Here is how you grow figs from winter die back to the ground to fruiting in the same season

General Fruit Growing
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Of course. And if you use a simple count of “warm enough days” then you also need to look at the total accumulation (i.e., a cumulative day count). My argument is that GDD gives an unreliable prediction. Explaining how to calculate GDD doesn’t make the prediction any better.

The key question is whether the GDD metric predicts plant behavior better than a simpler metric. Partly this is an empirical question, and the evidence I accumulated indicates that GDD is less reliable. Partly this is a question about the mechanics driving growth. Using GDD would be better if growth is controlled by a biological “dial” that increases growth continuously as the ambient temperature increases from,. say, 60 F (low growth) to 90 F (high growth). Using a count of days (or hours) would be better if growth is controlled by a biological “on/off switch” such that growth is near zero below some critical temperature (e.g., 55-60 F) but near maximal above that critical temperature. My data suggests that for figs, it’s a switch that goes ON at 60-65 F.

Yes, of course. But the same would apply for the “warm enough days” requirement.

OK but this doesn’t affect the criticism. It just changes the numbers slightly. The point is that the GDD metric accumulates superfluous heat.

I’m not saying that GDD is useless. Of course “it can give people an idea.” My point is that it is not the best metric. If you live in Georgia, you expect figs to ripen quicker because you have really hot heat. If you live in the North, you expect figs to ripen slower because you have merely warm heat. For example, suppose the average GDD requirement for Ronde de Bordeaux is 2500 GDD50. In GA, you might get to 2500 GDD in 75 days; you’d be shocked to find that RdR doesn’t ripen for another 20 days! In RI, you might get to 2500 GDD in 115 days; you’d be shock to find that RdB ripens 20 days early. With a day count metric, there are fewer surprises.

What I told you is that I did some of that work. Granted I looked broadly at time to ripening, combining times for fruit set, growth, ripening. But I can tell you with high confidence that the threshold for figs is ~60-65 F and that additional heat above that threshold doesn’t matter much. if at all.

Of course there will be more figs in an area with a longer growing season. Duh. That isn’t the issue. The question was about “ripening times.” In most discussions among hobbyist growers, this translates to something like “how much time is required for a fig to ripen its first fruit.” Whether a tree ultimately produces 10 fruits or 100 fruits or 1000 fruits is immaterial.

It ignores these differences because they are irrelevant to the question. If the growing season starts in Georgia on March 1, then RdB will ripen ~95 “warm enough days” later, maybe mid July. If the growing season starts in Rhode Island on May 1, then RdB will ripen ~95 “warm enough days” later, maybe mid-August. So long as the days are “warm enough” (i.e., >60-65 F), it doesn’t matter whether those days were hot (e.g., 90 F) or merely warm (e.g., 75 F).

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Just noticed this thread after I posted about seeing figs at one of my Zone 4b big box stores.
(Figs in Zone 4b)

Not sure how protected we could keep figs over the winter. We are known to have stretches of negative teens and negative 20s temps for 1-3 weeks at a time.

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Wow. This is literally an entire master class.

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Which varieties would you say are more cold hardy?

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Hardiness is multi-faceted:

  1. Figs that enter dormancy slowly and/or emerge quickly are more vulnerable to cold in early winter / late spring. Smith is an obvious example. I think the “Adriatics” such as JH Adriatic may also be in this category. Possible all late-ripening varieties.

In contrast, the Mt Etna’s (e.g., Marseilles Black, Salem Dark) drop leaves and lignify new wood quite early. I think they are relatively protected against this risk.

Red Lebanese Bekka Valley looks like a Mt Etna but tastes different. I suspect that it also is slow to reduce water in autumn so may be susceptible to damage from a freeze.

  1. Figs vary in their resistance to mid-winter deep cold. People that I respect think that Florea is relatively resistant. Based on its performance in my yard, I think that Lattarula / Italian Honey may be resistant. Otherwise, I don’t really have any good data. I doubt that good data exists

FWIW I’m skeptical that there is much actual variability in this trait, maybe a few degrees. Anecdotal stories about fig survival in sub-zero conditions are usually suspect because there can often be other influences. For example, a fig buried in 3’ of snow can probably survive -30 F. Snow is an insulating blanket.

I’ve had trees survive a 0 F winter unprotected with minimal damage but then die the next year after lows of +5 - 10 F. It’s inscrutable. I would not assume survival of any tree below +15 F, but you might get lucky.

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florea is the good one here, no protection and no damage. and early ripe so we actually get some edible fruit. CH ripen just at the end right as it’s getting cold and don’t taste as good

i don’t know if others are early ripe and fairly hardy. i do know CH isn’t

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At my place.. southern middle TN… my Chicago Hardy starts ripening figs mid to late August… and continues ripening fruit for 2 to 3 months. The latest I ever harvested ripe figs was Dec 3. That can be as early as early November just depends on when our first hard frost happens.

TNHunter

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Is that with or without dieback to the ground?

My protected in-ground Chicago Hardy, having suffered no cold damage, would probably start ripening figs in early to mid-September. So maybe 3 weeks after you. I no longer grow in-ground figs, but have stored data so I can check.

Meanwhile, you have WAY more heat than me, and your growing season is WAY longer. To my point, your season starts earlier so the figs ripen earlier. But all that extra heat along the way doesn’t seem to ripen your figs any sooner.

If you’re referring to in-ground trees with minimal cold damage (and if you are interested), let’s investigate the performance of the two metrics. Starting at the last day with a temperature <40 F (which is how I will define the start of the fig growing season) and ending on the date of the first ripe Chicago Hardy fig, (1) calculate GDD50; and (2) count the number of days with a maximum temperature >65 F. I’ll do the same using average historical data.

FYI, my recollection is that Hardy Chicago ripened after ~110 “warm enough days.” Starting roughly mid-May and assuming a few cool days in late May, that get’s me to early Sept.

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i haven’t had any from it yet but this year I’ll get data

i put in ground last spring. florea near it already had a ripe breba (!!?) and is making full sized figs now, but hasnt put on a lot of new growth upwards like yours do. it’s staying small sized but producing fruit. the CH is reaching to grow.

my other figs are all potted and somewhat babied so i can’t compare ripening times on those to what will happen to these.

have you tried florea there? i bet it would mass produce. that heat, it seems to love heat and probably wouldn’t die back as much with your bales system

edit- if you want to try it i have babies i can send you one in the fall, or next spring. they’re little rooted ones I’ve been putting up every year. a few have fruit. they’re just different enough to the CH that is not the same fig over and over again