Succession Planting for Continuous Vegetable Harvests How to plan sowing dates for continuous supplies of popular summer crops, such as beans, squash, cucumbers, edamame and sweet corn; cold-weather hoophouse greens and year round lettuce. Using these planning strategies can help avoid gluts and shortages.

1. Succession Planting
for
Continuous Vegetable Harvests
©Pam Dawling 2019
author of Sustainable Market Farming
and The Year-Round Hoophouse
www.sustainablemarketfarming.com
www.facebook.com/SustainableMarketFarming

2. What’s in this Presentation
• Introductions
• Finding space for succession crops
• Several approaches to scheduling succession crops
• My method - making graphs step by step
• Summer crops
• Year round lettuce
• Winter hoophouse succession crops
• Extra benefits of succession crop
scheduling
• Other factors in crop scheduling
• Resources

3. I live and farm at Twin Oaks Community, in central Virginia.
We’re in zone 7, with an average last frost April 30 and average first frost
October 14. Our goal is to feed our intentional community of 100 people with a
wide variety of organic produce year round. www.twinoaks.org

4. Our Gardens
We garden 3.5 acres of land,
producing vegetables and
berries for 100 people all
year.
We have a mixed garden
system:
• 60 permanent raised beds,
each 4' × 90' (1.2 × 7.4 m),
• 10 plots of 9,000–10,600
ft2 (836–985 m2), in three
areas of “flat” garden (row
crops).

6. This Workshop:
Avoid Gluts and Shortages
Many crops can be planted several times during its season,
to provide a continuous supply. Don’t stop too soon!
Use your land and time to provide seamless harvests of
summer crops; year-round lettuce and cold-weather
hoophouse greens.
Photos Kathryn Simmons. Cucumber Generally. Lettuce Freckles.

7. Examples of Succession Crops:
• Beets, broccoli, cabbage, carrots, collards, kale,
spinach can be grown in spring and again in the fall
in the Southeast.
• Beans, edamame, cucumbers, melons,
squash, sweet corn can be produced
through the frost-free period, if you
sow several times.
• Lettuce can be grown year-round
• Lettuce, spinach, turnips, radishes, scallions, tatsoi
and some other Asian greens can be sown in
succession in a winter hoophouse

8. Spring and Fall Crops Example: Carrots
• 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.

9. East Garden
227’ x 265’
Plots are
9,275-10,600
ft2
Finding Spaces
for Summer
Succession
Crops:
Measure and
Map

10. First Fit in
your Major
Crops
Then use
leftover
spaces for
summer
succession
crops

11. For all the
details, see my
slideshow Crop
Rotations for
Vegetables and
Cover Crops on
SlideShare.net

12. Our Summer Succession Crops
After locating the major
crops (including sweet
corn), following our
rotation plan, we look for
extra spaces in the plots, to
fit in the smaller
succession plantings of
beans, summer squash,
zucchini, cucumbers,
edamame and
cantaloupes.
Green bean flowers, Photo Kathryn Simmons

13. Summer
Succession
Crops Planning
Chart
• On the left we list
the spare spaces
in the plots (in
order of
availability)
• On the right are
the crops we hope
to plant (in date
order).

14. 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.

15. 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

16. Succession Planting for Continuous
Harvests
 As temperatures and day-length
decrease in the fall, the time to
maturity lengthens – a day late
in sowing can lead to a week’s
delay in harvesting.
 As temperatures and day-length
increase after the Winter
Solstice, the time to maturity
shortens.
 To get harvests starting an
equal number of days apart,
vary the interval between one
sowing date and the next
accordingly
Tatsoi. Photo Ethan Hirsh

17. Scheduling Succession Crops
Typically, plants mature
slower in colder weather
and you need longer sowing
intervals,
and shorter intervals
between one sowing date
and the next in warmer
weather, when crops mature
faster.
Keep records and use
information from other
growers in your area to fine-
tune your planting dates.
Use our graph-making
method for best results
Bean bed in June. Photo Pam Dawling

18. Several Approaches to Succession Crop
Scheduling – Which Suits You?
1. Rough plan for summer
crops: “every two weeks”
2. “No paperwork” methods
3. Sow several varieties on
the same day
4. Plan a sequence of
sowings to provide an
even supply, using graphs
5. Use Accumulated
Growing Degree Days
Squash drawing by Jessie Doyle

19. 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.
PHOTO: Kathryn Simmons.

