitters. Water is applied either once or twice a day. Early morning is the best time to water because there will be less evaporation. Watering in the evening increases the plant’s susceptibility to disease.
- Boron, weeds