X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Growing Degree Days or Will it ripen in my area?

    Those of us in the north with short seasons or cool summers get excited about growing varieties that everyone here raves about. Or perhaps you made a trip to Italy, Spain, Portugal or even California in peak fig season and tasted some amazing fruit. And got very excited about growing them in your area. Certainly that describes me. I suspect it describes a few others reading this.

    Northerners face numerous challenges in growing crops that are inherently heat lovers such as figs. One is of course our extreme cold weather in winter. People in the North (excluding the mild PNW) have figured out numerous techniques to protect their figs in winter including covering them and putting them away in storage so that they dont get damaged severely in winter areas.

    The other challenge which is particularly acute in the PNW but not just confined to this area is the amount of heat required to ripen fruit. We just don't receive as much heat overall so figs native to Portugal, Spain etc have less chance of ripening a decent amount of crop compared to their southern friends. Lets discuss this topic in this thread.


    Growing Degree Days

    All crops are believed to need a certain cumulative amount of heat to ripen fruit.

    From: https://whyfiles.org/2010/what-are-g...ays/index.html

    The Growing Degree Day, or GDD, is a heat index that can be used to predict when a crop will reach maturity. Each day’s GDD is calculated by subtracting a reference temperature, which varies with plant species, from the daily mean temperature (we ignore values less than zero).

    The reference temperature for a given plant is the temperature below which its development slows or stops. For example, cool season plants, like peas, have a reference temperature of 40 degrees F while warm season plants, like sweet corn and soybeans, have a reference temperature of 50 degrees F.

    The total GDDs over a growing season is related to plant development. The development of plants depends on the accumulation of heat. Since cool season plants have a lower reference temperature, they accumulate GDDs faster than warm season plants.

    Unless plants are overly stressed by drought or pests, the total GDDs can be used to predict when a crop will reach maturity. Corn, for example, requires 1360 GDD to mature.

    GDDs can be computed using climatic information for any location. That computation, along with data on soil, water, and minimum and maximum temperatures, helps suggest which crops will grow best in a given region.

    Figs are basically warm season crops and we can use a reference temperature of 50 degrees F.

    How to calculate GDD for any location

    GDD is a cumulative index of the amount of heat accrued from the beginning of a season. Any accurate temperature chart will highs and lows for every day from the beginning of the season is usually a very good start.

    Wikipedia on this topic: (note it uses Celsius instead of Fahrenheit) https://en.wikipedia.org/wiki/Growin...DD_calculation

    A simple excel macro should figure out the GDD for any location once you have the high/low temperature information for any location.

    But you dont even need all that. This is pre-calculated for you on websites such as wunderground.com


    Lets say you want to calculate GDD for the entire year of 2016 in the city of Paris, France.

    Navigate to wunderground.com in your browser, search for Paris France,
    Click on history
    Then the custom tab
    Set the from and to dates appropriately: In this case Jan 1 2016 to Dec 31 2016. You can choose any two dates if you like.

    (There is a bug in wunderground that doesnt allow you to choose a span > 1 year.)

    Scroll down to see the Growing Degree Days (base of 50F) - In this case you should see 2414.

    Comments

    The number 2414 is much lower than most places in US with the exception of PNW. So anything that grows in Paris and ripens should do well anywhere in the US.
    Varieties such as Hative D'Argentueil are especially interesting since it refers to a Paris suburb and apparently does well there. So it should do well even in the PNW which gets comparable heat units.



    Another example: comparison between 2 locations

    A post on the F4F forum by a respected member mentioned that Lampeira Preta ripened on June 1st in Algarve Portugal. When will it ripen in Seattle WA?


    Calculate accrued GDD by June1st. -- 1400 degrees F in Algarve Portugal.

    Playing around the wunderground site: We notice that this amount of accrued heat units happen in late July. This passes the sniff test as this also coincides with the ripening of DK and other breba crop varieties in Seattle.


    Greenhouse and other considerations

    With the use of greenhouses and other mechanisms, it is possible to artificially alter the GDD in each location. I am ignoring greenhouses for now since we dont yet have good data with accrued GDD with greenhouses.

    If someone has a weather station set up in their greenhouse, I would much appreciate your data: high low for each day and when each fig variety ripens.





  • #2
    Great post! How well has it been empirically validated for figs? For example, are we reasonably sure that the 10 degrees between 50 and 60 are worth the same as the 10 degrees between 80 and 90?

    What about fruit set? Is there a minimum temp or number of DDs that is required for figs to set fruit!
    Joe, Z6B, RI.

    Comment


    • jrdewhirst
      jrdewhirst commented
      Editing a comment
      FWIW, I did a quick search. I found nothing on figs but I did see a discussion / graph for corn. The relationship was very non-linear. Between 50 F and 70 F, the impact of extra heat was relatively small; but between 70 F and 85F, the impact of extra heat was enormous.

