Alternative Production - Season Extension Methods; Gardening Guidebook for Missouri

8/9/2019 Alternative Production - Season Extension Methods; Gardening Guidebook for Missouri

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Alternative Production:Season Extension Methods

•

Freezes vs. Frosts – Advective Freezes

• Strong Winds Bring Colder Air

• Sky May Be Cloudy or Clear

– Radiation Frosts• Clear Skies & Calm Winds During Night

• Higher Risk of Frost With Low Dew Point

Extend Growing Season

• Plasticulture

• Plastic Mulches

• Floating Row Covers

• Low Tunnels

• High Tunnels

• Cold Frames

• Hotbeds

Plasticulture

• Integrated System

– Plastic FilmMulches

– Drip IrrigationTape

– Row Covers

– Low Tunnels

– High Tunnels

Plastic Mulch

• Numerous Benefits – Earlier Crop Production

– Higher Yields

– Cleaner Produce

– Efficient Use of Water & Fertilizers

– Reduced Erosion

– Potential Decrease in Diseases, Insects

–

Fewer Weeds – Reduced Soil Compaction

– Opportunity for Double or Triple Cropping

• Disadvantages

– Costs & Management Time

– Removal From Field & Disposal• Machines Expensive

• Few Recyclers

– Dirt on Plastic

– UV Degradation

– Cost to Collect & Sort

– Lack of Reliable End-Use Markets

• Used Commercially on Veggies Since Early1960s

• Helps Growers in Northern & High-AltitudeClimates Harvest Summer Crops

• Requirements for Success

– Level Beds

– Tightly-Laid Plastic

–

Drip Irrigation• Restrictions for Certified

Organic Growers

• Many Colors, Weights, Sizes

• Black Most Common

– Suppresses Weed Growth

– Reduces Soil Water Loss

– Increases Soil T

– Improves Veggie Yield


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• Clear – Allows Greater Soil Warming

– Used in Cooler Regions of U.S. or for Early-Season Production

– Weeds Grow Under Clear Mulch

• White, White-on-Black, Silver Reflecting – Slight in Soil T°

– Maybe Helpful When Soil T Are High

• Infrared-Transmitting – Weed Control Like Black Mulch

– Medium at Warming Soil

– Brown or Blue-Green

• Red – Performs Like Black – Tomato Crops Average 12% Marketable Yield – If Environmental Conditions Ideal, Minimal Response

From Tomatoes – Less Early Blight & Suppresses Nematodes

• Additional Colors – Each Reflects Different Radiation Patterns Into

Canopy – Increased Yield for Some Crops – May Affect Insect Populations

• Photodegradable Film – Similar in Qualities as Other Black or Clear – Buried Edges Must Be Uncovered & Exposed to

Sunlight – Not Allowed in Organic Production

Floating RowCovers

• Lightweight

• ‘Float’ Over Most Crops

• Spun-Bonded Fabric Permeableto Sunlight, Water, Air

• Microclimate Similar to Interiorof Greenhouse

• Protection From Drying Winds

• 2 to 8° Frost Protection• 0.3 to 2 oz./sq. yd.

• Heavier = Greater Frost Protection

– Various Lengths & Widths

– Wider Labor-Efficient

– Can Be Laid Mechanically

– Can Weight Edges With Rebar

– Leave Slack in Cover so Crop to Grow

– Row Covers Over Bare Soil Create FavorableEnvironment for Weeds

– Heavier Covers Can Last 3-4 Years

– Lightest Covers Primarily Insect Barriers

• Easily Damaged by Animals

• Seldom Reusable

• Little Effect on T° & Light Transmission Dennis Hatfield Photo

• Can Leave Covers on Mostof Growth if Crops Self-Pollinated or Leafy

• Can Get Hot Under Covers – Tomatoes & Peppers Drop

Blossoms if T° Above 86

• Must Remove at Floweringfor Insect-Pollinated Crops

– Can Replace AfterPollination

• Can Use Cover Removal for Hardening-Off

• Covers Removed Before Spring CropsMature

• Covers Remain on Mature Fall Crops – May Result in Leaf Abrasion in Windy Conditions

– Wire Hoops or Rods

• Store away From Sunlight When RemovedFrom Field


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Low Tunnels

• Hoop-Supported RowCovers14-18 Inches High

• Wide Enough to Cover 1 Bed

• Growers Often Use 2 3-FootWide Plastic Sheets StapledTogether at Top for TrellisedCrops

• Similar Benefits as Floating Row Covers

– Not Permeable to Air or Water

• Slitted Row Covers

– Pre-Cut Slits for Hot Air to Escape

– Slits Remain Closed at Night to Reduce HeatLoss

•

Punched Row Covers – Small Holes Punched About 4 Inches Apart

– Trap More Heat Than Slitted Tunnels

• Growers Often Use 2 3-Foot Wide PlasticSheets Stapled Together at Top for TrellisedCrops

High Tunnels

• Unheated, Plastic-CoveredGreenhouses

• Commercial GreenhousesCost up to $20/sq. ft.

