1. Succession Planting
for
Continuous Vegetable Harvests
Plan for continuous supplies of popular summer crops,
such as beans, squash, cucumbers and sweet corn; cold-
weather hoophouse greens and year-round lettuce.
©Pam Dawling 2015
author of Sustainable Market Farming
www.sustainablemarketfarming.com
www.facebook.com/SustainableMarketFarming

2. Avoid gluts and shortages
Use your land and time to provide seamless
harvests of summer crops like beans, squash,
cucumbers and sweet corn; cold-weather
hoophouse greens and year-round lettuce.
Photo credits Kathryn Simmons. Cucumber Generally. Lettuce Freckles.

3. Our Story
We garden 3.5 acres of land,
producing vegetables and
berries for 100 people all
year at Twin Oaks Community.
We have a mixed garden
system:
• 60 permanent raised beds,
each 4' × 90' (1.2 × 27.4 m),
• 10 plots of 9,000–10,600 ft2
(836–985 m2), in three
areas of “flat” garden.

5. Find the
space:
Measure
and map
East Garden
227’ x 265’
(Includes
asparagus in half
of one plot)
Plots are 9,275-
10,600 ft2

6. Fit in the
major crops
and use the
leftover
spaces for
summer
succession
crops

8. Fitting in summer succession crops
After locating the major
crops (including sweet corn),
following our rotation plan,
we look for any extra space
in the plots, to fit in the
minor crops:
succession plantings of
beans, summer squash and
zucchini, cucumbers,
edamame and cantaloupes.
Green bean flowers, Photo Kathryn Simmons

9. Summer
Succession
Crops Planning
Chart
• We list the spare
spaces in the plots
(in order of
availability) on the
left
• and the crops we
hope to plant (in
date order) on the
right.

10. Succession
Crops Planning
Chart
 We pencil in arrows,
fitting the succession
crops into the spaces
available.
 At the beginning and
end of the season, and
in mid-season when
space in the main plots
is tight, we also look
for spaces in our raised
beds.

11. Scheduling continuous harvests
 Many vegetable crops can be
planted several times during
the season, to provide a
continuous supply. Don’t stop
too soon!
 Typically, plants mature faster
in warmer weather.
 So, to get harvests starting an
equal number of days apart,
shorten the interval between
one sowing date and the next
as the season progresses.
 Keep records and use
information from other growers
in your area to fine-tune
planting dates.
CREDIT: Kathryn Simmons.

12. Several approaches to succession crop
scheduling – which suits you?
1. Rough plan: “every two
weeks”
2. “No paperwork” methods
3. Sow several varieties on
the same day
4. Plan first and last sowings,
guess the rest
5. Plan a sequence of
sowings to provide an
even supply, using graphs
6. Use Accumulated Growing
Degree Days data
Squash drawing by Jessie Doyle

13. Rough Plan:
Every 2 weeks for beans
and corn,
Every 3 weeks for squash
and cucumbers and
edamame
Every 4 weeks for carrots
2 or 3 plantings of
muskmelons
(cantaloupes) at least a
month apart.
CREDIT: Kathryn Simmons.

14. Spring and fall crops: carrots, beets
• We start sowing carrots mid–late February
• We sow every 4 weeks in March, April, May
• If needed, we sow once each in June and July
• We make a huge fall planting in early August.
• We don’t do succession plantings for fall carrots, just one big
one, because we are growing bulk carrots to store for use all
winter and don’t need multiple harvest dates.
With fall crops, even a
difference of 2 days in sowing
dates can make a difference
of 2-3 weeks in harvest date,
because plants grow slower
as days get shorter and
cooler.

15. “No Paperwork” methods
 Sow another planting of
sweet corn when the
previous one is 1”–2"
tall
 Sow more lettuce when
the previous sowing
germinates
 Sow more beans when
the young plants start
to straighten up from
their hooked stage

16. Sow several varieties with differing days-to-
maturity on the same day.

17. Determine your first spring planting date
Most growers are
probably adept at planting
as soon as possible in the
spring.
Don’t plant too early!
Keeping old cucumber
transplants on hold
through cold early spring
weather is just not
worthwhile.
Spacemaster bush cucumber in the
hoophouse
CREDIT: Kathryn Simmons.