20. “No Paperwork” Methods
Sow another planting
of sweet corn when the
previous one is 1”–2”
2.5 – 5 cm) tall
Sow more lettuce when
the previous sowing
germinates
Sow more beans when
the young plants start
to straighten up from
their hooked stage Lettuce seedlings nudge you to sow more.
Photo Pam Dawling

21. Use varieties with
different days-to-
maturity sown on
the same day.
We do this with
broccoli, lettuce,
sweet corn.
Sow Several Varieties on One Day
Photo Small
Farm Central

22. 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.
• I finally grasped this the
year we transplanted our
first and second cucumber
plantings side by side on the
same date one cold spring.
• The second ones did better
than the first, and were
ready just as soon!
Spacemaster bush cucumber in the
hoophouse
Photo: Kathryn Simmons.

23. Determine the Last Sowing Date 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

24. 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 7/14.
We sow our last sweet corn
7/16
Credit Brittany Lewis

25. Making a Close-fit Plan Using Graphs
To provide an unbroken
regular supply of a
particular crop, make a
graph of
Sowing dates versus
Date of first harvest of
each sowing.
Keep good records and
eliminate sowings that
are too late to give a
harvest

26. Make a Graph - 6 Steps
1. Gather sowing and harvest start and finish dates for
each planting of each crop. Even just one year’s data.
2. Make a graph for each crop: sowing date along the horizontal
(x) axis; harvest start date along the vertical (y) axis. Mark in all
your data. Join with a line. Smooth the line.
3. From your first possible sowing date find the first harvest start
date.
4. Decide the last worthwhile harvest start date, mark that.
5. Use the harvest end dates to see how long a planting lasts
(how often you want a new patch starting). Divide the harvest
period into a whole number of equal segments of that length.
6. Mark in the harvest start dates and see the sowing dates that
match those harvest dates Next we’ll take one step at a time

27. Step 1: Gather
Sowing &
Harvest 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
(Summer squash
example).
For each crop, gather
several years’ worth
of planting and
harvesting records in
two columns.
You can start with
just one year of data.

28. For each sowing of each crop, collect
1. Sowing date
2. Date of first harvest
3. Date of last worthwhile harvest of
that sowing
 Here’s the first part of our data for
winter radishes in the hoophouse.
 Compared to spring and summer
plantings, the results for winter
plantings can look quite wacky, as
plants “sit still” when it’s too cold.
 Spinach, lettuce and kale grow
every time the temperature is 40F
(4.5C) or more.
 Some other crops need warmer
temperatures to make any growth.
Sowing
Date
Harvest
Start
Harvest
End
6-Sep 30-Sep 7-Nov
6-Sep 3-Oct 10-Nov
6-Sep 7-Oct 7-Nov
1-Oct 2-Nov 17-Dec
1-Oct 10-Nov 25-Dec
5-Oct 9-Nov 2-Jan
Winter
Hoophouse
Radishes
Step 1 Gather Sowing & Harvest Dates

29. Summer Squash Step 2. Plot a Graph
X axis = Sowing Date, across the bottom
This example has only one year of data
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

30. Radishes Step 2 Make a Graph
X axis = Sowing Date, across the bottom
• Mark in all your data, and join with a line.
• Graphs can be made by hand or using a spreadsheet program such as
Excel, which calls them charts. This type of graph is called a “scatter
chart.”
9/7/2016
9/27/2016
10/17/2016
11/6/2016
11/26/2016
12/16/2016
1/5/2017
1/25/2017
2/14/2017
3/6/2017
3/26/2017
4/15/2017
8/18/2016 9/7/2016 9/27/201610/17/201611/6/201611/26/201612/16/2016 1/5/2017 1/25/2017 2/14/2017
Harveststartdate
Sowing date
Ser…
Yaxis=HarvestStartDate
Winter
hoophouse
Radishes -
several
years’ data

