My recommendation to you is that you put some supplemental heat out there for the cool nights. Many of these tropical plants cannot stand temperatures as you describe. In other cases, the low night temperatures will induce dormancy.

Can you give some idea of what a tolerable day & night temp is for e.g. Lychees? I know they need some chilling to set fruit and in fact the trees in Florida can have problems fruiting due to lack of chill. The greenhouse does warm up a lot during the day, maybe 15 degrees warmer on a sunny day, and it only gets down to 40F on the coldest nights which is only a couple weeks a year. It isn't hard for me to make it warmer (just open the door a bit) but I don't want to waste energy heating it hotter than I need to.

Scott

Lychees CAN take slight freezing...32º is okay... they aren't truly tropicals. I don't know about the sugar apples.
The best thing would be to do your research before you acquire the plants... but I have found SOME are surprisingly tolerant. My manila mango survived a 32º spate last winter.... and I was told that if the manila mango survived that, then my guava will have no trouble. I like what www.fruitlovers.com says... 32º damage... 29º death.... stuff like that... so you know.

Scott,

Lychees can withstand light frosts relatively easily, so long as the plants are hardened-off and the cold does not last long. I know of a number of plants that have been overwintered outdoors in the S.F. Bay Area, and even in the CA Central Valley. It certainly gets below 40F in these locations during the winter, so your greenhouse should be just fine!

I'm not sure about the sugar apple, but I know the species has been fruited outdoors in Southern California -- any part of which would certainly experience winter low temperatures colder than 40F.

Neither of these fruits (or, as Heathen1 mentions, mangos and guavas) are "ultratropicals". Plants like durian, mangosteen, cacao, etc., are -- these are the plants that would probably be killed by cool but non-freezing temperatures.

One final point: lychees have the reputation of being very difficult to fruit in marginal locations/conditions. Any number of other tender plants (citrus, for example) probably would fruit more reliably for you.

But, I suppose, your Maryland conditions will probably help in that regard -- lychee plants will probably love your hot and humid summers. They are said to like wet summers and dry winters -- the exact opposite of conditions here in California. Your tree(s) will get heat and moisture during the summer, and it will obviously be easy for you to keep the roots on the dry side during the winter. Lucky you -- lychees are possibly the most delicious fruit in the world!

Thanks Ashok. I am not very knowledgable on tropical plants and didn't know about the tropical/utratropical distinction. I have talked with a few Lychee experts in Florida and their feeling is with the right varieties ("Emperor" in particular), and with enough humidity year-round, I have a reasonable chance of success. Apparently it is nearly impossible to grow them by moving them inside a normal room in the winter around here because it gets incredibly dry. The lychees like dry soil over the winter, but they still need high relative humidity in the air. My main focus really is on lychees, but I am going to try a few others while I am doing all the work to set things up.

Scott

Ummm... I am not sure that lychees like it dry in the winter. That sounds like someone talking from Florida. :o) California Rare Fruit Growers have some nice facts on growing Lychees...

Here is a link that might be useful: CRFG

Heathen1, to quote from Groff, one of the foremost lychee experts:
"not subject to heavy frost but cool and dry enough in the winter months to provide a period of rest."

He lived in the native habitat for the lychee, not in Florida. Today my impression is most of the lychee knowledge in the US is in Florida because that is where most of the US lychees are grown.

What I can't interpret about this quote is what exactly cool and dry enough is -- these things are very relative, think of the Alaskan vs the African interpretation!

Scott

Heathen1,

Check out the paragraph in the CRFG "Fruit Facts" entry headed "adaptation": "Cool winters with low rainfall are ideal for lychees." I've never tried growing lychees myself, and so I have no first-hand experience -- I'm just repeating what I've read elsewhere.

Scott,

I'm sure the "tropical" vs. "ultratropical" distinction would be frowned on by botanists. I've heard it used by hobbyists in California to distinguish between certain "hardy" tropicals (oxymoronic as that may sound) like avocados (plants that can generally grow well in the state), and what I suppose you could call "equatorial" plants like durian (plants that have basically no chance at all of growing outside of a hothouse).

If you think you'll be able to provide the right conditions, I can't argue with you putting your main focus on lychees. They are truly a fruit of superlative quality. One often hears that they are the most prized fruit in China, and hey -- over a billion Chinese can't be wrong!

Well... California is notoriously low in rainfall... most of you back east, when you get a drought, you get more rainfall than we do... so maybe it's all in the perspective. Also, they were talking about San Diego... not real high on the rainfall levels.
Well, hey, what do I know... do whatever.

I guess when lychee likes dry cool winters is referring to almost no rainfall or irrigation, in order to get a decent flowering, because if there´s water in the winter it just will send vegetative growth and no flowers. How cool? Nights with 10°C for about 2 months and no hot afternoon during that period of time. But you can always girdle some branches and get a nice crop (if you live in a hot place).

I have seen potted fruiting lychees in San Diego.