18. Last
worthwhile
planting
date
Figure out the last
date for planting
each crop that gives
it a reasonable
chance of success.
Virginia Co-operative
Extension Service
Fall Planting Guide
http://pubs.ext.vt.ed
u/426/426-334/426-
334.html
WRONG CHART!!

19. Formula for frost-tender crops
Count back from the expected first frost
date, adding:
• the number of days from seeding to
harvest,
• the average length of the harvest
period,
• 14 days to allow for the slowing rate of
growth in the fall, and
• 14 days to allow for an early frost
(unless you have rowcover - there is
often a spell of warmer weather after
the first frosts, and you can effectively
push back your first frost date.)
Zephyr Summer Squash
CREDIT: Kathryn Simmons.

20. Example: Yellow Squash
• number of days from seeding to harvest 50
• average length of the harvest period 21
• 14 days to allow for the slowing rate of growth in the fall 14
• 14 days to allow for an early frost (but we have rowcover) 0
days before the first frost = total of these = 85
last date for sowing, with October 14 first frost date = July 21
But using rowcover to throw over the last planting during cold spells, the growing season is
effectively 2 weeks longer, and we sow our last planting of squash on Aug 5.
We sow our last beans 8/3,
cucumbers 8/5.
We sow our last edamame July 14.
We sow our last sweet corn
July16 (90 days before our
average first frost) and we
harvest from around Sept 22.
Credit Brittany Lewis

21. Making a close-fit plan
Collect three pieces of
information for each
sowing of each crop:
• Sowing date
• Date of first harvest
• Date of last worthwhile
harvest of that sowing

22. Veg Finder
Example:
Squash
#3 WEST Plot J
Plant 6/23 120’
Planted…..
Harvesting…..
Finished…..
BEANS CUKES SQUASH CORN CARROTS EDAMAME
#1 29W, 29E
Plant 4/16 180' dbl
Planted
Harvesting
Finished
#1 BED 13W
Plant 4/20 90'
Planted
Harvesting
Finished
#1 BED 23W
Plant 4/20 90'
Planted
Harvesting
Finished
#1 EAST Plot G 4x265’
Plant 4/26+4/29 1060' Bod
Planted
Harvesting
Finished
#1 BED 9E
Plant 2/14 Danvers
Planted
Harvesting
Finished
#1 BED 21W
Plant 4/26 90’
Planted
Harvesting
Finished
#2 EAST Plot G
Plant 5/14 176’ dbl
Planted
Harvesting
Finished
#2 EAST Plot I
Plant 5/24 180’
slice 90' + pickle 90'
Planted
Harvesting
Finished
#2 EAST Plot I
Plant 5/24 88’
Planted
Harvesting
Finished
#2 EAST Plot G 4x265'
Plant 5/21 1060' Bod/KK/SQ
Planted
Harvesting
Finished
#2 BED 25E
Plant 2/28 Danvers
Planted
Harvesting
Finished
#2 EAST Plot G No-soak
Plant 5/18 88’ dbl
Planted
Harvesting
Finished
#3 WEST Plot J
Plant 6/7 240’ dbl
Planted
Harvesting
Finished
#3 WEST Plot J
Plant 6/23 120’
Planted
Harvesting
Finished
#3 WEST Plot J
Plant 6/23 120’
Planted
Harvesting
Finished
#3 WEST Plot A north 4 x 180'
6/6 1080' Sug Pearl /KK/SQ
Planted
Harvesting
Finished
#3 BED 12W
Plant 3/13 Danvers
Planted
Harvesting
Finished
#3 EAST Plot I
Plant 6/7 60’ dbl
Planted
Harvesting
Finished
#4 EAST Plot K
Plant 6/29 175' dbl
(5x35’)
Planted
Harvesting
Finished
#4 CENT Plot D
Plant 7/15 240'
slice 120' +pickle 120'
Planted
Harvesting
Finished
#4 EAST Plot K
Plant 7/15 105’
(3x35’)
Planted
Harvesting
Finished
#4 WEST Plot A 6 x 180'
6/19 1080' Bod/KK/SQ
Planted
Harvesting
Finished
#4 BED 12E
Plant 3/27 Danvers
Planted
Harvesting
Finished
#4 CENTRAL Plot D
Plant 6/26 60’ dbl
Planted
Harvesting
Finished
#5 25E 22W
Plant 7/19 180’ dbl
(2x90’)
Planted
Harvesting
Finished
#5 BED 15E
Plant 8/5 90' slicers
Planted
Harvesting
Finished
#5 BED 13E
Plant 8/5 90’
Planted
Harvesting
Finished
#5 WEST Plot A 6 x 180'
Plant 7/2 1080' Bod/KK/SQ
Planted
Harvesting
Finished
#5 BED 19W
Plant 4/10 Danvers
Planted
Harvesting
Finished
#5 EAST Plot K
Plant 7/14. 70’ (2x35’)dbl
Planted
Harvesting
Finished
#6 BEDS 9W, 9E
Plant 8/3 180’ dbl
Planted
Harvesting
Finished
#6 CENTRAL Plot D 7 x 200'
Plant 7/16 1400' Bod/KK/SQ
Planted
Harvesting
Finished
#6 BED 17W
Plant 5/14 Danvers
Planted
Harvesting
Finished
#8 BED 1 CARROTS#8 BED 30W
Only if needed
Plant 7/8 Danvers
Planted
Harvesting
Finished
#7 Not this year, perhaps never
again
#7 BED 27E
Only if needed
Plant 6/11 Danvers
Planted
Harvesting
Finished
#8 BED CARROTS #9
Overwinter Raised Beds
Plant 7/28 Danvers
Planted
Harvesting
Finished