31. Step 3 From Your First Possible Sowing
Date Find the First Harvest Start Date
Draw a line up from
your first possible
sowing date on the x
axis to the graph
line. 9/7?
Draw a horizontal
line from the point
on the graph line to
the y axis.
This is your first
harvest date. Ours is
around 10/1.
Harvest date varies
according to
temperature.
9/7/2016
9/27/2016
10/17/2016
11/6/2016
11/26/2016
12/16/2016
1/5/2017
1/25/2017
2/14/2017
3/6/2017
3/26/2017
4/15/2017
8/18/2016 9/7/2016 9/27/2016 10/17/2016 11/6/2016 11/26/2016 12/16/2016 1/5/2017 1
Harveststartdate
Sowing date

32. Step 4 Decide Your Last Worthwhile
Harvest Start Date (Radishes)
• Decide your last
worthwhile harvest
start date 3/18?
• Draw a line across
from this date on
the y (harvest) axis
to the graph line
• Draw a line from
this point on the
graph line down to
the x axis to show
when to sow. 1/26?
9/7/2016
9/27/2016
10/17/2016
11/6/2016
11/26/2016
12/16/2016
1/5/2017
1/25/2017
2/14/2017
3/6/2017
3/26/2017
4/15/2017
8/18/20169/7/20169/27/201610/17/201611/6/201611/26/201612/16/20161/5/20171/25/20172/14/2017
Harveststartdate
Sowing date
S…

33. • The line joining the points on the graph is often jagged,
due to differences in weather from year to year, and to
growing varieties with differing maturity dates.
• Smooth the jaggedness by drawing a smooth line
hitting most of your points, with equal numbers of
points above and below it, equally distributed over
time.
• Practice with a pencil, drawing a line in the air just
above the graph.
• When you’re fairly confident, draw a
smooth line.
• With radishes the curve is slight, but
it’s there.
Smoothing the Graph Line

34. Radish Succession Crops Graph
with Smoothed Line

35. With several
years of data
you might get
anvery uneven
line.
Summer Squash Succession
Crops with 15 Years of Data

36.  Count the days from first harvest of the first sowing to the first
harvest of the last sowing: May 19 – Sept 24 = 128
 Use the harvest end dates to see roughly how long a patch of
squash lasts (how often you want a new patch coming on line)
 Divide the harvest period into a whole number of equal
intervals of that length. If we want a new squash patch 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.
Squash Step 5: Divide the Harvest Period
into a Whole Number of Equal Segments

37. Step 5 Divide the Harvest Period into
a Whole Number of Equal Segments
 Count the days from first harvest of the first sowing to the first
harvest of the last sowing:10/1–3/18=30+30+31+31+28+18=168
 Use the harvest end dates to see roughly how long a patch of
radishes lasts (how often you want a new patch coming on line)
 Divide the harvest period into a whole number of equal
intervals of that length. If we want new radishes every 34 days,
we’ll need 5 equal intervals between plantings (34 x 5 = 170).
 Five intervals means 6 plantings. (P-I-P-I-P-I-P-I-P-I-P)
 The harvest start dates will be 10/1, 11/4, 12/8, 1/11, 2/14,3/20
 Draw a horizontal line from each harvest start date to the graph
line – see next slide

38. Radish Succession Crops
Harvest Start Dates

39. Radish Succession Crops
Sowing Dates

40. Radishes Step 6 See the Sowing Dates
that Match Your Harvest Start Dates
 Drop a vertical line down to the horizontal axis from each place
that a horizontal line meets your smoothed curve.
 Read the date on the horizontal axis at this point
 Write these planting dates on your schedule: 9/7, 9/30, 10/28,
11/22, 12/20, 1/27
 Sowing intervals are 23, 28, 25, 28, 38 days – longer in Dec-Jan,
as the rate of growth is so slow.
 If your planting plans exceed the space you’ve got, simply
tweaking to a less frequent new harvest start could free up
space to grow something else.
 Also consider a gap in radish supply, if other crops could
make better use of the space.