      Should we be talking more about microclimate? It would seem that once temps get warm, every extra degree of heat on the immediate vicinity of the tree could be huge. That's for those of us who have inadequate heat.

    • AscPete
      AscPete commented
      Editing a comment
      'GDD is a cumulative index'

      Its also generalized but could be a very useful tool, the same way its used in commercial agriculture to extrapolate crop ripening and insect emergence, it can be used to predict possible fig ripening of any cultivar in any zone once a database of Fig Ripening GDD is compiled.

  • #3
    Thanks for sharing this info...

    It dovetails well with the fig ripening Rules of Thumb (30-60-90 days and Minimum Average Daily Temps), https://www.ourfigs.com/forum/figs-h...-ripening-figs . With a little effort this heuristic (a parallel Rule of Thumb) could be used to quantify any fig cultivar for cultivation in almost any zone or location using its minimum GDD to ripening.
    Pete R - Hudson Valley, NY - zone 5b

    Comment


    • #4
      Originally posted by jrdewhirst View Post
      Great post! How well has it been empirically validated for figs? For example, are we reasonably sure that the 10 degrees between 50 and 60 are worth the same as the 10 degrees between 80 and 90?

      What about fruit set? Is there a minimum temp or number of DDs that is required for figs to set fruit!
      Thanks!
      I dont think we have validated it sufficiently for figs. But there isn't anything special with fig trees compared with other crops.
      There are definitely going to be edge cases where it doesnt do perfectly well as in all heuristic formulae.
      Especially in extreme cases. For instance, GDD calculations also taper off at high temperatures. So temperatures at 100 degrees and higher will count towards 0 growing degree days.

      It will be very interesting if we were to start logging the max/min temperatures atleast in their area/greenhouse. This will serve as a useful repository for other fig growers who want to know whether something will fruit in their area.

      Comment


      • #5
        One question: Do we know whether the key variable is air temperature or ground temperature? For example, suppose we built a raised bed, surrounded it with thermal mass (e.g., containers of water, painted black), and planted figs inside. Suppose that the result was a 5 degree increase in the temperature of the soil in the raised bed. Assuming that the location is well ventilated, so there is no difference in air temperature, would the figs set fruit and/or ripen fruit faster???
        Joe, Z6B, RI.

        Comment


        • AscPete
          AscPete commented
          Editing a comment
          IMO, It would work like any Rule of Thumb, its generalized...
          It actually would be a combination of the 30-60-90 day and Minimum Average Daily Temperature Rules with specs for actual locations.

      • #6
        I checked conditions here: Measured in cooling degree days with a base of 50 F, 2017 (vs 2016) was 13% cooler in May and 17% cooler in August, then 63% warmer in October. The total difference was >1%. But late varieties did not ripen. So either (1) the cool and wet May delayed fruit set, or (2) the cool August delayed ripening, or (3) both; but in any case, the warmth in October was NOT enough to compensate.
        Joe, Z6B, RI.

        Comment


        • #7
          What was your aggregate GDD for 2016 vs 2017?
          Usually October is too late and it adds very little GDD.

          Comment


          • #8
            I assume you don't care about the part outside the growing season?

            2016, May - Sept, 2807. Oct 209. Sum 3016.
            2017, May - Sept, 2655. Oct 340. Sum 2995.

            Joe, Z6B, RI.

            Comment


            • ramv
              ramv commented
              Editing a comment
              Per @ascpete's second link, both this year and previous year were much above 15 and 30 year averages for your area. Setting climate change aside, these years were anomalous.

          • #9
            An on-line GDD Calculator, there are some limitations...
            http://www.greencastonline.com/growing-degree-days/home

            An on-line calculator with 15 yr and 30 yr and Current yr by zipcode...
            http://climatesmartfarming.org/tools...ay-calculator/


            Edit:
            jrdewhirst ,
            Note the GDD charts for Bristol RI for May 1 thru September 30, 2016 and 2017. 2016 was clearly warmer than average with this season 2017 being about average.



            Last edited by AscPete; 11-24-2017, 11:16 PM. Reason: added GDD charts for Bristol RI...
            Pete R - Hudson Valley, NY - zone 5b

            Comment


            • AscPete
              AscPete commented
              Editing a comment
              ramv ,
              Select your 'Regional Climate Center', some have a similar calculator...
              https://www.ncdc.noaa.gov/customer-s...limate-centers

            • ramv
              ramv commented
              Editing a comment
              Very interesting. Your post clearly shows the effects that Joe observed. The late figs are going to be unreliable for Joe's climate in a typical year.

