I grew a mandarinquat from seed, and eventually left it in a container outside (in Olympia, WA, zone 8a) over the winter. It was not able to survive.

That was a colder than normal winter though, and this was growing on its own roots. During another more mild winter I left a Valencia orange seedling outside and it was able to later recover.

I had thought mandarinquat might have a little more cold hardiness since kumquat is supposed to be one of the most hardy out of all the normal varieties of citrus.

I read a post about someone else who has a kumquat tree growing in a Seattle neighborhood (presumably grafted onto trifoliate) and it survives.

It's not mandarinquat, but here's some Ichangquat seeds that were germinating:

(Ichangquat is a hybrid between kumquat and Ichang papeda)

If you want to see what it looks like outside now

Maybe it didn't get the best luck when it came to genetics for cold hardiness.

Socal - good to know that they aren't cold hardy. I plan to eventually have some indoor specimens and some in a greenhouse, so it's good to know that these may need to be among those who live inside.

Well, you never know, as long as you are in climate zone 8 or more, you might want to experiment. But I would suggest grafting them onto to Poncirus trifoliata before planting outside. You might have a chance in zone 8b. Of course it depends where you live.

Socal, I'm just on the border of 7b. A family member of mine I've helped for years with their citrus keeps theirs in a greenhouse in the same area. I've found they tend to have less trouble (in the event that the heater in the greenhouse goes out) with the varieties that have more cold tolerance. They haven't lost any trees yet, but they usually have to give the less cold tolerant ones a bit of TLC to get them back on rough years. Since I've had a lot of luck growing mine full time indoors, once I have the ability to, I plan to keep the less cold tolerant ones inside and keep the ones in the greenhouse that will have less trouble if there's an issue in winter. I don't know that I liked the mandarinquat enough to graft it, but I do hope to get into grafting in the future. Since these are seed grown, I'm not expecting much, so if they ever fruit it'll be a nice surprise, but they'll make good specimens to teach the kid to care for plants. I do have my eye on a few different varieties I can only seem to find budwood for, so I plan to try grafting those at some point.

Had a 12 ft tall heavy producing indiomandarinquat.... sawed it / topworked

Uncle If you had a heavily producing indiomandarinquat why top working it with something else.

Steve

Steve, maybe Molowacker just didn't like the taste. They're not for everyone, especially if space is at a premium.

Steve, the Indiomandarinquat fruit was junk compared to all the other stuff i grow. I force rank my citrus every year and the spreadsheet directs me as to what is next for shovel pruning. I grafted Kinkoji Unshui to the Volk rootstock as well as NZL. But the whole thing may have to go as that spot has been determined a "view" direction... so it all will get dug up and replaced with something very dwarf-ish.

Here is the IndioM in Feb 2019: Its so loaded with fruit that the branches are all bent over / down. Harvesting small fruit takes a lot of time and when you have over 70 citrus in the ground as I did at that time... the force rank directed the chain saw at the base shortly thereafter.

The Indio mandarinquat is one intense fruit. But they do grow on you. I liken them to a kumquat on steroids. But, if I could grow other sweeter fruit with ease, I'd probably not grow mandarinquats.

Uncle: I agree with you on the indioquat as junk fruit. I like the Meiwa much better. I also like the NZL much better. I have NZL, valentine, and Fukushu in ground and 8 in containers. I have the time to pick small fruits. There isn't that much total fruit to pick on my farm.

Dave: Why can't you grow sweet fruits. You are 5 degrees warmer than me. Due to diabetes I only grow low sugar fruit than is low in acid but still has good flavors.

Steve

Uncle: thanks for the response, good to know it can be productive.

Dave: I agree it can be intense, I'm not a huge fan (though I think it might make good marmalade), but my kid loves them. I think for those of us who don't have long and hot summers the sweet varieties are a bit more difficult.

Steve: how would you compare the meiwa with the fukushu? I've been curious about the meiwa as I've had a lot of luck with the kumquats and have considered adding one to my collection at some point.

Meiwa is very good tasting. It has a good sweet-tart flavor when picked while it is green/yellow. Sweetness increases as it yellows up and is sweet inside and outside when they are orange. I have not gotten a ripe Fukushu yet.

Steve

Thought I'd post an update. All of the ones with roots were planted in seedling mix and have been kept moist. All have now sprouted stems.

I'll be curious now to see how this turns out.

Another update, a few of them have sprouted their first leaves.

"Frieda's mandarinquats" from the grocery store I've had were great. I prefer them over nagami at least.

I planted several seeds but a lot of them died. The tiny leaves get burnt up. I've saved a couple stronger looking ones and put them in shade for now hoping the leaves don't burn up. I don't think it's fungal since this has happened to other citrus seeds I've planted in full sun.

Have you tried germinating them in a paper towel and bag, then moving to seedling soil?

I've actually never used the paper towel method, might have to give it a go next round

It works well. Another thing you can do is drop the seeds in a glass of water. The ones that sink to the bottom are more likely to germinate and be stronger seedlings. The ones that float or kind of float are less likely.