41. With several
years of data
you might get
anvery uneven
line.
Summer Squash Succession
Crops with 15 Years of Data

42. Squash Step 6: See the Sowing Dates
that Match your Harvest Start Dates
 For 5 plantings of summer squash, our harvest start dates will
be May 19, June 20, July 22, Aug 23 and Sept 24.
 Sowing dates: April 21, May 17, June 15, July 19, and Aug 5.
 Sowing intervals are 26, 29, 34, 21 days – variable and a bit
shorter later in the season.
 Not sure about this one – maybe squash idles while it’s hot in
late June and early July??

43. Our Radish Succession Dates
1. Radish #1, sown 9/6, harvested 10/5-
11/15.
2. #2, sown 10/1, harvested 11/6-12/25
3. #3, sown 10/30, harvested 12/16-2/7
4. #4, sown 11/29, harvested 2/8-2/25
5. #5, sown 12/23, harvested 2/24-3/16
Our harvest intervals are uneven: 31-40 days.
This fits better with our other crops.
• The data led us to cut back to sowings of 32' (10 m) each.
• Previously we had been sowing longer rows than needed, not
knowing when the next patch would be ready!
• Sparkler got too fibrous for us, as did Cherry Belle after mid Oct. We
like Easter Egg and White Icicle. Small radishes take 27–52 days to
maturity, not counting days too cold to grow.
• We decided to only make 5 sowings:
Sept 7 sowing of radishes on
Oct 3. Photo Pam Dawling

44. 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.

46. Corn Succession Crops
Using
data
from
12
years

47. 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

48. Cucumber graph with 15 years’ data

49. Bush Beans - several years’ data

50. Bush Beans – 15 years’ data

51. Scheduling for continuous lettuce harvests
• To harvest a new planting every week you need to have sowing
gaps of more than 7 days in the spring, 6-7 days in the summer,
less in fall.
• In warm spring weather, baby heads of lettuce or individual
leaves can be ready to harvest 4 weeks after transplanting, and
full-sized heads 6 weeks after transplanting.
• In summer, full size heads can be ready in as little as 3 weeks
from transplanting.
• In the fall, as temperatures and day-length decrease, the time to
maturity lengthens, and a single day's difference in sowing date
can lead to almost a week's difference in harvest date.
• Lettuce for February harvest will take 2-3 times as long from
planting as that for September harvest.
• December and January sowings grow very slowly, and early
February sowings will almost catch up.

52. Year-Round Lettuce Part 1
We aim to harvest 100-120
heads of transplanted
lettuce outdoors from late
April to November.
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,
For details see
Lettuce Year Round
on SlideShare.net
Photo Kathryn Simmons

53. Year-round Lettuce Part 2
• every 5 days in early August
• moving to every 3 days in late August,
• September sowings will be for growing
under protection only.
• If you do have coldframes,
hoophouses, greenhouses, sow cold-
hardy varieties every 2 days until Sept
21, then every 3 days.
• Or overwinter lettuce outdoors with
hoops and rowcover. Aim to have
plants half-grown by the time the very
cold weather hits. Try a few different
sowing dates, as the weather isn’t
very predictable. For us, Sept 10–18
are the best dates.
Cold-hardy (not heat-tolerant)
Tango lettuce.
Photo Kathryn Simmons

54. Hoophouse Lettuce
• We grow lettuce in our hoophouse to harvest from November
to April. (Thus we have two distinct lettuce growing graphs.)
• Avoid the need for new sowings at the slow-growing time of
year – transplant lettuce in the fall to remain in the
hoophouse until spring and simply harvest individual leaves
from the plants all winter.
• If you want baby lettuce mix reliably every week, use the
graph-making method to schedule sowings.
Baby lettuce
mix in
December
Photo Pam
Dawling

55. Lettuce Successions Graph

56. Lettuce Logbook – see next slide
• Record planned and actual dates of sowing,
transplanting, starting and finishing harvest of each
planting, for head lettuce from transplants.
• These exact dates probably won’t be right for your
farm, but you can see the general themes.
• Improve the sequence every year and get closer to
your goal of a continuous supply.
• The gap between one sowing and the next gets smaller
as the year progresses; the gap between one
transplanting and the next does likewise;
• The number of days to reach transplant size dips to 21
days in the summer, then lengthens as the weather
cools and the days get shorter.

