Season extension: Managing production risks and expanding ... · Season extension: Managing production risks and expanding markets Neith Little Urban Agriculture Extension Educator

Season extension:Managing production risks

and expanding marketsNeith Little

Urban Agriculture Extension EducatorUniversity of Maryland Extension, Baltimore City

Adapted from presentations by David Martin, UMD Extension, Baltimore County

Guy Kilpatrick, UMD Terp FarmBryan Butler, UMD Extension, Carroll County

UMD Programs are Equal Access

Learning goals:

• What’s your experience? What do you want to learn?

• By the end of this session:– Consider what type of season extension

fits your farm and goals– Be aware of key pitfalls and tips for

success– Know where to go to learn more


Why season extension

Production risk management• Season extension tools can be used to

– Mitigate climate variability– Shelter from pests and diseases– Reduce weed pressure

• BUT poor management can make things worse– Temperature management– Humidity


Why season extension

Marketing risk management• Season extension tools can be used to

open new markets by– Extending production season– Enabling production of niche crops


But…

Financial risk management• Season extension tools require

investment and maintenance• Make sure you factor these costs into

your enterprise budget. Will the benefits outweigh the costs?


Types of season extension techniques

• Crop mulching systems

• Row covers and low tunnels

• High tunnels• Greenhouses


Crop mulching systems

Purpose: Cover soil around desirable plants to maintain or improve favorable crop production conditions:• Weeds• Soil temperature• Soil moisture• Pests• Diseases



History• Organic Mulches

– Straw, Composts, Wood Chips, – Corn Cobs, Pine Needles

• Interest in Paper Mulches since 1920• “New Plastic Products”



Organic mulches• Large bulk and weight

– difficult for larger scale farms

• High labor costs• Low equipment

investment• Weed suppression• Moisture retention• Reduce soil splash



Plastic mulches• Easier to scale up• Low labor costs• High equipment

investment• Efficient fertilizer use• Weed control• Moisture retention• Increased soil temperature earlier crop



Definitions:• Plasticulture – Use of plastic products

(usually plastic films) to enhance plant production

• Plasticulture System – combining several production inputs to enhance quality and quantity of plant production



Parts of a plasticulture system• *Plastic mulch film• *Plastic trickle irrigation tubing• Injector for fertilizer • Raised beds for temperature &

H2O management• Row covers and tunnels

* Basic ingredients of a plasticulture system


Bed formerPlastic mulch layer


Plastic mulch layer

“Water wheel” transplanter



Stake pounder

Sprayer for row middles with shields

Mulch lifter

Plasticulture systems

Plasticulture system installation tips• To warm soil, apply clear plastic 7-10 days prior to

planting• Loose, moist soil best• Lay plastic tight• Raised beds can help• Windy days air pockets• Bury edges well, > 6”• Apply fertilizer before laying plastic• Install trickle tube at same time plastic is laid

Disposal can be problem…• Land fill• recycling• fuel

Plasticulture systems


Not all plastic mulches are created equal

Biodegradable usually means photodegradable

Rolled paper mulchreduces use of plastic, but can be fragile



Effect of color:• Black is standard, but

clear and white-on-black also widely used

• Color affects– Light reflection (1)– Light absorption (2)– Light transmission (3)

Sun Light


Reflects most of solar radiation

Lowest soil To

Weed Control is variable

Aluminized plastic

Transmits 85 to 95% of solar radiation

Highest soil To

Weed problems

Clear plastic Absorbs

most of solar radiation and transmits to soil

High soil To

Excellent Weed control

Black plastic

Crop mulching systems: effect of color

Highly Reflective Films

Source MulchFilm.com

Grey or silver films Aluminum stripes

on black film

Used mainly to repel aphids Delay the onset of virus

diseases in cucurbits

Crop mulching systems: effect of color



Floating row covers and low tunnels• Most commonly made of spun polyester • Low tunnels might be made of clear plastic• Purpose:

– Temperature protection– Pest protection

• Difference:– Row covers “float” on top of plants– Low tunnels go over small metal hoops



Floating row covers• Quick, short-term

response to temperature or pest danger

• Greater risk of blowing away, or damaging foliage

Photo credit: WI Master Gardeners



Low tunnels

• More effort, but longer-term protection

• Over small hoops• Bury edges• Can be plastic or

spun polyester



High tunnels

Compared to greenhouses • Have low up front

cost• Low maintenance

cost• Low operational cost• and high versatility



• Traditionally hooked upto water, no electricity.