23. Gather sowing
and harvest
start dates
Sowing
Date
Harvest
Start
4/18 6/1
4/21 5/19
4/23 5/25
5/14 6/3
5/15 6/21
5/20 7/5
5/25 7/4
5/29 7/7
6/12 7/20
6/15 7/20
6/30 8/2
7/1 8/8
7/2 8/11
7/4 8/8
7/5 8/10
7/14 8/14
7/18 8/17
7/19 8/28
8/3 9/9
8/4 9/5
8/5 9/15
8/7 10/2
8/9 9/25
8/12 10/5
For each crop,
gather several
years’ worth of
planting and
harvesting
records in two
columns (this
example is
squash).

24. Make a graph -
Five steps
1. Plot a graph for each crop,
with sowing date along the
horizontal (x) axis and harvest
start date along the vertical
(y) axis. Mark in all your data.
2. Mark the first possible sowing
date and find the harvest
start date for that.
3. Decide the last worthwhile
harvest start date, mark that.
4. Then divide the harvest
period into a whole number
of segments, according to
how often you want a new
patch.
5. Determine the sowing dates
needed to match your chosen
harvest start dates Next we’ll take one step at a time

25. Step 1: Plot a graph
X axis = Sowing Date, across the bottom
11-May
31-May
20-Jun
10-Jul
30-Jul
19-Aug
8-Sep
28-Sep
18-Oct
1-Apr 21-Apr 11-May 31-May 20-Jun 10-Jul 30-Jul 19-Aug
Y axis = Harvest Start Date

26. Step 2: Mark
the first
possible sowing
date, find the
harvest start
date for that
 Draw a line up from
your first possible
sowing date on the x
axis to the graph
line.
 Draw a horizontal
line from the point
on the graph line to
the y axis.
 This is your first
harvest date. Ours is
around May 19.
11-May
31-May
20-Jun
10-Jul
30-Jul
19-Aug
8-Sep
28-Sep
18-Oct
1-Apr 21-Apr11-May31-May 20-Jun 10-Jul 30-Jul 19-Aug
Y axis = Harvest Start Date

27. Step 3: Set
your last
worthwhile
harvest date
• Decide your last
worthwhile harvest start
date of the year
• Draw a line across from
this date on the y
(harvest) axis to the
graph line
• Draw a vertical line from
this point on the graph
line to the x axis to
show when you need to
sow
• Our Aug 7 sowing gave
an Oct 2 harvest start.
Too late!
• Now we sow Aug 5 and
harvest from Sept 24
11-May
31-May
20-Jun
10-Jul
30-Jul
19-Aug
8-Sep
28-Sep
18-Oct
1-Apr 21-Apr11-May31-May20-Jun 10-Jul 30-Jul 19-Aug
Y axis = Harvest Start Date

28. Step 4: Divide the harvest period into a whole
number of segments, according to how often
you want a new patch
 Count the days from first harvest of the first sowing to first harvest of the
last sowing: May 19 - Sept 24 is 128 days of squash! (Plus the 30 days from
the harvest start of the last sowing to the end = 158 days of squash!!)
 Decide roughly how often you want a new patch coming into production
 Divide the harvest period into a whole number of intervals. If we want
fresh squash every 32 days, we’ll need 4 equal intervals between plantings
(32 x 4 = 128).
 Four intervals means 5 plantings. (P-I-P-I-P-I-P-I-P)
 The harvest start dates will be
May 19, June 20, July 22, Aug 23 and Sept 24.
 Use the graph to get the planting dates needed.
April 21, May 17, June 21, July 16, and Aug 5.
 Sowing intervals are 26, 25, 25, 20 days – a bit shorter later in the season.