            • AscPete
              AscPete commented
              Editing a comment
              ramv ,
              I'm in a similar situation to Joe...

              At my location the average season total is ~ 2400 GDD, some middle season and most late season cultivars will not ripen properly without some 'season extensions'.

          • #10
            ramv,
            excellent topic to get going; I truly appreciate it. I have used GDDs in my research on rare plants when I must decide when I must get to Wyoming, or Utah, or Montana to be able to catch a species in bloom in order to differentiate it from another similar species. I has saved me from driving trips over 2,000 miles to arrive at the wrong time. In my case I look at label info on herbarium specimens, note where and when (date) the plant was found, the phenological state of the specimen (flower, fruit, vegetative). I then use the dates from the specimen data to compute the GDDs to that point for the year on the specimen label and monitor the temps for the year I need to do the field work and try to match the GDDs for the years on the specimens data sheets and my year of field work. I have never missed. Weather Wundaground lists amateur stations for all over the U.S. A great Thanks to them for the data and their investment and efforts!
            As a fig grower in Zone 4, I am very sensitive to the need to know the degree days requirements of varieties of figs. Knowing for example that Pino or Bigbill have Florea ripening on date X is very useful to me but there is a missing variable that is location . When I know where Bigbill lives (thanks for the cuttings Bigbill !) I can then search Weather Wunderground for a weather station near him and start playing with GDDs and estimate when my Florea is likely to ripen and if it is worth for me to grow that variety. Of course one has to know wthether their plant and my plant are container grown or in-ground planted ( as everyone knows that makes a difference) and YES other factors play in the equation of growing and maturing BUT GDDs knowledge and those dates of ripening figs are worth a pound of gold!

            I look forward to an extended discussion and some data generation!
            Thanks ramv!

            This is a reposting from 10 minutes ago as my I'm Translator application put all sort of nuisance at the bottom of my post; hopefully now that I disarmed the add-on it will be okay.
            Marcel -- Zone 4b, St Paul, MN
            WL- Grantham Royal, Randino, Sweet George

            Comment


            • #11
              AscPete --
              Thanks. I was aware that 2016 was warmer, but I didn't realize that the difference was so large -- especially in July & August. In 2016, most of my later varieties were 1st year cuttings, so I wasn't focused on whether they produced.

              The good news, I suppose, is that the difference amounted to only 2-3 degrees per day. It seems like a relatively small effort toward improving microclimate would change an average year into an exceptional year -- for here.

              The bad news is that the difference between costal RI and other more southern areas is huge. So unless I get really serious about greenhouses and such, many varieties are out of reach.

              Question, following up on @LaFigue's comments: Are there any databases (or can we create one!) the relates fig variety x ripening date x GDD?

              And for open discussion: What are the best techniques for improving microclimate, including control of wind? At my site, there tends to be a steady breeze which can whisk away warm air that otherwise may accumulate needs the tree.


              Joe, Z6B, RI.

              Comment


              • AscPete
                AscPete commented
                Editing a comment
                You're welcome.
                There may be databases for commercial fig production in fig growing regions.

                Windbreaks, permanent or temporary fences and or hedges could provide the required micro-climate protection.

            • #12
              The GDD info could lead to the creation of a simple Fig Cultivar GGD for ripe figs and could also be added to the Fig Variety Database...

              For example;
              Improved Celeste EL ~ 100 days potted / outdoors, GDD for that period was ~ 2000 GDD
              My entire season is ~ 2400 GDD between last and first frost in zone 5B


              Unknown BryantDark ~ 120 days in-ground (main crop), GDD for that period was ~ 2100 GDD
              the entire season is ~ 3400 GDD between last and first frost in zone 7A
              Breba crop Unknown BryantDark ~ 90 days in-ground, GDD for that period was ~ 1500 GDD
              Last edited by AscPete; 11-25-2017, 10:46 AM. Reason: added 2nd example and breba crop GDD
              Pete R - Hudson Valley, NY - zone 5b

              Comment


              • grasshopper
                grasshopper commented
                Editing a comment
                The difference in soil temperature. If you use black plastic to heat up the soil in ground, it should catch up with the pots by up to 2 weeks.

              • AscPete
                AscPete commented
                Editing a comment
                ramv ,
                After looking at your (Seattle's) daily Hi and Lo temperatures between Jan 1 and Nov 29, 2017 its clear why the in-ground trees keep their breba figs... You have very few days below freezing (~ 18 nights and no days below 30 F this year) and the 'average' daily temps rarely ever fall below 30 F. in contrast my dormant trees are exposed to months of temperatures well below freezing and at least 4 months of full cold dormancy.