• High Tunnels Cost as Littleas $0.50/sq. ft.

• Tall Enough to Walk in

Comfortably• 14-30 Feet Wide, 30-96 Feet

Long

• Low Cost Way to Extend Growing Season

• Improves Profitability

• Increase Early Tomato Yields

• Lettuce Through Fall & Winter

• Higher Quality Produce

• Most Passively Ventilated Via Roll-Up Sidewalls

• End Walls Can Be Opened or Removed

Andy Read photo

• Usually No Heat

• Supplemental Heat on ColdNights or to Extend Season

• Usually Single Layer of PolyProvides 1 Hardiness Zone ofProtection

• Row Covers Within High TunnelsProvide Extra Protection

– 2nd Layer Provides Another Zone ofProtection

Andy Read Photo

• Crops Typically Grownin Ground Beds WithAmended Soil

•Irrigation Needed

• Some High TunnelsErected on Skids

• Weed Control Is byHand or Use of Mulch

• Low Cost Drip System

• Maximize Space

Andy Read Photo


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• Manure Hotbeds

– Dig Pit About 2.5 Feet Deep

– If Earth Walls Are Firm, NoInside Wall Needed

– Start in Early March

– Use Fresh Horse Manure

– 4 Cubic Yards Needed for Single-Sash 6x3 Hotbed

– Pile Manure Near Hotbed

– Turn Heap Every 3 or 4 Days

– Place in Pit When Entire Pile Begins to HeatEvenly

– Spread Evenly in 6-Inch Layers

– After 2 Feet Deep With Manure, Spread ThinLayer of Straw Over Pile

– Add 4 to 6 Inches of Seedbed-Suitable Soil

–

Insert Soil Thermometer so Mercury Extends WellDown Into Soil

– Sash Should Remain Tightly Closed

– Thermometer Will Register High 1st Few Days

– Hotbed Ready to Use When Soil T°Cools to 75F

• Hotbeds With Wood Chips – Wood Chips Can Be Used in Deep Frames

– Add Generous Sprinkling of Quicklime on Top ofeach 6- to 8-Inch Layer of Firmly Packed WoodChips

– Repeat Until Depth of About 30 Inches

– Place Thin Layer or Leaves or Pine Needles on Topto Prevent Topsoil From Washing Into Chips

– Add Soil

• Cleaning – Yearly

– Half-Rotted Medium Can Be Mixed With Topsoil &Sand for Use as Excellent Compost in Garden &for Potting

• Electric

– Insulated Electric Cable May BeBuried in Soil to Provide Uniform Heat

– Dig Pit About 12 Inches Deep

– Pit Needs to Be About 2 Feet Longer and 2Feet Wider Than Dimensions of Frame ThatWill Be Set on Top of Filled Pit

– Fill Pit With 6 Inches of Gravel

– Place Frame Directly on Bed

– Add Soil Around Outside of Frame for

Insulation – Place Layer or Burlap or Peat Moss Over Gravel

– Spread 1 Inch Sand Over Surfacepubs.ext.vt.edu/426/426-381/426-381.html

– Lay Electric Cable on Sand in Uniform Loops

– Need About 60 Feet of Flexible, Heavily Insulated110-Volt Cable for 2-Sash Hotbed• 6 Feet Square

– Will Make 10 Coils Spaced About 7 Inches Apart – Connect Ends of Cable to Thermostat

– Place Thermostat Inside Frame• Switch Box on North Side of Bed

– Maintain Uniform Temp• 60 – 75F Tender Plants, 50 - 60F Half-Hardy Plants, 45 -

60F Hardy Plants

– 2-Sash Hotbed Needs About 400 Watts to ProvideAdequate Heat in Zone 6 or 7

– Around 1 Kilowatt Hour/Square Yard ofHotbed/Day

• Disadvantages of Hotbeds

– Current May Fail Due to Severe Storm or OtherEmergency

–

Higher Likelihood of Damping-Off Since PlantsGrowing in Hot, Humid Environment

– Plants More Sensitive to Sudden Fluctuations inT°

– Be Careful With Ventilation & Watering

– Harden Off Plants Before Transplanting Outside

Documents

Alternative Production - Season Extension Methods; Gardening Guidebook for Missouri