Chill requirements for different fig varieties

[Levar]

In the linked Dave Wilson article, he makes some interesting points about chill requirements

"In warm-winter climates, ... fruit growers sometimes find that a variety produces well with much less chilling than “advertised”. This could be because their locations receive relatively few hours of chilling below 45°F but plenty in the 45-55°F range (perhaps lots of foggy days), or because the variety’s chilling requirement is actually less than stated.

"Researchers suggest also that some varieties in the absence of cold are better able than others to "switch" to a heat requirement for triggering bloom and setting a crop."

So, is there anything substantive or revealing about the chill requirements for different varieties of figs? I live in Miami where we don't average more than 50 hours from 32-45, yet all of my figs fruit and break dormancy either early or on time - except in some cases with young trees. I'd like to find or help create a list of reliable varieties for people who live in places where we're never going to get 100 hours at ~40. Also, I'd like to figure out what varieties - if any - simply won't work at all in climates like mine.

Thanks for reading.

[fruitnut]

I think the only way you are going to make a list is by experience. Basically figs don't need chilling. They just need something to knock the leaves off and they are ready to go again. Drought, flash freeze, or even defoliation by hand or disease and they are off again.

[jrdewhirst]

That's interesting. I never thought of it that way. I always figured that there was some other trigger and the leaf drop was incidental. You're saying the the leaf drop per se triggers a new fruiting cycle.

[figtree]

I heard that apple growers in Fiji defoliate their trees to sort of mimic a dormancy. I Don't remember where I heard it so I cant verify, but it sounds Similar.

[DaveC]

Have you got any first hand knowledge, or any knowledge of what varieties don't need chill hours, this post was in 2015, so it would be interesting to see if you got any results. Iv read that one possible variety is Dalmatie, which is ironically very cold hardy.

[Levar]

That's certainly been true for me so far.

I wonder why, then, some websites insist on posting the 100 - 200 hr chill requirement. Maybe chill is required for optimal quality or quantity, with those things being important to commercial growers. Maybe just one or the other?

Or maybe, building off what Wilson said, acclimation could perhaps stress the fig in ways that wouldn't occur had the plant been grown in a more ideal climate. Truly just guessing.

[fruitnut]

They list 100 for grapes also. I think that's just a fall back number for things that generally do have a dormant period but really don't need any meaningful chilling. Many of the new low chill stone fruits and blueberries listed at ~200 hrs will often fruit without chilling. Grapes and those low chill blueberries can be forced to produce a partial crop in fall by pruning. They also may have a small bloom in fall if a dry summer is relieved by fall rains.

Apples can fruit in the tropics and in LA basin. Even some listed at 800 hrs or more. Other fruits like high chill stone fruits aren't as adaptable.

[dkirtexas]

Every so often this subject comes back up and it is amazing how often the same source is quoted. I read the source again to see if it had changed and actually said FIG instead of FRUIT, it hasn't changed. Figs do not need chill hours, it is not a fruit tree. If I am misreading the DWN article please let me know.

[susieqz]

i don't always allow dormancy .i put figs under HD lights to get extra growth thru the winter. they get no chill hours n are happy.

[AscPete]

Hello Susieq,
Welcome to Our Forum Community. Glad to see you here!

[COGardener]

I prevented my Sweet George from going dormant this winter in order to finish ripening the crop. This as Susie mentioned has allowed the tree to grow considerably, it is loving life in the garage green house. As are my 4 TC fig trees and my up potted cuttings.

[Levar]

Hey Susieqz and Scott,

That's good to know. Have you noticed any changes to the fruit quality or the yield by doing that?

[cyberfarmer]

I would venture to guess that figs don't need any chill hours. I am a common idiot, so my guess is worthless. I would be interested to hear if anyone has a cultivar that they think is not producing due to insufficient chill hours. Then, I would like to see if we can find anyone growing that same cultivar in climates where there are no chill hours and getting figs.

The only one that I have heard suggested not doing well in warm climates is Black Mission. I have a few 3 year old B.M. trees that have produced zero figs. I don't get much chill here. I don't know how many chill hours I get here. Not too many, but definitely some. I am more inclined to believe that my B.M.'s just need more time before I blame it on temps.

[BillSF9c]

> "The only one that I have heard suggested not doing well in warm climates is Black Mission. I have a few 3 year old B.M. trees that have produced zero figs. I don't get much chill here. I don't know."

Since B.M. us my present desire, it's troubling to hear. I have read of other chill requiring trees that were artificially put dormant by plucking leaves, or even torching them, just enough to get leaf-wilt & demise. The mechanism may just end sap flow upwards, allowing roots to store sap for spring.

I'm USDACHGZ 10b, now. Sunset 17, SF Peninsula.

BillSF9c

[mgginva]

I'm also not convinced figs need chill hours.

[COGardener]

Hey Susieqz and Scott,

That's good to know. Have you noticed any changes to the fruit quality or the yield by doing that?

