Have 3 Nagami kumquat trees in very large pots. They are on their 2nd year, and have been outside all summer.
They wintered inside by a basement window under quite expensive plant gro lighting, but did horribly over the winter- not so much because of the lighting, but because of spider mites.
I practically had to drown them in Neem oil to get them through, and of course any of the fruit they had was soaked in spider mite killer and disagreeable.
In fact, they pretty much had to grow back from the roots come spring. They eventually recovered quite well, though their tree form is lost (now bushes)... but they have fruited again. However, as fall carries on temperatures are expected to dip for the first time to 28 or 30.
I want to leave them outside as long as possible, since I expect them to do poorly again indoors and would like to get some fruit this time. But how long to wait?
What is the lowest temperature they can take before they drop fruit or are injured. I've heard Nagami are among the most cold hardy, and some pages say as low as 20. Should they come in the first night below 32, or can I get a few more weeks outside?