29. Step 5: Determine the sowing
dates needed to match your
chosen harvest start dates
• Draw a horizontal line from one harvest start
date to the graph line
• Then drop a vertical line down to the
horizontal axis
• Read the date on the horizontal axis at this
point
• Repeat for each harvest start date
• Write these planting dates on your schedule

30. Squash Succession Crops
Sowing date Harvest start
Apr 18 Jun 1
Apr 21 May 19
Apr 23 May 25
May 14 Jun 3
May 15 Jun 21
May 20 Jul 5
May 25 Jul 4
May 29 Jul 7
Jun 12 Jul 20
Jun 15 Jul 20
Jun 30 Aug 2
Jul 1 Aug 8
Jul 2 Aug 11
Jul 4 Aug 8
Jul 5 Aug 10
Jul 14 Aug 14
Jul 18 Aug 17
Jul 19 Aug 28
Aug 3 Sep 9
Aug 4 Sep 5
Aug 5 Sep 15
Aug 7 Oct 2
Aug 9 Sep 25
Aug 12 Oct 5
Apr 27
May 17
Jun 6
Jun 26
Jul 16
Aug 5
Aug 25
Sep 14
Oct 4
Oct 24
Apr12
Apr22
May2
May12
May22
Jun1
Jun11
Jun21
Jul1
Jul11
Jul21
Jul31
Aug10
HarvestStart
Sowing Date
Squash Succession Crops
With several years
of data you might
get an very
uneven line.
Squash Succession Crops Graph with multiple
years of data

31. Smoothing the graph line
The line of the graph is often uneven, due to
differences in weather from year to year, and to
growing varieties with differing maturity dates.
Practice with a pencil, drawing a line in the air
just above the graph.
When you’re fairly confidant, draw a smooth line,
trying to hit most of points, leaving equal
numbers of them above and below the graph
line.

32. Another Example: Sweet Corn
• Using our graph of corn sowing and harvest dates (on
the next slide) I estimate that April 26, May 19, June 6,
June 24, July 7, and July 16 would be good dates for 6
plantings to provide fresh eating every 15 days.
• The planting intervals are 23, 18, 18, 13 and 9 days.
• The intervals get noticeably shorter as the season goes
on.

34. Reminder of the main goals of planned
succession planting:
Continuous supplies of popular summer crops, such as
beans, squash, cucumbers and sweet corn; cold-weather
hoophouse greens and year-round lettuce.
Avoid gluts and shortages.
Cucumber Generally. Photo credit Kathryn Simmons.

35. Extra benefits from planned
succession planting:
Save space and work
• We used to do 6 plantings of cucumbers.
• The intervals between sowings were 50, 30, 20, 16, and 17 days.
• By using the graphs, we have been able to go down to 5 plantings, at
intervals of 52, 25, 25 and 20 days. The sowing intervals decrease as the
season warms up, as it takes fewer days for plants to mature. The first
planting uses transplants and is very slow to mature — probably we
could just start later still and lose nothing.
• By moving the second planting 10 days later than it used to be, we are
able to direct sow rather than transplant, which saves us time.
• This revised schedule saves us from dumping cucumbers on our
neighbors’ porches!

36. Cucumber Succession Crops
Sowing Date Harvest Start 0.880152 4622.504
4/23 6/18
4/25 6/3 38832 38900.58 38871
5/9 6/18
5/14 7/3
5/15 6/22
5/27 7/15 #REF! #REF!
6/12 7/29
6/21 8/9
6/25 7/27
6/28 8/1
6/30 7/23
7/2 8/16
7/4 8/15
7/5 8/20
7/7 8/21
7/14 8/28
7/18 9/8
7/19 9/10
8/3 9/21
8/6 9/29
8/11 9/25
8/12 10/5
5/19
5/29
6/8
6/18
6/28
7/8
7/18
7/28
8/7
8/17
8/27
9/6
9/16
9/26
10/6
10/16
4/13
4/23
5/3
5/13
5/23
6/2
6/12
6/22
7/2
7/12
7/22
8/1
8/11
HarvestStartDate
Sowing Date
Cucumber Succession Crops