57. Lettuce Logbook Page

58. For details, see my
slideshows Fall and
Winter Hoophouses and
Hoophouse Cool Weather
Crops on SlideShare.net
Other Winter Succession Crops in the
Hoophouse
We plan several successions of winter hoophouse such as salad
and cooking greens, and small turnips, as well as radishes.
Keep good records and eliminate sowings that are too late to give
a harvest – some crops bolt in January (tatsoi, Tokyo bekana and
Maruba Santoh); some in February (Yukina Savoy, Chinese
cabbage, pak choy).

59. Why Plan Winter Hoophouse
Succession Crops?• Make best use of that valuable space!
• Rate of growth is faster inside than out.
• In a double-layer hoophouse where it is
8F/5C warmer than outside on winter
nights, plants can survive 14F/8C colder
than outside, without extra rowcover.
• With the addition of thick rowcover
(1.25 ozTypar/Xavan), they can survive at
least 21F/12C colder than they can
outside
• That is, 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

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

61. 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

62. • Brassica Salad Mix #1, sow 10/2, harvest 10/29 -12/22
– #2, sow12/18, harvest ?-4/20
– #3, sow 1/27, harvest 4/15 - 5/15?
– #4, sow 2/1, harvest 4/15 - 5/26
• Chard #1, transplant 10/15, harvest 12/11-4/9.
– #2, sow 10/26, harvest 2/6-5/1
• Lettuce Mix #1, sow 10/24, harvest 12/11-2/21.
– #2, sow 12/31, harvest 2/21 - 4/15
– #3, sow 2/1, harvest 3/18 - 4/20 (3 cuts if we’re lucky)
– #4, sow 2/15, harvest 3/25? - 5/15 (in case outdoor lettuce is late)
• Leaf Lettuce: Succession planting is practical only until October. From November to March, harvest
leaves from the same mature plants.
• Mizuna (& other frilly mustards) #1, transplant 10/20, harvest 11/27-3/7
– #2, sown 11/10, harvest 2/26-3/20,
– #3 sown 2/1, harvest 3/24-4/23
• Onions (bulbing for transplanting outdoors March 1) #1, sown 11/10.
– #2, sown 11/22. #3, sown 12/6 as back-up.
• Radishes #1, sow 9/6, harvest 10/5-11/15
– #2, sow 10/1, harvest 11/6-12/25
– #3, sow 10/30, harvest 12/16- 2/7
– #4 sow 11/29, harvest 1/16-2/25
Our Winter Hoophouse Succession Crops

63. More Winter Hoophouse Succession Crops
• Scallions #1, sown 9/6, harvest 11/8-2/4.
#2, sown 11/13, following radish #1, harvest 3/19-5/15.
• Spinach #1, sown as sprouted seeds 9/6, harvest 10/30-2/15.
• #2, sown 10/24, harvest 11/25-5/5.
• #3, sown 11/10 as gap-filler. Harvest to 5/1
• #4, sown12/27.
• #5, sown 1/17, as gap filler. We pull up finished plants from earlier spinach
sowings and fill gaps with younger plants. All the later sowings are harvested
until 5/7.
• #6, sown 1/24, primarily to transplant outdoors.
• Tatsoi #1, sown 9/7, harvest 10/30-1/9.
• #2, sown 10/25-11/15, harvest 2/12-2/28.
• Turnips #1, sown 10/15, harvest 12/4-2/20 (thinnings 11/29)
• #2, sown 11/10, harvest 2/25-3/15 (thinnings 1/11).
• #3, sown 12/10, harvest until 3/20. This sowing is only productive if thinned
promptly and eaten small. Turnip greens are very sweet, beautiful, and
become available when veggie-lovers are hankering for some good fresh flavor.
• Yukina Savoy #1, transplanted 10/10, harvest 12/5-1/25.
• #2, sown 10/24, harvest 1/8 - 2/1 (only one week extra)

64. Extra 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.
• For the 6th and 7th plantings we sowed
only our fastest-maturing variety.
• We eliminated the late (and sometimes
unproductive) 7th planting and
increased the size of the 6th, sowing our
usual range of 3 varieties.
Silver Queen Sweet Corn. Photo Kathryn Simmons

65. Extra Benefits of Succession Planting:
Avoid chancy sowings: squash
• Before we made graphs, we used to sow squash on
Aug 7. This gave us an Oct 2 harvest start. Too late!
Now we sow Aug 5 and harvest from Sept 24. An
example of a 2 day delay in sowing in late summer
leading to an 8 day delay in harvest!