              • ramv
                ramv commented
                Editing a comment
                Yes AscPete, we have a nice mild climate, great for growing large fig trees but maybe not so good for getting main crop
                Upstate NY is a more challenging place due to your extreme weather.
                Probably zone is a good indication of whether or not you will get a breba crop. GDD is a better indicator of main crop potential.

            • #13
              GDD has been used extensively in Canada to identify/develop areas that wine grapes can be grown.
              It seems to take extensive work and studies seem to be specific to a specific location and specific crops. Canada has successfully developed at least 2 major areas for wine production Niagara Region and Okanagon Valley are now world class wine growers producers.

              Some notable work was done by Winkler(1974) in his work with French and German wine grapes in California found that the accumulation of 1390 degree days was the optimum for wine grape production. In German Rhine area the 944 was found as the lowest accumulates degree day acceptable for commercial wine grapes.

              Not aware of anyone studying GDD and fig growing to this depth since fig production countries have ideal weather for figs?

              Guess first thing is to develop the GDD Tbase for figs (for grapes its 10C, for grasses 5C). Then a whole lot of metrics and testing for many years. Of course factors such as drought, disease extreme weather fluctuations would negate GDD recommendations.

              Since we already know the cold sensitivity of figs GDD probably not required for the Califronias of the world. Maybe only a simpler model needs to be developed, such as comparisons of common fig type cultivars in a few areas like PNW , N.E. and maybe Norther EU?
              Pino, Niagara, Zone 6, WL; variegated figs, breba producers & suggestions welcome
              Breba photos / Main crop fig photos
              Canada Fig Growers

              Comment


              • Pino
                Pino commented
                Editing a comment
                Totally agree Pete. But it it would be a lot of work.

                On the positive side thanks to the many experienced growers with large collections so much is already known and shared on the fig forums.
                i.e. Can I grow Panache in ground in zone 6 and reap delicious figs? If I posted that question I would get a ton of answers and I could then decide whether I want to grow that fig in a container with help of a greenhouse or skip that variety and move on.
                I am sure I would also be advised on potential issues with splitting where GDD I don't think would shed any light on that type of important information.

                Not trying to discourage anyone from studying GDD for figs, only to say much of the information is already available thanks to the many generous fig enthusiast.

              • AscPete
                AscPete commented
                Editing a comment
                I don't think that it would be a lot of work because much of the required info is already out there.
                A simple hypothesis is that that early - middle - late ripening equates to approximately 1900 - 2500 - 3000 GDD respectively.
                Full Disclosure, I've been toying with this idea for awhile, it directly correlates to the 'existing fig ripening rules of thumb' which have empirical proof in commercial fig production / agriculture.

              • ramv
                ramv commented
                Editing a comment
                @Pino,
                It would be quite easy to compute whether Panache will grow in-ground in your location. We start getting Panache from California Central Valley around Aug 1st. Assuming Fresno, CA: that is a total of around 3450 F heat units.

                Niagara Falls doesnt get nearly as much heat units in an entire year. So you may rule out growing Panache in ground. Perhaps if you used some season extenders you may be able to do it.

            • #14
              Pino ,

              I don't think that a "study" is actually required, GDD index are an established protocol in commercial agriculture.
              IMO compilation of existing info can provide sufficient data to provide adequate 'average' individual Cultivar GDD Fruiting / Ripening indexes, quantifying Early, Middle and Late ripening Cultivars.

              Each cultivar can be assigned a GDD index which can be used as an additional tool to easily compare an individual's local seasonal GDD to provide an educated guess of a specific fig cultivar's suitability for cultivation at that location.
              Pete R - Hudson Valley, NY - zone 5b

              Comment


              • #15
                How Growing Degree Days (GDD) info can be relevant to the average fig grower when each cultivar is assigned its GDD index, its a simple 2 step process...

                1. Know your location's GDD ( total seasonal GDD) for reference...
                https://www.wunderground.com/history/


                in this example its ~ 2500 GDD (base 50)


                2. Compare it to the fig cultivar's GDD index.

                Cultivar - GDD

                Brooklyn White - 2300
                CCD Gris - 2600
                Champagne - 2000
                Hardy Chicago - 2300
                Italian 258 - 2900
                Italian Honey - 2100
                Malta Black - 2200
                MBVS - 2200
                O'Rourke - 2100
                Sals GH - 2300
                Takoma Violet - 2300
                VdB - 2400

                We could also quantify Early - Middle - Late ripening cultivars as 2000 - 2500 - 3000(+) GDD index hypothetically speaking...

                Reference:
                Using this site's info...
                http://www.greencastonline.com/growing-degree-days/home
                End date - Start date = Seasonal GDD (base 50)
                2884 - 330 = 2554 GDD

                First Frost Date = Season End date
                Last Frost Date = Season Start date
                Pete R - Hudson Valley, NY - zone 5b

                Comment


                • AscPete
                  AscPete commented
                  Editing a comment
                  BTW, the GDD indexes are for main crop figs, Breba figs are usually 30 days earlier and an equivalent amount of GDD less.