37. Benefits of succession planting:
Avoid chancy sowings: sweet corn
• We used to make 7 sweet corn
plantings: April 26, May 17, June 2, June
16, June 30, July 14 and July 28. The
intervals were 21, 15, and then 14 days.
• We eliminated the late (and sometimes
unproductive) 7th planting and
increased the size of the 6th, sowing our
usual range of 3 varieties.
• Using the graph of our corn sowing and
harvest dates, we switched to 6
plantings with intervals of 23, 18, 18, 13
and 9 days.
Silver Queen Sweet Corn. Credit Kathryn Simmons

38. Factors in
succession planting:
Keep it simple
• Cucumbers also take a little longer to mature than
squash.
• These two features would suggest making more
plantings of cucumbers than of squash,
• BUT. . . after looking at the graphs, we decided to plant
both on the same set of dates, for simplicity.
• If we could be satisfied with a new patch coming on-
stream every 36 days, we could sow only four times.
• Our squash plantings stay
productive for around 40
days, but cucumbers
sometimes only last 35 days.

39. Other factors affecting
planting frequency:
Mexican bean beetles
Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org
• Mexican bean beetles used to
destroy our beans.
• We needed 7 plantings at 15-day
intervals.
• After 2 weeks of harvesting a
planting, we did “Root Checks.”
• Now we buy the parasitic pedio
wasp, and sow 6 times, not 7.
• These sowing intervals are 28, 28,
22, 20 and 15 days.
• We also get more beans than
previously, and they’re prettier.
• Bean photo credit Kathryn Simmons

40. Bean Beetle Parasite
(Pediobius foveolatus)
• These tiny wasps do not overwinter, so buy them each year
unless you don’t get enough MBB to worry about.
• Wasps are shipped to you as adults or as parasitized
Mexican bean beetle larvae, called mummies. The adults
emerge from the mummies, and the females lay eggs in
your MBB larvae.
• Timing is critical: order as soon as you see larvae.
• Release 20 mummies = 400-500 wasps for every 1000 sq. ft.
of beans (40 units/acre). 2013 prices $60/1000 adults,
$30/20 mummies. Plus UPS Next Day Saver, about $20.
• NJ Department of Agriculture Beneficial Insect Rearing
Laboratory contact: Tom Dorsey at (609) 530-4192. See
http://www.state.nj.us/agriculture/divisions/pi/prog/benef
icialinsect.html

41. Bean Succession Crops
Sowing
Date
Harvest
Start
4/16 6/13
4/18 6/20
4/20 6/16
4/21 6/14
5/2 6/23
5/7 7/2
5/11 7/8
5/12 7/5
5/13 7/1
5/14 6/30
5/16 7/1
5/17 7/3
5/22 7/16
6/5 7/30
6/8 8/2
6/10 8/3
6/13 8/1
6/24 8/9
6/29 8/24
6/30 8/15
7/8 8/21
7/14 8/28
7/15 9/2
7/19 9/3
7/20 9/1
7/22 9/6
7/25 9/11
8/3 9/18
8/4 9/26
8/6 9/30
8/7 9/20
40700
40710
40720
40730
40740
40750
40760
40770
40780
40790
40800
40810
40820
40830
40645
40655
40665
40675
40685
40695
40705
40715
40725
40735
40745
40755
40765
40775
HarvestStartDate
Sowing Date
Bean Succession Crops
Bean Succession Crops graph with several years’ data

42. Winter succession crops in the
hoophouse
To maintain continuous supplies of salad and cooking
greens, as well as radishes and small turnips, we plan
several winter successions of hoophouse crops.

