DIY: Irrigation The Basics for Small Home Gardens

Transcription

1 DIY: Irrigation The Basics for Small Home Gardens Master Gardeners February 19, 2013

2 Providing in the Garden The main purpose for irrigating is to supply needed water for crops Most vegetables need between 1/3 per day or 2 inches of water per week Can use a watering can, regular hose, sprinkler, irrigation system, drip hose Most people OVERWATER!! Account for natural precipitation

3 Where to place a rain gauge Rain gauges should be placed in an open area away from trees, buildings, and other structures, as this may cause an inaccurate reading. A general guideline to follow is placing the rain gauge twice as far away from the height of an object such as a tree.

4 Rainwater Capturing Systems According to EPA, 50-70% of total household water is used for landscape irrigation and other outdoor activities. The most practical way to use capture in gardens and landscapes is by drip irrigation using gravity. # of gallons/1000 square foot area during rainfall events Rainfall depth (in) Volume of water (gal)

5 PM Rainwater Catchment from a High Tunnel for Irrigation Use

6 2.5 5 feet spread Soil Type and Irrigation SAND SILT 5 9 feet spread CLAY feet spread Water spreads differently in different soil textures

7 Jar Test

8 Where do plants get their water from in the root zone? Adapted from PNW 475 by A. Miller

9 Garden Crop Rooting Depth Root Zone Crop Depth (ft) Beans 2.0 Corn 2.5 Onions 1.5 Potatoes 2.0 Peas 2.0 Tomato 2.0 Plants will effectively take up water from all depths of their root zone (70% in the upper 50%) check soil moisture at 1/3 rooting depth

10 You know about how much, but when, or how often? Most plants become stressed when available soil moisture drops below 60% You can check soil moisture several ways: soil moisture sensors feel method

11 The Soil Moisture Feel Method % 50-75% 25-50% While drought can impact plants, over-watering creates many concerns such as: Increases risk of pollution from yard and garden care products. Encourages shallow root zones and increases plant susceptibility to disease.

12 Water Conservation (or water management BMP s) Reduce need for watering by: 1) mulching 2) improving soil structure 3) irrigate only when the plants need water 4) drip-irrigation

13 Mulching Protects the soil from erosion Reduces compaction from the impact of heavy rains Conserves moisture, reducing the need for frequent watering Maintains a more even soil temperature and moisture level Prevents weed growth Keeps fruits and vegetables clean Keeps feet clean, allowing access to garden even when damp Provides a "finished" look to the garden

14 Improving Soil Structure Don t Rototill especially when soils are wet!! ADD Organic Matter!!!

15 Using sprinklers in the garden Convenient Increases chances of leaf burn Disease and pest issues increase Not efficient, 60-80%

16 Measuring sprinkler output Step One Checking Sprinkler Distribution Pick a calm day with little or no wind to check coverage. Select five identical straight sided containers, (coffee cans, cat food cans, etc.), then place them level on the lawn, 3 to 4 feet apart in a straight line. Turn the water on for 15 minutes. After 15 minutes, turn off the water and measure the amount of water in each can to the nearest 1/8 inch. Usually, each can will contain a different amount of water. If the water level between cans differs more than 1/4 inch, inspect the sprinkler nozzles for dirt or rocks that may be blocking the opening. With underground watering systems, it may be necessary to replace or add sprinkler heads, or divide an existing system into two or more lines. Some underground systems can be adjusted for more water coverage.

17 Measuring sprinkler output

18 Measuring sprinkler output Step Two Measuring Sprinkler Output To measure the amount of water (in inches) that your sprinkler puts out over a 15-minute period. Use five identical straight sided containers placed level on the lawn, space 3 to 4 feet apart in a straight line away from the sprinkler. Turn the water on and let it run for 15 minutes. Using a ruler, measure and record the water accumulated in each can to the nearest 1/8 inch. Pour the four cans into the fifth, and measure the total water content. Then divide that total by 5. You now have the average amount of water the sprinkler puts out in 15 minutes. Use this average to time your watering. Run the water only long enough to deliver water, two to three times a week.

19 Measuring sprinkler output Can #1 3/8" (3/8") Can #2 3/8" (3/8") Can #3 1/4" (same as 2/8") Can #4 1/2" (same as 4/8") Can #5 3/8" (3/8") Total 1 7/8" (same as 15/8") Divide the total inches (15/8") by 5 = 3/8" to get the average inches of water per can.

20 Soaker Hoses Not as efficient as drip Needs filter and pressure regulator, hard water can clog Cannot bury or use on slope, can mulch over <50 ft best = uneven distribution

21 Drip Irrigation Drip irrigation is an easy way to water your yard in the most efficient, least labor intensive manner. With a timer, it can be an automated system that will mostly take care of itself, requiring only a bit of maintenance to keep things running smoothly. Application efficiency about 90-95%

22 Types of Drip Equipment Drip tubing with built-in emitters Drip tubing or poly pipe with punch-in emitters Drip tape with built-in emitters

23 In-line Emitters, AE=90-95%

24 Punch-in Emitters Allow watering only at each plant (eg. Best for plants spaced several feet apart Emitters should be punched in on the top or side of tubing to minimize plugging Usually 1-2 gal/hr emitters work well in silt or sandy soil For fruit trees, add multiple emitters to the tubing on each side of tree as it grows

25 Goof plugs (poly pipe)

26 Drip emitters and Spaghetti tubing

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28 Drip Tape with Built-in Emitters Less expensive Can also be buried More subject to damage from hoes or rodents Provides a line source of water - good for irrigating rows in a garden

29 Drip Tape Specs 4 mil to 25 mil thickness Emitter spacing 2 up to 36 Flow rates: usually X gpm per 100 ft.25 up to 1.5 gpm/100 ft Filtration: 200 mesh for all tape Pressure: psi ½, 1, and 2 tape width (for vol)

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31 Soil Wetting Patterns Depend on emitter location max wetting at or near soil surface for surface location max wetting at depth of tape for subsurface location thickness of wet soil above emitter is about 1/4 wetted width for sandy soils and about 1/2 wetted width for silt or clay soils

32 Depend on soil type Soil Wetting Patterns sandy soils: water moves deep with narrow wetted width. Max wetted width about silt or clay soils: water moves slightly deeper than wetted width. Max wetted width about inches

33 Soil Type and Irrigation Consideration is the type of soil that you have is important for determining drip irrigation details, spacing and flow of emitters Clay Soil = water from emitters will tend to move farther away from source, you might use a lower flow emitter (1/2 gph to 1 gph) Sandy Soil = water moves further down but closer to source, you might use a higher flow (1 to 4 gph) emitter while in a clay soil

34 Good for row crops

35 Great with plastic or row cover

36 Simple layout

37 Drip tape couplings

38 Tees & tubing

39 Elbows

40 Drip tape ends - plugs

41 Drip tape to hose connector

42 Shut-off valve

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44 Flower pots

45 Zone sprinkler head adapter

46 Spray tubes & misc.

47 Foggers

48 Adjustable dripper

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58 Bucket kits

59 inf/infiltration_planter.pdf Infiltration and Flow-Through Planters

60 UAF CES Publications Catalog

61 Bottom line.. Be creative with the space, but make it functional. Irrigation timing and amount should depend on soil type and form of irrigation Stick your fingers in the soil as often as necessary. Don t forget to MULCH!!!