                • Mario
                  Mario commented
                  Editing a comment
                  Thanks Pete , that index is very useful to those of us in cold zones , is there more info available on other varieties?

                • AscPete
                  AscPete commented
                  Editing a comment
                  Mario ,
                  Ram V's spreadsheet has much more data inputs, Its in his signature line....
                  https://docs.google.com/spreadsheets...zD4/edit#gid=0

                  I only used my data and a few of Herman2's data as examples to show how simple it could be to apply the GDD (base 50) info. I've actually been using a similar data calculation for selecting fig cultivars for a few years using the available fig ripening dates, it was based on the elapsed time with daily average temperatures (the fig ripening stages), not actual heat index as with GDD but it creates similar "index numbers" for each cultivar.

              • #16
                See the linked article and the excerpt provided. The observation probably generalizes to figs. Thus, the degrees between, say, 70 and 90 F may count for more than those below 70 F or above ~90 F.

                http://agron-www.agron.iastate.edu/c...n03a/3a.4.html

                << While the assumption of GDDs is that corn grows linearly, that is not the case.

                Figure 3.7 illustrates with an S-shaped curve the response of corn to temperature. A growing degree day assessment of growth assumes a linear growth response. In actuality, corn begins to grow very slowly, as noted where both curves hit the axis at the bottom on the figure between 50° and 60° F. It grows rapidly between 70° and 80° F; at 85° or 90° F it hits the top of the curve. Temperatures above 92° F begin to become detrimental to the growth of the crop, and the curve starts to move over to the right-hand side.




                Fig. 3.7 GDD linearly simulated growth and actual corn plant growth influenced by temperature.
                That is the way corn grows. The line that is an approximation of the average right up the middle of the curve is the way the government THINKS corn grows. This is the growing degree day representation of corn growth. A growing degree day is a straight-line representation, so if the temperatures are hovering around 60° F, the actual growth line is far below the straight line. Actual growth of the corn is considerably below the predicted growth. If the temperature is 74° F, right in the middle where the two lines cross, the corn grows exactly at the predicted speed, or the growing degree day, line. If the temperature is 82° F, the corn is growing much faster than would be predicted. Growing degree days are a straight-line representation of the curved line which actually represents the growth of corn. >>
                Last edited by jrdewhirst; 11-25-2017, 06:45 PM.
                Joe, Z6B, RI.

                Comment


                • jrdewhirst
                  jrdewhirst commented
                  Editing a comment
                  Yes, it would result in a smaller value, but it might also result in a more useful, predictive value.

                  Consider the corn example. If someone tries to grow corn in an cool (maybe elevated) area with a long growing season -- say, 6 months at 50-70 degrees -- he could accumulate nominally enough GDDs but still get no crop. Similarly, if he tries to grow corn in a very hot (e.g., irrigated desert) area with a decent growing season -- say 4 months at >95 degrees, he'd have way more than enough CDDs but again no crop. What matters is GDDs between 70 and 90 F. If you really want to know how well corn will grow, that's the number you'd want to focus on.

                  Presumably, it's similar for figs though the ideal range might be different.

                  If the measure was developed and applied only in an area with a similar seasonal pattern (e.g., the northeastern U.S.), this nuance might not matter. But if the measure was developed using data from areas with very different patterns (e.g., southern CA as well as the Pac NW), it could be critical. For example, in Seattle between April and November there might accumulate enough GDDs (~2400, Base 50) to appear capable of ripening "early" varieties of main crop figs, but temperatures might never actually get hot enough long enough to make it actually happen.

                • AscPete
                  AscPete commented
                  Editing a comment
                  You have a valid point, but areas like the PNW and England are the exception rather than the rule.

                • ramv
                  ramv commented
                  Editing a comment
                  AscPete, even England and PNW are not exceptions to the rule in my (admittedly limited) experience. See my post below about the comparison between PNW and CA Bay area.

              • #17
                AscPete, Wonderful! I totally agree with you, it is not a difficult task. I have found it extremely useful in my botanical work. How does one know when to leave Minneapolis (MN) to search for a plant 1/2 inch tall and a couple of inches in diameter in the sagebrush in the semi-desertic area between Manila (Utah) and Mountain View (Wyoming)? GDDs for years of herbarium specimens & GDDs for the current year; "Elementary my dear Watson" !!!

                AscPete, your table of cultivars and their GDD, above, is exactly what I am trying to construct. It clearly tells me that I would be out of my mind to grow Italian 258, as its GDDs requirement is larger than the GDDs available to me in a good year like this year. I would have toI move since my historic neighborhood would not allow for a greenhouse.