43. Planning winter succession crops
• Hoophouse space is so valuable,
make best use
• Rate of growth is faster inside than
out
• Plants tolerate colder conditions in
a hoophouse than they could
outdoors
• Double plastic hoophouse in zone
7, with extra thick rowcover for an
inner tunnel, salad greens can
survive when it’s -12F (-24C)
outside
• Without the inner rowcover, they
survive when it’s 14F (-10C)
outside.
Photo of tatsoi by Wren Vile

44. Gather information as you go
• Our hoophouse planting schedule includes a column for
Harvest Start date and Harvest Finish date.
• In tiny print we the dates from recent years
• We leave space to write in results from the current year

45. Factors to consider
• Seeds may take much
longer to germinate in
cold weather
• “Days to maturity”
number in the catalog
refers to spring - add 14
days or more
• If the catalog is from a
different bioregion,
beware!
Photo of Chinese cabbage by Southern Exposure
Seed Exchange

46. Hoophouse
Succession
Planting
• 2 sowings of chard,
mizuna, scallions,
tatsoi, yukina
savoy
• 3 sowings of
turnips, bulb
onions
• 4 sowings of
lettuce mix
• 5 sowings of
spinach and radish

47. Back to the graphs
• Using succession crop
graphs follows the same
process as for outdoor
summer crops
• Keep good records and
eliminate sowings that are
too late to give a harvest –
some crops bolt in January
(Tokyp bekana and Maruba
Santoh), some in February
(tatsoi)
Cherry Belle radishes. Photo by
Southern Exposure Seed Exchange

48. Radish Succession Crops Graph

49. “Filler Greens”
• As well as scheduled
plantings, sow a few
short rows of lettuce,
spinach, Asian greens to
transplant and fill gaps
as soon as they occur
Large transplants of filler greens.
Photo by Ethan Hirsh

50. Follow-on Winter Hoophouse Crops
• Some people use the term “Succession Planting” to refer to a
succession of different crops occupying a space.
• We follow our first radishes with our second scallions on 11/17
• Our first baby brassica salad mix with our fifth radishes on 12/23
• Some of our first spinach with our second baby lettuce mix on 12/31
• Our first tatsoi with our fourth spinach on 1/15
• Our Tokyo bekana on 1/16 with spinach for transplanting outdoors
• Our pak choy and Chinese cabbage on 1/24 with kale for planting
outdoors
• Our second radishes with our second baby brassica salad mix on 2/1

51. Year-round lettuce part 1
Photo Credits Kathryn Simmons
The short version is that
we sow
• twice in January,
• twice in February,
• every 10 days in March,
• every 9 days in April,
• every 8 days in May,
• every 6-7 days in June
and July,

52. Year-round lettuce part 2
Photo: Cold-hardy (not heat-tolerant) Tango lettuce. Credit Kathryn Simmons
• every 5 days in early August,
• moving to every 3 days in
late August,
• and every other day until
Sept 21.
• After that we ease back to
every 3 days until the end of
September.
• Those last plants will feed
us right through the winter.
Hot weather lettuce sowing
 Lettuce likes 40°F–80°F (4°C–27°C).
 Optimum 75°F (24°C) (germinates in only
2 days).
 Max germination temperature is 85°F
(29°C).
 Sow late afternoon or at nightfall - better
emergence than morning sowings.

53. Lettuce Succession Crops
Sowing Date Harvest Start 1/0 1/13
1/5 4/12
1/15 4/15
1/25 4/17
2/5 4/20
2/15 4/26
2/25 5/1
3/5 5/5
3/15 5/11
3/25 5/18
4/5 5/25
4/15 6/4
4/20 6/11
5/6 6/23
5/17 7/1
5/25 7/7
6/1 7/13
6/8 7/20
6/15 7/31
6/22 8/6
6/29 8/12
7/6 8/18
7/13 8/24
7/20 8/30
7/27 9/5
8/3 9/11
8/5 9/13
8/15 9/27
8/25 10/12
9/5 11/10
9/15 12/16 9/15 9/20 12/16
9/25 1/13 #REF! #REF!
10/5 2/2
10/15 2/15
10/25 2/25
11/5 2/25
11/15 3/18
11/25 3/28
12/5 4/4
12/15 4/6
12/25 4/9
Dates from Coleman
Italic dates approximate, from Twin Oaks
4/13
4/23
5/3
5/13
5/23
6/2
6/12
6/22
7/2
7/12
7/22
8/1
8/11
8/21
8/31
9/10
9/20
9/30
10/10
10/20
10/30
11/9
11/19
11/29
12/9
12/19
12/29
1/8
1/18
1/28
2/7
2/17
2/27
3/9
3/19
3/29
4/8
4/18
1/13
1/23
2/2
2/12
2/22
3/4
3/14
3/24
4/3
4/13
4/23
5/3
5/13
5/23
6/2
6/12
6/22
7/2
7/12
7/22
8/1
8/11
8/21
8/31
9/10
9/20
9/30
10/10
10/20
10/30
11/9
11/19
11/29
12/9
12/19
12/29
HarvestStartDate
Sowing Date
Lettuce Succession Crops

