2. 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.
7. Fitting in 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
8. 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.
9. 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.
10. Planning for 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.
11. Several approaches to succession crop
planning – 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
12. 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.
13. “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
15. 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.
16. 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
17. 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.
18. 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 sweet corn
July16 (90 days before our
average first frost) and we
harvest from around Sept 22.
We sow our last edamame July 14.
We sow our last beans 8/3,
cucumbers 8/5.
Credit Brittany Lewis
19. 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
20. 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
21. 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).
22. Use sowing and
harvest start dates
to make graphs.
Four 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.
23. 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
24. Step 2. Mark the
first possible
sowing date and
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.
(Yum!) 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
25. Step 3. Decide the
last worthwhile
harvest start date,
mark that.
• Decide your last
worthwhile harvest start
date of the season.
• 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 (sowing)
axis to show when you
need to sow this batch.
• On this graph, an Aug 7
sowing produced an Oct
2 harvest start. That’s
too late!
• Now we sow August 5
and harvest from
September 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
26. 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.
27. 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
28. 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.
29. 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 2 weeks. The
planting intervals are 23, 18, 18, 13 and 9 days. The
intervals get noticeably shorter as the season goes on.
30.
31. Reminder of the main goals of planned
succession planting:
Continuous supplies of popular summer crops, such as
beans, squash, cucumbers and sweet corn; year-round
lettuce.
Avoid gluts and shortages.
Cucumber Generally. Photo credit Kathryn Simmons.
32. Fine tuning your
succession planting:
1. Save space and work
You may find you can plant less often, saving 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!
34. Fine tuning your
succession planting:
2. 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.
35. Fine tuning your
succession planting:
3. 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
36. 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
38. Fine tuning your succession planting:
4. 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, 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 2 weeks. The planting intervals
are 23, 18, 18, 13 and 9 days.
Silver Queen Sweet Corn. Credit Kathryn Simmons
39. 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,
40. 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.
42. Spring and fall crops: carrots
• We start sowing carrots as early as possible: mid–late February.
• Then we sow every 4 weeks in March, April, May, and, if needed,
June and July.
• We make a huge fall planting in late July or early August. If we miss
those dates, we wait till late August to avoid the high numbers of
grasshoppers here in mid-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.
43. 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.
44.
45. 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.
46. 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 and
www.farmprogress.com has a free mobile phone app!
There’s an article on using GDDs to plan dates for
succession sowings for sweet corn at
http://www.hort.uconn.edu/ipm/veg/htms/scpltsched.
htm
47. 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
SARE Crop Rotations on Organic Farms, A Planning Manual, Charles
Mohler and Sue Ellen Johnson, editors.
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.
48. Resources 2
Virginia Co-operative Extension Service Fall Planting Guide
http://pubs.ext.vt.edu/426/426-334/426-334.html
Growing Small Farms: http://growingsmallfarms.ces.ncsu.edu/ Debbie Roos
keeps this site up to the minute. Click on Farmer Resources
Cornell Extension website:
vegetablemdonline.ppath.cornell.edu/NewsArticles/All_BactSeed.htm Good
detailed information on seed treatments.
Manage Weeds on Your Farm: A Guide to Ecological Strategies, Chuck
Mohler (not yet published)
Purple Mountain Organics, Tacoma Park, MD. Tools and supplies
http://www.purpletools.net/protek-net-insect-pest-netting/
Brad Burgefurd, Cultural Practices And Cultivar Selections for Commercial
Vegetable Growers. Slide show. Wide scope.
www.slideshare.net/guest6e1a8d60/vegetable-cultural-practices-and-
variety-selection
Crop Rotations slide show
http://www.slideshare.net/SustainableMarketFarming/vabf-2013-crop-
rotations-for-vegetables-and-cover-crops-pam-dawling?from_search=5
49. 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 New Seed Starter’s Handbook, Nancy Bubel, 1988, Rodale Books
The Organic Farmer’s Business Handbook, Richard Wiswall, 2009, Chelsea
Green
Sustainable Vegetable Production from Start-up to Market, Vern Grubinger,
1999,
The New Organic Grower, Eliot Coleman, 1995, Chelsea Green
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
Nature and Properties of Soils, fourteenth edition, Nyle Brady and Ray Weil
Garden Insects of North America, Whitney Cranshaw
50. Succession Planting for
Continuous Vegetable Harvests
Pam Dawling, author of Sustainable
Market Farming
www.sustainablemarketfarming.com
www.facebook.com/SustainableMarketFarming
Notes de l'éditeur
Silver Queen.