                I certainly would be quite happy to work on building a database. What would be needed in my opinion is members providing the following:

                1. a specific date of the ripening of the fig cultivar;
                2. information about whether the plant is grown in container or in-ground (I would leave out in greenhouses as special cases);
                3. date when the potted plant was taken out of storage and put outside; or when was the wraps pulled from the in-ground plant;
                4. info on the age of the plant (1 year, 2 year, 3 year or more);
                5. Location of plant where grown (zip code, or town, or village, or general neighborhood for very large cities) so that one can get info from the appropriate weather station.

                Of couse individual members could build a table with the cultivars they grow and their computated GDDs and provide that info; then I could compile it into a database. Yes, there are all sorts of special situations but let's see if we can establish some general GDDs framework for our various cultivars.

                Cheers.
                Marcel -- Zone 4b, St Paul, MN
                WL- Grantham Royal, Randino, Sweet George

                Comment


                • AscPete
                  AscPete commented
                  Editing a comment
                  Data from members could probably be posted in a Separate thread (Topic) and the compiled data could be entered into a field in the Newly established online Figs Varieties Database,
                  https://www.ourfigs.com/forum/figs-h...s-for-database
                  https://www.ourfigs.com/forum/figs-h...se-intro-video

                • LaFigue
                  LaFigue commented
                  Editing a comment
                  AscPete, yes; I am all for keeping the varieties and GDD data together so that one does not have to look in different places for the info.

                • ramv
                  ramv commented
                  Editing a comment
                  Yes, having a new thread on GDD data would be very good. It should include whether the crop was grown in the ground or in a pot. Also whether a greenhouse was employed.

              • #18
                Cultivar - GDD

                Brooklyn White - 2300
                CCD Gris - 2600
                Champagne - 2000
                Hardy Chicago - 2300
                Improved Celeste - 2000
                Italian 258 - 2900
                Italian Honey - 2100
                Malta Black - 2200
                MBVS - 2200
                O'Rourke - 2100
                Sals GH - 2300
                Takoma Violet - 2300
                Unknown BryantDark - 2100
                VdB - 2400


                We could also quantify Early - Middle - Late ripening cultivars as 2000 - 2500 - 3000(+) GDD index
                ramv ,
                Are the GDD for the different fig varieties accurate or guesstimates at this point?

                DBJohnson ,
                Did you assign those GDD indexes to those cultivars as an example or is there a cultivar index somewhere that you referenced?
                The Fig Cultivar GDD indexes are all calculated, most are from my multiple season's cultivation of the same cultivar and a few are from the posted ripening dates from Herman2, at F4F. They are actual values, but really need mores samples for better averages.

                They were calculated using some information as mentioned by
                LaFigue , Marcel.
                1. A specific date of the ripening of the fig cultivar;
                2. Information about whether the plant is grown in container or in-ground (I would leave out in greenhouses as special cases);
                3. Date when the potted plant was taken out of storage and put outside; or when was the wraps pulled from the in-ground plant;
                4. Info on the age of the plant (1 year, 2 year, 3 year or more);
                5. Location of plant where grown (zip code, or town, or village, or general neighborhood for very large cities) so that one can get info from the appropriate weather station.
                My ripening dates were taken from the time / date stamps of my photos of plates of ripe figs, the individual Fig Cultivar GDD index was then calculated for those dates with the Weather Underground Calculator "FROM" the season start date "TO" the Photo's date, the resulting Growing Degree Days (base 50) are then averaged for multiple years. IMO it provides a very usable reference which doesn't need to be overly complicated and uses the already established GDD (base 50).
                Pete R - Hudson Valley, NY - zone 5b

                Comment


                • AscPete
                  AscPete commented
                  Editing a comment
                  ramv ,
                  Most were pot grown, Herman2’s and BryantDark are in-ground, but that is not really relevant to the GDD index as long as the start of the growing season is known.

                  Additional heat provided by a greenhouse would affect a calculated GDD index number, and would only be relevant if the inside high and low temperatures were used for the GGD data.

                • ramv
                  ramv commented
                  Editing a comment
                  The ripening date for each fig should include an annotation as to whether it was pot grown or ground grown. Pot grown probably speeds up harvest date by 2 weeks or more.

                • AscPete
                  AscPete commented
                  Editing a comment
                  ramv ,
                  The reason why I say its not 'relevant' is that the 'GDD indexes' for Unknown BryantDark (a Mount Etna type) and Unknown NancyLight (an Italian Honey type) has been the same for in-ground (in zone 7a) and potted in zone 5b for three (3) separate growing seasons.