54. Growing Degree Days
 A measure of heat accumulation
 can indicate when it’s warm enough to plant tender crops,
 or when they might be ready to harvest.
 GDDs can also be used to plan dates for succession sowings.
 GDDs reflect actual conditions, rather than simply the calendar, a
method which will not work well now climate change has taken
hold.
 For most purposes a base temperature of 50°F (10°C) is used –
roughly the temperature at which most plant growth changes start
to take place. Each day when the temperature rises above the
threshold, growing-degrees accumulate.

55. Growing Degree Days
 Average the maximum and minimum temperatures for
the 24 hour period, and subtract the base temperature.
Add each day’s figure to the total for the year to date.
This is the GDD figure.
 Wikipedia has a good explanation at
www.en.wikipedia.org/wiki/Growing-degree_day
 www.farmprogress.com has a free mobile phone app!
 Using GDDs to plan for succession sowings of sweet corn
http://www.hort.uconn.edu/ipm/veg/htms/scpltsched.h
tm
 Using Heat Units to Schedule Vegetable Plantings,
Predict Harvest Dates and Manage Crops
http://smallfarms.oregonstate.edu/sfn/f11degreedays

56. Resources 1
 ATTRA Market Farming: A Start-up Guide, https://attra.ncat.org/attra-
pub/summaries/summary.php?pub=18
 ATTRA Scheduling Vegetable Plantings for a Continuous Harvest,
www.attra.ncat.org/attra-pub/summaries/summary.php?pub=20
 ATTRA Intercropping Principles and Production Practices (mostly field
crops, but the same principles apply to vegetable crops),
www.attra.ncat.org/attra-pub/summaries/summary.php?pub=105
 ATTRA Season Extension Techniques for Market Farmers,
https://attra.ncat.org/attra-pub/viewhtml.php?id=366
 SARE at www.sare.org -A searchable database of research findings
 SARE’s Season Extension Topic Room
 http://www.extension.org/organic_production The organic agriculture
community with eXtension. Publications, webinars, videos, trainings and
support. An expanding, accessible source of reliable information.

57. Resources 2
 Virginia Co-operative Extension Service Fall Planting Guide
http://pubs.ext.vt.edu/426/426-334/426-334.html. Wrong
chart currently!
 Growing Small Farms:
http://growingsmallfarms.ces.ncsu.edu/ Debbie Roos keeps
this site up to the minute. Click on Farmer Resources
 www.johnnyseeds.com. Winter growing guide
 www.motherofahubbard.com Winter Vegetable Gardening
 www.averagepersongardening.com info on winter gardening
 Penn State Extension High Tunnels site
www.extension.psu.edu/plants/plasticulture/crop-
information
 www.HighTunnels.org Information for growers section.

58. Resources 3 - books
 The Complete Know and Grow Vegetables, J. K. A. Bleasdale, P. J. Salter et al.
 Knott’s Handbook for Vegetable Growers, Donald N. Maynard and George J.
Hochmuth. The 2012 edition is free online from Missouri Extension
 The New Seed Starter’s Handbook, Nancy Bubel, 1988, Rodale Books
 The Organic Farmer’s Business Handbook, Richard Wiswall, Chelsea Green
 Sustainable Vegetable Production from Start-up to Market, Vern Grubinger
 The New Organic Grower, Eliot Coleman, 1995, Chelsea Green
 The Winter Harvest Handbook, Eliot Coleman
 Extending the Season: Six Strategies for Improving Cash Flow Year-Round on
the Market Farm, a free e-book download for online subscribers to Growing
for Market magazine
 The Hoophouse Handbook, 2nd edition, Lynn Byczynski
 Nature and Properties of Soils, fourteenth edition, Nyle Brady and Ray Weil
 Garden Insects of North America, Whitney Cranshaw
 The Harvest Gardener, Susan McClure

59. Succession Planting for
Continuous Vegetable Harvests
Plan for continuous supplies of popular summer crops,
such as beans, squash, cucumbers and sweet corn;
cold-weather hoophouse greens and year-round
lettuce.
©Pam Dawling 2015
author of Sustainable Market Farming
www.sustainablemarketfarming.com
www.facebook.com/SustainableMarketFarming