There are methods of succession planting that involve no paperwork. This one uses the size of the previous sowing as a cue for when to make the next planting
Along the top bar are numbers of days before and after the average first frost. Crops are listed down the left side and the chart shows when you can plant and when you’ll be able to harvest.
You probably can’t read the whole thing, so here’s an enlarged example of one of the boxes at the left
The date in the Harvest Start column is the first day of harvesting from a planting sown on the Sowing Date in the first column. Note that these aren’t all in the same year!
X axis goes A-Cross. That’s the sowing date. Here I’ve just used a set of dates you might get from your first year, sowing 5 times.
Draw horizontal lines from the y axis from the 5 calculated harvest dates to the line of the graph.
Then draw vertical lines from where these horizontals cut the graph line, down to the x (sowing) axis.
In our squash example, April 18 on the x axis and June 1 on the y axis make the first point on our graph. Mark in all your points.
We once had an April 18 sowing that didn’t produce till June 1. I guess the plants got cold and set back. Ignore atypical points.
Make a smooth line, because it is more representative of typical reality and more useful.
Sometimes there will be “outliers” — odd things happen.
In the corn example later, the “blobs” marking the points are left in. Here they are hidden, so the line is clearer.
Draw a smooth line.
We used to do 6 plantings of summer squash and cucumbers: March 25 (transplanted April 20), May 14 (transplanted June 7), June 13, July 3, July 19, and Aug 5. The intervals between these sowings were 50, 30, 20, 16, and 17 days.
By using the graphs, we have been able to go down to 5 plantings: March 25 (transplanted April 21), May 17, June 21, July 16, and Aug 5, 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 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,
This meant that pole beans were a complete waste of time (they didn’t mature before the beetles ravaged them).
15 day intervals: April 16, May 20, June 9, June 24, July 9, July 22, and Aug 3.
“Root Checks” was our euphemism for pulling up the beetle-ridden plants, picking off the last beans, and taking the plants off to our composting area.
Once the parasites are established for the season, there’s no more need for hand picking beetles, and the second and subsequent plantings will look very healthy.
Our 6 sowing dates are on April 16, May 14, June 7, June 29, July 19, and Aug 3
Ignore the bizarre numerical dates
The season does finish a bit earlier than previously, but we get no complaints. The seventh sowing has always been risky because of deteriorating weather.
Allow time for writing
You can get the general effect from this, although you probably can’t read the small print
We scratch these hot-weather sowings if we still have spring carrots in the cooler, as the flavor of hot-weather carrots is not very good and we can get Alternaria blight, which turns the leaves black and so reduces growth.
Late August sowings don’t bring as heavy yields as the earlier ones, unless the winter weather lets us harvest later than usual.
Plants grow faster in warmer weather (up to a point!), whenever the temperature is above the threshold base temperature.
If calculations are not your forte, and you’re content with a rough figure, not specific to your farm, there's a calculator on www.weather.com/outdoors/agriculture/growing-degree-days. Simply enter your zip code, the base temperature to calculate from, and the start date and the finish date. For example if you want to see if you have accumulated enough GDDs to sow sweet corn, start from the beginning of the spring and enter today’s date and the calculator will show you the GDDs to date. If it’s more than 200 on a base of 50°F (10°C), you’re good to sow! A good site to bookmark, as you’ll need to return to it often.
There are many uses of GDD numbers, such as to assess the suitability of a new crop for your farm, estimate the harvest date of a crop, estimate heat stress on crops, predict pest outbreaks and
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.