CROPTIME
ONLINE VEGETABLE SCHEDULING
HTTP://SMALLFARMS.OREGONSTATE.EDU/CROPTIME
Nick Andrews & Heidi Noordijk
OSU Small Farms Extension
North Willamette Research & Extension Center
503-913-9410
Collaborators
Len Coop
Jim Myers
Ed Peachey
Dan Sullivan
Aaron Heinrich
Heather Stoven
Amy Garrett
Jeremy Cowan (WSU)
René A. F. de Réaumur
(1683-1757)
• Used daily mean temperatures to
predict plant development in mid
18th Century
• The importance of threshold
temperatures was recognized by
mid-20th Century (i.e. Arnold, 1959)
• Threshold temperatures are low or
high temperatures that limit
development and growth
Simple average degree-days
If high = 68°F & low = 45°F &
Base temp for sweet corn = 50°F, then
(68+45) / 2 = 56.5
56.5 – 50 = 6.5 degree-days
Degree-days and sine curves
Cutoff methods
Horizontal Intermediate Vertical No cutoff
Using degree-days
David Brown, Mustard Seed Farm “I have used degree days for
over 20 years to schedule
successive plantings of
vegetables.
I have made some educated
guesses… (but) having more
information, based on some
research, would be helpful in
refining my schedules and
maybe even using the
information for more crops.”
• Snap beans (3)
• Tomato (5)
• Summer squash (5)
• Cucumber (4)
• Sweet pepper (7)
• Winter squash (4)
• Sweet corn (6)
Fruiting Crops (34)
• Carrot (3)
• Parsnip (4)
Root Crops (7)
Brassicas (15) • Broccoli (4)
• Cabbage (6)
• Cauliflower (3)
• Kale (2)
Leafy crops (7)
• Spinach (4)
• Lettuce (3)
Priority crops ID’d by
growers
Goal > 50 crop models by Mar 2017
Transplant
Growth stages - Broccoli
Cupping
Head Initiation
Mature
Early Flowering
Using Croptime 1. Search for Croptime
http://smallfarms.oregonstate.edu/croptime
Select weather
station
(Google maps)
Enter
planting
dates
Hit CALC/RUN
Select
crop &
variety
Date Temp/Precip DD Day
length
Cum
DD Crop events
Scroll right for other
planting dates
Apr 1 = 88 DTM
May 1 = 74 DTM
Jun 1 = 68 DTM
Jul 1 = 68 DTM
2nd planting 3rd planting 4th planting
Different seed catalogs
estimate 63-94 DTM
Degree-day models use local
temperature data, forecasts and
historical averages or forecasts to
predict harvest within a few days
• 66-103 DTM
• 20-32 days difference within a season
• 0-14 days difference at same planting date in
different seasons
• Average 7 days slower development in cooler years
(2011-2012) than in warmer years (2013-2015)
Forecasts
“The dramatically different weather we have had
this spring and last makes it hard to know what to
expect.” Tanya Murray, Sauvie Island Organics
Len Coop
• Separate grant to convert long-term
weather model data to degree-days
• This will be an improvement over
current 30-year averages
Thermal time to maturity (2013-14 data)
Transplanted
broccoli
40/70F, SSHCO
50% head
initiation
First harvest Early
flowering
Accuracy
(± days)
Arcadia (TP) 1278 1702 1984 2.0
Green Magic (TP) 1137 1623 1828 5.0
Transplanted sweet
pepper
52/--F, SSHCO
Fruit set First green
harvest
First ripe
harvest
Accuracy
(± days)
Stocky Red Roaster 553 1221 1680 2.0
Gatherer’s Gold 501 1237 1694 3.0
~3 days diff.
between
varieties
>1 day diff.
±15 days in
catalogs
Cucumber
50/80F, SSICO
First flower First harvest Accuracy
(± days)
Cobra (DS) 561 870 2.88
Marketmore (TP) 358 682 4.0
Marketmore (DS) 654 952 2.5
Direct seeded
sweet corn
50/86, corn DD
5 true
leaves
100% silk Fresh
market
harvest
Processed
market
harvest
Accuracy
(± days)
Kokanee 306 1112 1522 1635 2.6
Luscious 277 1004 1134 -- 3.75
Thermal time to maturity (2013-14 data)
~11days diff.
~16 days diff.
1. Summarize the GDD requirements of selected weedy species from literature.
2.Use degree day models to predict when weeds must be removed to prevent seed production
3.Use interpretive skills of participating growers to validate and develop DD models
GDD Models for Weeds
GDD Emergence Models
WeedCast, Forcella
May 1 planting date in western Oregon
Background
Downy Brome seed production
Dan Ball, Pendleton OSU
Hairy nightshade case study 2003 and 2004
0
50
100
150
200
250
23-Apr 7-May 21-May 4-Jun 18-Jun
Berry no/plant
Snap bean planting date
0
2
3
Weeks of weed removal after planting
Hairy nightshade case study
Croptime Weed models • What will the weed stage be at harvest?
• Do I need to send in a crew to hand weed
before harvest to prevent weed seed rain?
• $300 per acre
• Turn in weeds after harvest
Grower estimates
• Do you think the seeds are viable?
• Grower #1 thought they were close to
viable
• Grower #2 thought that no seeds were
viable
• Lab results – 53% viable
Weed models chosen by producers
• Hairy Nightshade
• Lambs Quarter
• Pigweed
• Crabgrass
Data collection
• Cotyledon stage
• Monitored every one to two weeks through flowering
• Monitored 1x per week from flowering to early seed
• Seed collected 2x per week from early seed to seed
rain
Pigweed model development
• Cotyledon to first viable seed
• 2015 data
• Upper threshold
10
11
12
13
14
15
16
17
18
40 45 50 55 60 65
CV
(%
)
Tlow (F)
Pigweed First viable seed
Hairy nightshade time to maturity
Hairy Nightshade
Cotyledon to
First Flower
(DD)
Cotyledon to
First Flower
(Days)
First Flower
to
First viable seed
(DD)
First Flower
to
First viable seed
(Days)
778 34 1085 36
Challenges
• Identifying weed seedling
• Uncertain if degree-days will be more accurate than
locally determined days
Upcoming Croptime Workshops
Thur Feb 11 (10-2:30) at NWREC
Sat Feb 20 OSU Small Farms Conference