              • #19
                Consider that perhaps, the region in which the fig is growing is not putting it's hardiness to the test.... For instance there are our beloved Mt. Etna varieties. Some of the cold-hardiest figs we know of, and because of this some of the most popular for cool climate growers... The Hardy Chicago probably being the most popular....Despite their elevation, the region these are said to have come from is still a USDA zone 9 or 10.

                I can't help but wonder if, given the amount of movement in Europe.. There might be many figs in warm climates that perhaps originated in much cooler places and haven't shown us their cold weather potential?

                I also wonder about overall plant hardness vs. fruit ripening time.... Can a late ripening fig tree be very hardy to cold? Can an early ripening fig not be very cold hardy? Or do the two necessarily go hand-in-hand?
                Guildwood Village - Toronto, Canada - Zone 6

                Comment


                • #20
                  Originally posted by LaFigue View Post
                  AscPete, Wonderful! I totally agree with you, it is not a difficult task. I have found it extremely useful in my botanical work. How does one know when to leave Minneapolis (MN) to search for a plant 1/2 inch tall and a couple of inches in diameter in the sagebrush in the semi-desertic area between Manila (Utah) and Mountain View (Wyoming)? GDDs for years of herbarium specimens & GDDs for the current year; "Elementary my dear Watson" !!!

                  AscPete, your table of cultivars and their GDD, above, is exactly what I am trying to construct. It clearly tells me that I would be out of my mind to grow Italian 258, as its GDDs requirement is larger than the GDDs available to me in a good year like this year. I would have toI move since my historic neighborhood would not allow for a greenhouse.

                  I certainly would be quite happy to work on building a database. What would be needed in my opinion is members providing the following:

                  1. a specific date of the ripening of the fig cultivar;
                  2. information about whether the plant is grown in container or in-ground (I would leave out in greenhouses as special cases);
                  3. date when the potted plant was taken out of storage and put outside; or when was the wraps pulled from the in-ground plant;
                  4. info on the age of the plant (1 year, 2 year, 3 year or more);
                  5. Location of plant where grown (zip code, or town, or village, or general neighborhood for very large cities) so that one can get info from the appropriate weather station.

                  Of couse individual members could build a table with the cultivars they grow and their computated GDDs and provide that info; then I could compile it into a database. Yes, there are all sorts of special situations but let's see if we can establish some general GDDs framework for our various cultivars.

                  Cheers.
                  @lafigue

                  1) Many of us here are out of our mind, so all good there

                  2) Growing figs where you think you can't is part of the reason many of use are here..... Hold on... Someone should write a book about that (http://stevenbiggs.ca/the-store/grow...think-you-cant)

                  .... So where there's a will... There's a suborn-ass fig-freak who's determined to make it work until they pull their hair out.... There are others growing in colder locations than you... This is where you decide how deep down the rabbit hole you wish to go.

                  First - Consider forgetting cultivar names.... My father grew ever type of fig there is... "the white ones and the dark ones". he liked both...

                  Do you have anyone else growing figs in your area? Because their figs are probably a good start....

                  Second - can you create a micro climate? Plant the tree next to a foundation wall? Can you build a figloo?

                  http://forums.gardenweb.com/discussi...-it-the-figloo

                  If you want to grow an I-258... Then grow one!
                  Guildwood Village - Toronto, Canada - Zone 6

                  Comment


                  • UKE4U
                    UKE4U commented
                    Editing a comment
                    Figloo....great word.....great idea....thanks for the link Joe! TorontoJoe

                  • TorontoJoe
                    TorontoJoe commented
                    Editing a comment
                    In Canada, I've seen fig trees with trunks like that maybe twice... John's in that link and another of an old Italian guy that's been burying it for over 30 years. That's rare up here.... Hopefully not for long... I've got trees in the ground for maybe 5 years now.

                • #21
                  Originally posted by TorontoJoe View Post
                  Consider that perhaps, the region in which the fig is growing is not putting it's hardiness to the test.... For instance there are our beloved Mt. Etna varieties. Some of the cold-hardiest figs we know of, and because of this some of the most popular for cool climate growers... The Hardy Chicago probably being the most popular....Despite their elevation, the region these are said to have come from is still a USDA zone 9 or 10.

                  I can't help but wonder if, given the amount of movement in Europe.. There might be many figs in warm climates that perhaps originated in much cooler places and haven't shown us their cold weather potential?

                  I also wonder about overall plant hardness vs. fruit ripening time.... Can a late ripening fig tree be very hardy to cold? Can an early ripening fig not be very cold hardy? Or do the two necessarily go hand-in-hand?
                  I dont think they grow hand in hand. I258 is hardy enough to grow in ground in 7a according to Herman2. So is Ischia Black. But neither is particularly early.

                  Comment


                  • TorontoJoe
                    TorontoJoe commented
                    Editing a comment
                    that's interesting to me....

