Hi, I live in the Cariboo region of BC, where we will often not have a single frost free month of the year. I have three citus: a calamondin orange, a redblush grapefruit, and another orange which I don't know the type. I would really like to find a good reference book for growing dwarf and other citus indoors specifically, or largely. The calamondin does well, but I have trouble getting the others to flower and set friut. I'd really like to educate myself more or caring for them indoors, but most of the good references I've seen deal more with orchards or outdoor yard trees. Does anyone have any recommendations? This site has been very useful to me on occasion, but with our dial-up system at very slow speeds it is really difficult to navigate through it in a reasonable time frame. Thanks for any ideas.
DLT One of the ways I look for citrus books is by going into Google you could type in (indoor citrus) go to the top of Google open (more) and click on (books) many books are archived some may have a chapter or two removed but it will still give you a lot of information Scholar is also very good in finding research papers. Hope this helps. isaac
Thank you Isaac, I have found many books and papers on citrus, however none devoted to the unique challenges of growing citrus indoor only. By far the best information I've found to date has been through searching this forum. However, I was hoping someone knowledgable on this forum might be aware of ,and could recommend a book devoted to this subject. From the lack of responses I'm guessing there isn't anything. From the number of indoor citrus growing hobbiests present on this forum, it would seem there is an opportunity here for someone who has the knowledge in their head and would like to publish a book themselves! Millet? I'd be first in line to buy it! Cheers, Diane
Diane, very kind of you to mention my name. You are certainly not the first person to ask for such a book. I am sorry to tell you that I have never located a book providing quality instruction concerning containerized indoor citrus. I have quite a large library of books concerning the genus, but none provide much usable information on the subject of indoor culture. However, if I could recommend one book, that I have found to be a personal favorite I would recommend "The Biology of Citrus", by Spiegel-Roy, Eliezer E. Goldschmidt. If you would like some help with your trees, feel free to e-mail me at millet@netecin.net. I don't think it would be to difficult to get your trees blooming, or at least to discover why they seem to be having a problem. Take care. - Millet
The others aren't seed-grown, are they? Ditto. Of all the books on citrus I've read so far this is the one that I think most highly of and would recommend.
Thank you Millet, for that recommendation. I'll follow that up. And you too Junglkeeper. Regarding your question on the trees, no they were not started from seed, although I have a whole bunch of young (6 year old) calamondins growing too - not mature enough to fruit yet. I've had the calamondin for years. The others are newer, but all purchased as fruiting mature trees. Since they came, they have never fruited again. The Navel orange (not certain what type) did have a few flowers once, but they dropped and there was no fruit. The Redblush grapefruit came with one fruit on it, and has never even hinted at flowering again. The Meyers Lemon is to new to tell. I've read this forum on winter leaf drop, soil, fertilizing, and soil temperatures/dormant periods. None of my have been cool enough, long enough to go dormant for the time period discussed in other threads. There are new leaves growing. So the first question is: Would they need to be kept cool and go dormant in order to flower again? When the Navel did flower, I had it in a south facing sunny window. Does sun intensity effect flowering and fruit setting? Is it different for different citrus? The Calamondin flowered and fruited a number of times a year. It would flower when it still had lots of fruit on it. It hasn't done much in the past year, but I did some major pruning (it was taking over the room), and I understand from the forum that pruning would hinder the flowering. How long will I have to wait until the new growth will flower again? Sorry to ask so many questions, I do appreciate your advice. Diane
Diane, as you seem to live in an area with a lot of Sasquatch sightings, perhaps your trees are afraid to bloom. But we will still try to help them. Your trees do not have to go dormant in order to receive enough cold stress hours to bloom. Citrus trees ONLY produce vegetation buds, that will grow to produce ONLY additional foliage (leaves), not flowers. A citrus tree never produces flower buds. What actually has to happen for a citrus tree to end up with flowers is a process called differentiation. Differentiation is sort of a "magical" process whereby the vegetation buds are changed from a vegetation bud into a flower bud. This is caused by a process that is not yet fully understood, so it is normally referred to as being the result of the tree going through a "stress" period. Normally the stress comes from cool (not cold) temperatures, or a drought stress. In you case it is going to be a cool stress. If the tree does not go through the stress period the buds will not be able to differentiate into a flower buds, so your tree will again produce only foliage. In order to insure that your trees make the change, the tree must accumulate 600 -850 hours of temperatures bellow 68F (20C). To be sure that the vegetative buds make the change try for temperatures in the low 60's or even somewhere in the 50F's (13-14C). In your tree's case, because the tree did not have a heavy crop last year, they will probably only require around 600 hours of cool temperatures, perhaps a little less. These temperatures should start around November through December or January, but in your area could probably start now. After completed raise the temperatures up and the tree should bloom. The hours can be accumulative, and do not have to occur in one straight time period. When your tree blooms send me an orange. Some citrus varieties require more cool hours and some less. Calamondins require less. If I can be of any further help, feel free to ask. Take care, you live in a wonderful part of Canada (my second favorite country, only after my own) . - Millet
That is very helpful, thank you Millet. So perhaps I need to line up a Sasquatch or two to scare these little guys and stress them enough to bloom! Shouldn't be a problem, one came around again last night and got the dogs howling. One more question though. Can they be totally in the dark if they are moved to a cool spot? I'm thinking the root cellar, although it tends to be at about 10 degrees C down there. And just out of curiosity, not need-to-know, what would stress the citrus trees in SE Asia or Central America to cause them to bloom? Anyone know what the "natural" cycle is there? An orange it is, although perhaps I should dry it before putting it in the mail! Cheers, Diane
In tropical countries, where the temperatures never fall low enough to cause the tree to differentiate, it is the dry season that provides the needed "stress." In South America, and other tropical locations, the trees accumulate dry season stress hours, then when the rainy season returns, they bloom. However, because there is no period of cool whether, citrus in tropical countries do not turn orange when mature, but remain green. Therefore, it becomes difficult to know which fruit to pick and eat. About a citrus tree being kept in the dark. Here, I would hesitate to make a recommendation, for any one to follow, because I have never put any of my trees (131 varieties) under dark conditions during the winter. So what you do, your on your own. However, various castles of Europe that have long maintained rather large containerized citrus collections, which they show on the castle grounds during spring, summer and fall, are stored in the dark castle cellars during the winter months, and been done so for years. An important concept with containerized citrus trees is that a balance be kept between the foliage, and the root system (a citrus trees is a unit). This balance is a range, not an exact temperature. When the foliage is placed in the direct sun light, the surface of the leaf's blade can easily heat to temperatures in excess of 100F (38C), under these circumstances the root zone should be maintained at 70F (21C) plus. IF a citrus tree is stored in a cool dark location, the roots system can be held at perhaps 50F (10C). Remember 55.4F (13C) is absolute zero for citrus. At 55.4 or less the tree is "dormant". I believe it will work, and evidently it does, but I can't guarantee it. For trees stored in this manner, the foliage will need to be gradually reintroduced to direct sun slowly, to prevent sun scald. - Millet