• Roll up sides forpassive ventilation.

• Removable ends for tillage with small tractors.

• Crops usually in soil. • Weed control by controlled irrigation, mulches.• Disease problems nominal because crop stays dry.


High tunnels are versatile

• Holding area – store plants from a greenhouse• With tables can be used for “curing” squash, sweet

potatoes• Protection from late spring frosts and fall cold

snaps• Foliage stays dry, less hospitable for diseases• Facilitates production of

high-value “specialty” crops– cut flowers, ginger, turmeric,

raspberries, baby greens• Minimize weed problems• Pleasant working environment


High tunnels: tips for construction

Site selection: • Watch for

drainage problems


Aug-Nov ideal to put up structure

This allows for maximum flexibility in the spring


High tunnels: construction numbers

• Kits start at 20’ X 48’, for $4,000 to $5,000 plus shipping and construction

• Funding available from USDA-NRCS High Tunnel Initiative



Buying the correct structure will ensure a long and productive life for your tunnel.

Wind Damage

Snow Damage

Parts of the High Tunnel

Purlins

Hip board

Base board

Roll up bar/handle

Hoop

Ground post(underground)

WIDTH PURLINS WALL HT

PEAK HT

PIPE DIA

12' 1 6'0" 9'0" 1.660"

14' 1 6'0" 9'3" 1.660"

17' 3 5'6" 10' 1.660"

21' 3 5'6" 11' 1.660"

26' 5 6'0" 12'6" 1.900"

30' 5 6'0" 13'3" 1.900"

Source; Ledgewood Farms

Suggested design specs

Attention to detail during set up will pay off in the long

run.

Roll-up bar makes rolling up sides much easier

Straps to hold down rolled up sides help prevent wind damage

Note the roll up bar

Is this attention to detail?

6/9/2005

High tunnel management

• High level of management a highly productive tunnel

• The opposite is also true

120 degrees F

Ventilation is a MUST

Temperature management is vital

Cropping Potential

Lettuces

• Early• Clean• Reduce bitter

flavor from too much sun

• Easy to cut and package

Red and Yellow RaspberriesPrimocane (“fall bearing”) varieties produce

from mid-August through frost.

Strawberries

• Good fit for low or high tunnels

• Extend season• Protect fruit from

predators, insects, diseases

• Many creative ways to grow:– use space efficiently– protect from rodents.

Beyond basic tunnels

• Tunnels within a tunnel

• Floating row covers• Heat sinks• Active heating

– A heater designed for a greenhouse is preferable

– Be careful of fire risk– Exhaust properly

Fertigation through drip tape

Automated roll-up sides

What About Mobile Tunnels?Home Made Mobile Tunnel

• Fall Cover Primocane Red Raspberries• Winter cover annual strawberries• Spring early strawberry crop / move to tomatoes• Summer heirloom tomatoes

WMREC ExperimentalMobile Tunnel

Possible Benefits of a Mobile Tunnel

• 3 crops per year at the cost of 1 ½ tunnels

• Lower cost for high tunnel production

• Reduced salt build up• Easier to renovate the soil• Cooler in summer for raspberries• Increased crop options

Where to go to learn more about season extension

• University of Maryland Extension– FS-957 High tunnel production by Bryan Butler and Lisa Bauer.

www.bit.ly/UMEHighTunnels– Brambles page, w/ season extension information by Joe Fiola,

www.bit.ly/UMEBrambles

• Penn State Extension– High tunnel and plasticulture manuals available

www.bit.ly/PennSeasonExtension

• University of Minnesota Extension– Low tunnel strawberry production www.bit.ly/MNStrawberries

• USDA-NRCS High Tunnel Initiative– www.bit.ly/NRCSHighTunnels


http://www.bit.ly/UMEHighTunnels

http://www.bit.ly/UMEBrambles

http://www.bit.ly/Penn_season_extension

http://www.bit.ly/MNStrawberries

http://www.bit.ly/NRCSHighTunnels

Documents

Season extension: Managing production risks and expanding ... · Season extension: Managing production risks and expanding markets Neith Little Urban Agriculture Extension Educator