Season Extension
Early and Late
Keith VanderVelde
Marquette Ag Agent
Kingston-Feb 27, 2008
Methods of Season Extension
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Low tech to high tech
Plasticulture
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Cold frames – drip tape – high tunnels –
greenhouses
Low $ to High $$$$$
Light, water, wind, colors, bugs, benefits,
temperatures, fertilizers, plastic, wood, glass
and varieties
Variety Selection – Days to Maturity
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Easiest way to get earlier
crop
May be limited on varieties
May not be best flavor as
longer season crops
Earlier to market, better
price
Consumer may be tolerant
of smaller size/ less flavor if
they are the first available
Variety Selection – Days to Maturity
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Easiest way to get earlier
crop
May be limited on varieties
May not be best flavor as
longer season crops
Earlier to market, better
price
Consumer may be tolerant
of smaller size/ less flavor if
they are the first available
Time of Harvest
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Consider size of
vegetable at harvest
Early red potatoes
Small pickling
cucumbers
Small summer squash
Baby carrots
Cherry tomatoes
Differences Amongst Vegetables
New Vegetables
Arugula 42 Days
Lettuce Blend 40-70 Days
Swiss Chard 55 Days
Spinach Mustard 35 Days
Considerations with New Veggies
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Growing requirements for new crop
Samples??
Consider providing recipe cards
Suggestions for use
Information on nutrition
Engage the customer – “I bet you’ve never
seen this before”
Starting Seeds Plants Earlier
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Light very important – quality and duration
Fan on young seedlings – helps prevent leggy
plants
Temperature – daytime 60 - 70°F – nights no
lower than 50°F
Size of container – prevent root bound plants
Timing – getting plants in the ground in a
timely manner
Lighting Considerations
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Incandescent – not good for plants needs
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Fluorescent – supplement sunlight well
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Good for heat, day length control
Combination of cool white with warm white will
provide full light spectrum
Cool white bulbs are more efficient than grow
lights in providing supplemental light
High Pressure sodium and metal halide
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1/3 more efficient than fluorescent - costly
Cold Frames / Hot Beds
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Mini greenhouses
Old windows
Plastic film on wood
frame
Rigid plastic
Hinged top needed to
regulate heat
Cold Frames
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Don’t have to be
covered
Used to harden off
plants before going to
field
Can use lattice or snow
fence to shade plants
Other Cold Frame Use
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Earlier plantings of leafy greens
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Lettuce, spinach, swiss chard, parsley
Better in cool weather and lower light
Wintering containers – Early forcing of tulips,
hyacinths, daffodils and crocus
Force early spring
New markets???
Other Cold Frame Use
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Late Summer Seeding
Plant broccoli, pepper, spinach, lettuce
Early winter harvest
Something to market other than root
vegetables and winter squash
Hot Beds
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Heating Cable
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Hole 6 inches deep
Lay cable
Cover with sand
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Manure
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10 inch deep hole
Add horse or chicken
manure
Cover with window
screen
Cover with soil
Shade Houses
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Propagation of woody cuttings – some
perennials
In containers or in ground bed
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Misting may be needed
Finishing/conditioning plants – from
greenhouse before field planting
Row Covers
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Flexible transparent material
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Perforated plastic, spunbonded polyester – polypropylene
Floating or supported by hoops
Can cover one or more rows
Trap heat of day – warm air and soil
Wind protection, less moisture loss
May be insect barrier depending on type
Think of crop needs when deciding on type of row
cover – temperature needs, pollination, growth habit
Supported Row Covers
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Also Called Low Tunnels
Can use PVC pipe, heavy
wire
More labor needed
Support needed for crops
such as tomato, pepper and
summer squash
Weed control needed
between rows
Low Tunnels
Floating Row Covers
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Spunbound polyester or polypropylene
70 – 80% light, air and water transmission
Placed directly on crop
0.5 – 1.25oz. /sq yard
Covers under 0.5oz. – very little heat retention
Over 1.75oz. Significant light reduction
2° - 4° frost protection in spring, more
protection in fall
Floating Row Covers
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For large covers weigh down centers to
prevent damage with high winds
Insect control may improve
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Maggot control
Squash bug control
Remember needs for pollination
Don’t trap insect pests – CPB
2-6 weeks earlier depending on local
conditions
Floating Row Cover
Zip Houses
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Mini greenhouse
Ability to easier
regulate temperature,
light and ventilation
Frost protection down to
26°
Open and close easily
from end of row
Reusable for 2-3
seasons
Zip Houses
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Protects from heavy
rains, heavy winds and
small hail
20-30” wide and 21-25”
tall
Cut to any length –
strings stay ready to pull
500’ roll $158 + S&H
Zip Houses
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Zip House Opened
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Several hundred feet
opened with one string
pull
No dirt moved when
opening
Opens in seconds
Allows pollination
Can be sprayed thru
open top
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Zip House Closed
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Release strings at end of
row
Closed in seconds
Double layer walls
Protects from wind, rains
and blowing soil
Much earlier growth
Colored Plastic Mulches
Plastic Mulches
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Used for years in vary colors
Advantages – increased yields, earlier crops,
higher quality, weed control and enhanced
insect management
Work well with drip irrigation
High value crops – melons, tomatoes, peppers
cucumbers, squash, eggplant ……………….