Levar,

Sadly the tree only ripened one fig (which as amazing) and the rest dropped for reasons unknown to me. The tree as add over a foot in height and substantial branching, it started putting additional new figs (not Breba) which also all dropped but one. I had planned to let the tree go dormant, however I changed my mind and I'm going to let it continue growing. It has grown so much, I had to air layer it to reduce it's height a little to keep it out of the lights.

As far as fruit quality, I could not comment, that was the first and only fig I have had from the Sweet George.

[Figger]

Hi all. A delayed reply on topic. On this picture is my 4 year old ingroud tree. Variety is unknown to me, but my guess is probably a Bordeaux type fig.

Location of tree is Paramaribo, zone 13a? 100 % tropical by any standards. My inground trees ( 7 in total) doe not go dormant, in a sense that they defoliate, but they do experience a stagnant stage somewhere from December to January.

Fruit production is year round, with increased production from end of March to mid May and from end of August to end of November. These two intervals luckily corresponds with our dry seasons with higher temps 95/35 F/• and fewer rain.

[Johnson1]

Figger welcome to the forum. Thanks for your info and pictures of fig plants in a tropical environment. Interesting that your crop season is the whole year.

A while ago WillsC
commented that figs in tropical climates don't see any chill hours yet go into short dormancy.

Seems there are a few 'rules' that get repeated on the internet yet lack substantial validity. Besides the afformentioned example, the concept of figs requiring minimal nitrogen is another fallacy.

[The1FigMan]

Although figs are not a fruit (inverted flowers) many of the agricultural extensions and universities recommend about 100 to 150 chill hours for figs. Chill hours disrupt the hormones transferring between the leaves and the roots, allowing the tree to go into dormancy. Although this is not a "requirement" for the fig tree to set fruit, the articles I've read suggest the tree will become less productive the following year. I have not found extensive discussions on exactly why aside from suggestions on the change in hormones.

When a tree goes through photosynthesis, sugars are produced for the tree. As the weather starts to drop, the tree coverts these sugars to long chained starches for the cold months. When the tree comes out of dormancy, supposedly, the roots have a "pop" in growth. I suspect the pop in growth may support additional nutrient uptake for the heavier production?

Additionally, as the tree becomes colder, the tree naturally drops it's leaves through the abscission layer (layer between the leaf and the wood) hardening. This prevents less sap loss and naturally, preparing the tree for hibernation. I do not know if the slower loss of leaves through this process results in a reduction of hormones, causing the starch generation, but I speculate this has something to do with it.

All this being said, this is from just general reading I've come across. I have not tested this. I'm up in zone 7, and store all my trees in hibernation for the winter.

[Figger]

Johnson1 Thank you for welcoming me here. Just turned an enthusiast with figs and other temperate fruit. I have set-up 1 acre of land for experimenting with figs, persimmons, loquat and pomegranate. I am aware that my climate zone is different to most of subscribers here, however these insights on how fig trees behave in so called extreme conditions may help you guys in better understanding the tree.

@ The1FigMan, I have read scientific articles on the topic as well, which indeed gives the same information. As of yet I have not experienced any reduction in production or plant health. But again, the trees receive the full wrath of the Surinamese sun year round. Will let you guys now if any negative effects occur due to absence of chill hours.

[blaze]

My trees under lights lose leaves for no apparent reason, at various points during the winter, and then start again. They are never "chilled" I have fruit through February. The fruit begin to ripen again in May. My trees that went through this cycle have never been more productive. All of their fruit will ripen this year. Much of it outside. Only the latest varieties will finish off inside and under lights.

[Figpotter]

My figs have done well without any chill hours. I do stall all of my figs both my potted figs and hydroponic figs and trim them at least once a year including taking off all the leaves at that time. I reduce watering for a week or so and when they start back up they cycle through without any problems and produce figs. In fact the figs that I grow year round under led lights way out produce the figs that go dormant. They also get thicker trunks because they have grown for 12 months instead of 6 months. The only time I don't get figs is in May and the beginning of June when they are acclimating to moving outside.

[JCT]

Growers in the Philippines and Malaysia have reported no leaf loss, just a very short period of no growth (dormancy.) So really, no chill hours required.

[Lamda]

This is an old thread and apparently there are several threads on this topic but I created an account to reply as I was looking for similar answers. Seems the answer is "it depends" according to a study conducted in Brazil:

https://www.scielo.br/j/rceres/a/HGmdcX6YjfPGBrcJjF66W3s/#

"The effects of chilling hours on fig cuttings vary according to the cultivars and accumulated chilling hours (CH). The different accumulations of chilling hours (CH) impact the activity of antioxidant enzymes, as well as carbohydrates and nitrogen contents. The Roxo de Valinhos and Pingo de Mel cvs. requires less accumulation of chilling hours (CH) to break dormancy. However, Troyano cv. requires more, which explains its sprouting and late production in subtropical areas. This first report on the fig stem cuttings chilling requirement in Brazil will facilitate the breeding programs for low chilling requirement cultivars."