66. 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.
• When we moved the 2nd planting 10 days later than it used to
be, we were able to direct sow rather than transplant, and
saved time.
• No more dumping cucumbers on our neighbors’ porches!

67. 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

68. 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/benefic
ialinsect.html

69. 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 it worked to have a new patch coming on-stream every
36 days, we could sow only four times.
• Our squash plantings stay
productive for 40 days, but
cucumbers sometimes only
last 35 days.

70. For details, see my slideshow
Hoophouse in Fall and Winter on
SlideShare.net
Packing More Crops in
Keep the space filled with useful
crops.
It’s important to know when
crops will bolt, and how to plant
sensible quantities. Strategies:
• Transplant from outside in fall
• Follow-on crops,
• Filler crops for gaps
• Interplanting
• Fast catch crops for big gaps
December harvests Photo Wren Vile

71. “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

72. A sequence of different crops occupying the same space over time.
Sometimes confusingly called “Succession Planting”.
• We follow our 1st radishes with 2nd scallions on 11/17
• 1st baby brassica salad mix with 5th radishes on 12/23
• Some of our 1st spinach with our 2nd baby lettuce mix on 12/31
• Our 1st tatsoi with our 4th spinach on 1/15
• Our Tokyo Bekana on 1/16 with spinach for planting outdoors
• Our pak choy & Chinese cabbage on 1/24 with kale & collards for
outdoors
• Our 2nd radishes with our 2nd baby brassica salad mix 2/1
• Our 1st Yukina Savoy with our 3rd mizuna/frilly mustards on 2/1
• Some of our 1st turnips with our 3rd baby lettuce mix on 2/1
• More of our 1st spinach with dwarf snap peas on 2/1
Follow-on Winter Hoophouse Crops

73. 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 on your farm, in that particular
year, rather than generic “catalog” conditions.
 Simply using a calendar to determine planting dates 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.

74. 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
 http://farmprogress.com/mobile-apps has a free mobile phone
app!
 Using GDDs to schedule sweet corn plantings
https://extension.udel.edu/weeklycropupdate/?p=6618
 Using Heat Units to Schedule Vegetable Plantings, Predict Harvest
Dates and Manage Crops http://smallfarms.oregonstate.edu
 You can find growing degree days calculated for nearby weather
stations at some weather forecasting websites.

75. Using GDDs to schedule
sweet corn plantings
Gather the following information:
1. How many days you expect to harvest from that planting, (how
often you need a new planting coming on line.) .
2. The GDDs-to-harvest for the varieties of sweet corn that you
grow (or use your previous records of your first harvest for
those).
3. The average GDDs per day at your location during the expected
harvest period. Eg, if you plan to harvest for 5 days, multiply the
GDDs per day by 5 and plant corn this number of GDDs apart.
4. Add daily GDDs from planting until they equal the GDD in the
intended harvest period. When GDDs equal those in the harvest
period, make the next planting. Having your own maximum and
minimum thermometer is the best way do this. Information from
the nearest weather station is an OK alternative.

76. Using Heat Units to Schedule Vegetable
Plantings, Predict Harvest Dates and
Manage Crops http://smallfarms.oregonstate.edu/
• Search Using Heat Units to Schedule Vegetable Plantings, Predict
Harvest Dates and Manage Crops Nick Andrews and Leonard Coop
• Excellent article gives a table of lower development thresholds for
various crops, so that GDDs can be fine-tuned for different crops.

77. 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.

78. 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.

79. 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

81. Succession Planting
for
Continuous Vegetable Harvests
©Pam Dawling 2019
author of Sustainable Market Farming
and The Year-Round Hoophouse
www.sustainablemarketfarming.com
www.facebook.com/SustainableMarketFarming