                • #22
                  Great topic, Ram!
                  It seems like GGD could be a more precise metric for determining ripening time of fig varieties since it is a known fact that ripening slows down when the temperature is cooler.
                  I have always appreciated members' harvest reports when varieties harvests are listed in order by date, and translating these data points into the more universal GDD would streamline this information.
                  Jesse in western Maine, zone 4/5
                  Wishlist- ,Campaniere, Demos unk

                  Comment


                  • ramv
                    ramv commented
                    Editing a comment
                    Thanks for your comment Jesse!
                    There are a limited number of fig growers in each location but across the US we have every fig variety being grown. A GDD comparison will allow us to determine if something is even worth trying in our location.

                • #23
                  Having this type of information available would be fantastic! Especially those of us with shorter growing seasons and no greenhouse who are just starting a collection. I know I would rather not invest time and money in something that has zero chances of ripening for me! Thanks for considering pulling it all together!
                  “The best time to plant a tree was 20 years ago. The second best time is now.”
                  – Source Unknown
                  MA 5b/6a

                  Comment


                  • Zuny
                    Zuny commented
                    Editing a comment
                    I agree with everything you said. Very nice tool to have.

                • #24
                  AscPete and others who might be interested.
                  It might be simplest to put together a google spreadsheet with the following columns

                  1. Fig Variety
                  2. Your location
                  3. Grown in (container size/ground)
                  4. Average Fruiting date (for bulk of crop - to eliminate outliers such as too early or too late)
                  5. Greenhouse?
                  6. GDD to ripen fruit (computed column from location and average fruiting date)

                  Members can fill in the rows. Its ok to have multiple rows for a single variety. It will be more robust since a lot of data will be factored in.

                  If you agree, I am happy to kick this off (i.e. set up the spreadsheet and make a few entries)

                  Comment


                  • TorontoJoe
                    TorontoJoe commented
                    Editing a comment
                    If going international won't make things difficult... I'm in...

                  • ramv
                    ramv commented
                    Editing a comment
                    Large cities (international) are covered by wunderground.com. Toronto is there. (I just checked)

                  • AscPete
                    AscPete commented
                    Editing a comment
                    IMO,
                    3. To be useful in the database the fig tree has to be 3 years or older (in-ground or potted)
                    4. At least ~ 25% ripening Date

                    7. Season Start Date / Last Frost Date (for the GDD index calculation)
                    Last edited by AscPete; 11-26-2017, 11:17 PM.

                • #25
                  Typical fig ripening for Breba and Main crop figs in commercial fig growing regions...
                  https://naldc.nal.usda.gov/download/15714/PDF
                  Breba Figs:
                  Stage I ... Spring growth to quiescence (stagnant stage or stage II), 7 - 8 weeks
                  Stage II ... Quiescence stage 2 weeks.
                  Stage III ... Ripening 2 weeks.

                  Main Crop Figs:
                  Stage I ... Rapid growth to quiescence (stagnant stage or stage II), 5 - 6 weeks
                  Stage II ... Quiescence stage 3 - 8 weeks (depending on the fig variety)
                  Stage III ... Ripening 3 - 5 weeks.
                  Zip Code 95641, Isleton CA - HarveyC

                  Dates .....~ cumulative GDD
                  Apr 1 - Jun 30 - 1400 GDD
                  Apr 1 - Jul 31 - 2100 GDD
                  Apr 1 - Aug 31 - 2700 GDD
                  Apr 1 - Sep 30 - 3300 GDD
                  Apr 1 - Oct 31 - 3800 GDD

                  Harvey's Facebook photos of ripe figs with actual ripening dates...
                  https://www.facebook.com/pg/Figaholi...60029974057420

                  Extrapolating from the above info;
                  Breba figs should be ripening in late June - early July with ~ 1300 - 1500 GDD
                  Main Crop figs should be ripening in July - Sept with ~ 2000 - 3300 GDD
                  Pete R - Hudson Valley, NY - zone 5b

                  Comment


                  • AscPete
                    AscPete commented
                    Editing a comment
                    HarveyC ,
                    Thanks for commenting.

                    What was / is your season 'start' date or last frost if any?
                    I only used April 1 as a reference point.

                  • HarveyC
                    HarveyC commented
                    Editing a comment
                    We did have frost but I don't remember our last frost date as the more significant weather events here last winter was high rainfall and risk of flooding. We've had our last frost as late as April 8th, I believe, but that was about 5 years ago. Usually we have some growth starting in March, but I don't keep track of that. This past April the soil was still fairly wet and cool so plants were growing slowly (wet soils take a lot longer to heat up).

                  • AscPete
                    AscPete commented
                    Editing a comment
                    Thanks for the reply.
                Working...
                X