Many considerations for color
Plastic Mulches 2
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Colors – black, white, clear, white on black,
red, green, silver reflecting, blue-green, brown,
yellow, ect.
Red and black raise soil temps comparably
Blue-green and brown warm soil like clear
without weed problem
Red, blue, yellow, gray and orange have
distinct optical characteristics and reflect
different radiation pattern into the crop
Plastic Mulches 3
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Blue and green plastic increased root:shoot
ratios in turnips
Yellow, red and blue increased green peach
aphids
Yellow attracted cucumber beetles
Silver repels certain aphid species and reduces
or delays virus in summer squash
White or grey may require herbicide for weed
control
Mulch Color and Tomatoes
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Penn State Study – ‘Sunbeam’ ‘Mountain
Supreme’
Best yields on black – worst on green infra-red
thermal
Blue, silver and brown reduced fruit sizes
Varieties differ in response to same colors
Colors affect microclimate in variety of ways
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Reflected wavelengh, temperature, moisture,
humidity, insects and diseases
Mistakes in Plasticulture
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Lack of firm uniform bed – hot air funneling
Loose plastic – can cover transplants, wind
Poorly placed irrigation tape – plant health, cut tape
when planting
Failure to operate drip system immediately after
planting
Not monitoring temperatures
Not calibrating fertilizer injectors/rates
Not removing row cover from cucurbit crops during
pollination
Hoop Houses
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High tunnel
Many manufacturers
Build your own
Anchored in ground
Many heights/lengths
Some large enough for
tractors
Sides and ends for
ventilation
Crops
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Anything high value
Anything with early season premium
Fruits and vegetables, cut flowers, etc
Keep a crop later in the season – extend
harvest
Starting plants earlier
Wind protection / temp modification over
winter – nursery plants, perennials and herbs
Penn State Research Facility
Dan Mielke – tomatoes, peppers and cukes
Hoop Houses
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Selling fresh local tomatoes in June
Give you months of extra hours in a growing
season
Cultivating spinach and leafy greens year
round
High Tunnel Houses
High Tunnel Houses
High Tunnel Houses
Benefits
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Extending cropping season
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August/September seeding – spinach, broccoli,
other greens
Harvest until December
Limited by sunlight w/out supplemental light
Mulch with straw and harvest root crops
throughout winter
One Growers Experience
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20 x 96 foot tunnel
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4 rows tomatoes
2 rows of peppers
1 row of cucumbers
Yields
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4,500 lbs of tomatoes
13 bu of peppers
300 lbs of cucumber
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Cost of tunnel - $2000
Sales > $5000
Outside Tunnel
Inside Tunnel
Strawberry Crop
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Started on 4/15/03 by lowering sides
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Picking started on 6/1/03 – tunnel
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Temperature monitoring critical
Use floating row cover on cold nights
6/11/03 – plastic mulch with row cover
6/26/03 – berries without mulch or row cover
Berries were sweeter, cleaner, less distorted, larger
Tunnel vs no-tunnel from 200 – 380 % increase in
yield
Strawberry Varieties
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Early Glow – 200% increase in tunnel
Honeoye – 380% increase in tunnel
Jewel – 330% increase in tunnel
Raspberry Crop
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Fall berries
First ripe berries inside or out September 26
October 1st outside crop froze
Tunnel berries produced until November 2
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Let berries freeze because of extended cold
weather
Too costly to heat for amount of sales
Other Considerations
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Diseases and rotation
Moving hoop houses
Drainage around tunnels
Simple Hoophouse
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Simple to Build
Frame of plastic or
metal pipe
Anchored by ground
posts
Open ends
Ventilation important
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Doors, sidewalls other
vents
Classic A-Frame
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Very easy construction
Steep roof sheds snow
Limited space (no room
for benches)
Growing space for tall
plants
Ventilation important
Can have second layer
of plastic on inside
Gothic Arch
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Can be portable or
anchored to foundation
Curved walls shed snow
Inexpensive
Lets in lots of light
Modified A-Frame
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Steep roof for shedding
snow
Sits on frame of 4x4 posts +
insulation
More headroom
Room for benches – storage
underneath
Roof Vents
Can use triple wall plastic
panels for more insulation
Sun - Pit
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Foundation sunk below
ground with concrete
block walls
More expensive initially
Recoup costs from
heating savings
Need good drainage
Accessibility concerns
Higher initial costs
Barn Style
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Lots of light – good
headroom
Solid sidewalls
Use plastic panels or
two layers of plastic
With foundation, greater
wind resistance
Attractive design
Slant-Sided Barn Style
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Sheds heavy snow
Wind resistance
Simple construction
Allows room for
benches
Can use double plastic
with squirrel cage fan
Attached Lean-To
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Strong, easy to
construct
Energy savings
Can attach to house wall
with existing door
Need good ventilation
Attached Angled-Wall
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Effective with cold
sunny winters and hot
summers
Wall angled to face low
winter sun
Roof is covered and
insulated against
summer heat
Attached Solar
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Connected to house
with sliding glass doors
Helps heating house in
winter
Summer Cooling from
House
Rigid acrylic or
polyethylene panels
Kit Greenhouses
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Easy to construct
Easily built in 1-2 days
Limited in size
Can be costly
Resources
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www.mielkesfarm.net/hightunnels.htm
http://plasticulture.cas.psu.edu/