Crocston grapefruit on tree 1.5 years.

[Citradia]

This is the last of four Crocston grapefruits that my tree growing on FD, made last spring of 2015. The fruit has taken 1.5 years to mature, I think, due to lack of heat hours/heat units on top of this mountain. My satsumas mature each year in December though. I wonder if satsumas can mature in a climate with cooler summers since satsumas are more cold hardy, as a rule, than grapefruit and other forms of citrus. What do y'all think?

[Pancrazio]

Hey citradia,
I'm a fan of grapefruits and I’m definitively hoping to grow them in my place but, as you can imagine, I’m not completely sure that I’m going to get acceptable quality fruits (i have a well pronounced "sweet tooth" and while i love the bitter-acid complexity of grapefruits, the have to be sweet for me to be an enjoyable eating experience).
However, i was hoping to do what you are doing, that is, growing them for more than a year on the plant to have them ripen over the course of two consecutive summers.
I was wondering, how they turned out? How much cold did you plant take? I'm going to use bitter orange (or FD) as rootstock and Duncan/Enzo/Bloomsweet as scion. Can you help me with your tecniques and your results?

Regarding Satsumas. I have just a small plant that i have been growing for last 3 years. I'm my place the ripen fine at the end of October- November (I'm growing Miyagawa). I assume sastuma don't need very much heat overall because they come from Japan which is itself pretty oceanic and while there isn't very cold there in citrus growing place, i'm assuming there isn't very much heath either.

[Citradia]

Pancrazio, these are photos of last winter's protection for my Kimbrough satsuma and my owari. The Kimbrough is surrounded by a permanent wooden frame that I staple 4 mil plastic sheeting to around end of October when threat of first freeze. My other sats and Meiwa and Crocston and star grapefruit and Changsha are covered by plastic over PVC pipe frames that are temporary and easily erected and dismantled in fall/spring. I put small mason jar-size space heaters controlled by Thermo cubes in each tent/dome to help moderate temps. Each tree also has a 30 gallon black plastic garbage can full of water up against it too for added protection in case power goes out on cold nights. I pull plastic back on domes and roll one side of kimbrough's "greenhouse" up to vent on days when high predicted to be in 50's or higher. This past winter I think my low was only 10 degrees F one night; was a warm winter here. The two winters before were the lowest I've seen anywhere, with lows of at least 0 degrees F all night for two nights and hardly got above freezing even during the day for month of January two years ago. Last winter, my trifoliate hybrids and Ichang lemons and nansho dai dai went through winter in high tunnel with only barrels of water for protection and didn't fully defoliate. Winter before last they defoliated but flushed out in spring. I lost all hybrids two winters ago due to polar vortex since they didn't have space heaters like my satsumas. Even dunstan citrumelo and swingle citrumelo died ( over six feet tall) with only plastic wind breaks and wire cages around them filled with leaves when it was 0 degrees all night and freezing all January. The only one to come back from roots from that event was Thomasville citrangquat. Oh and yes, the Crocston I ate today was as sweet/good as one I'd buy in a store.

[Pancrazio]

Well i must say that growing citrus there looks quite heroic to me.
I do similar things with my mango but usually i don't vent it during winter because mangoes haven't any problem in dealing with 90+F temps even in a closed environment. But i guess that citrus can be quite different from mangoes in that.
Do you manage to overwinter fruits too?
Your input on grapefruits is useful and encouraging. Last question: did your grapefruit fall all by themselves or did you pick them up?

[Citradia]

I overwinter the grapefruit and kumquats and from October to December/January the satsumas too. I picked the grapefruit. I figured 1.5 years on the tree was long enough. I vent the citrus in winter so it stays dormant in case the power goes out and space heaters don't work. Once the power went out in s snow and ice storm and the high during day was 19 degrees; don't know what low was because I left home to stay with friend off the mountain that had power, so my Kimbrough had no protection that day and night but the small greenhouse and the 30 gallon water barrel in it. The Kimbrough did fine without dropping leaves because it stayed dormant from venting to keep it cold but not too cold.