Heathen1,

Well, you obviously know quite a bit -- so please keep sharing!

I think the key thing (at least in California) is that cold, wet soil often spells doom for tender/tropical plants. Root rot can kill plants even if they are not killed outright by frost. So, with many plants, hobbyists often do their best to keep the root-zone relatively dry -- by planting on mounded soil or in raised beds, or even by covering a plant's drip-line with a tarp during the winter.

California is notoriously low in rainfall -- but we tend to get it all during the winter. That is why the issue comes up.

But you are, of course, right that it is all relative. Certainly I get more winter rain here in Northern California than they would in San Diego, etc.

Anyway, sorry, Scott, for hijacking the thread away from the topic of greenhouse lychees!

Thank you Ashok... The reason I say this, is my BF is Japanese, coming from a long line of Sacramento agricultural Japanese... every year, I get fresh lychees from them... So... they grow in Sacramento, regardless of CRFG. :o) But, I am not a lychee expert, so I shouldn't speak where I don't know.

Thats OK Ashok, its all interesting to me. I am now thinking I will shoot for 50F in my greenhouse, and I think I can reach that just by patching some holes in it. Since it is in the ground it gets a lot of warmth from the soil, plus one wall is the house. Also I will reduce the water in the winter so the soil is dry on top and barely moist at the 1-2" deep point. Sound good?

If anyone had any good ideas on the soil to use I would appreciate it. My plan now is to use abut 80% compost and 20% dirt from my yard, plus some mycorrhizal (sic) fungi. This is based on what I read about lychees liking soil rich in organic matter.

Scott

Scott,

I'm no expert, but I would guess that your lychees (and sugar apples, etc.) will be very happy. Rather than large pots, perhaps you could plant them in half-barrels -- I'm sure the trees would appreciate the larger soil volume. (Of course, you might have to enlist "volunteers" to help you carry the plants in and out -- but that should only happen twice a year.)

Heathen1,

(More thread hijacking here ... I can't help it.)
O.K., so your boyfriend, and/or his family, grow lychees (I assume that you're speaking of outdoor trees) in Sacramento -- please tell us more! I would be EXTREMELY interested to hear what cultivars they grow, what cultural practices they employ, how much fruit they harvest, etc.

I adore lychees, and no one I've been in contact with through rare-fruit circles has yet succeeded with them (consistently) in the area -- so I'd love to hear more about how your friends grow the plant. (Unless we're talking about a family business, and their techniques are a deep, dark trade-secret -- in which case, oh well.)

I have no idea! I will have to ask... Usually, the Ole BF just hands me a bag and says "Do you want these? So and so dropped them off" he doesn't like fruit, the freak! :o)
I get a lot of asian veggies that way too. Before WWII and they took the land away from his family, They owned most of what's now over by the Florin area...grew grapes and hops too.

Scott... I never recommend putting real dirt in pots... it shrinks especially if you let it dry out.... not a good idea for many reasons. That would be fine on the watering... I was thinking you'd do the same thing I do with my plumerias... not water at all... eeek! :o)If you keep it at 50º the chance of root rot might be lessened, but it might not be cold enough for fruit.

Great discussion!
scottfsmith, even 40f will not be a problem for lychees or sweetsop. Try to avoid hot dry air and cool dry air, tropicals will hate this. As mentioned by another member, I think many tropicals won't have a problem as long as you don't combined prolonged cool temps with lots of water. I think its one of the many reason you could grow many more tropicals in Florida than California(weeks and weeks of cool weather in winter). The problems we have with lychees in California is that they don't flower often probably due to the combination of many factors here like our wet winter. And if they do flower, they will set very few fruits, maybe due to the lack of humidity,polinators, or both. Sweetsops usually experience plenty of dieback and root rot problems in our climate also.

One thing about "emperor" is that it seems to flower consistently in California but setting any fruits is another issue.

Hello everyone,
Thanks for an enlightening thread. I am interested in knowing if anyone here is SF Bay area has succeeded in growing - a.Mango (Manila,Mallika,Kent) or b.Sugar apple (varieties?) c. bananas -- I am considering growing them in containers if possible.

By success, I mean, plant surviving with care (please explain what care) -- and did it fruit? Also does it fruit occasionally or reliably each season? Also, what is fruit yield like?

I am growing a containerized banana (too young to fruit) and have Indian Curry Leaves, which I successfully overwintered outside this season; and therefore am hoping to repeat this success with other fruit/edibles.

Thanks a lot! -- homey_bird

As for the soil? You will have to watch the PH. Most tropicals will thrive more in the acidic range. Some will even die if in the upper range 7.0+. Do an internet search on the plant. There will be plenty of sites describing the plant and requirements. Container growing can be fun. So far I've had good luck with mine. Be sure to order grafted plants for better success and better fruit. You should be able to select a smaller sized variety as well. Good luck.

Homey Bird,

For extensive discussion on growing tropicals/subtropicals outdoors in the S.F. Bay Area, check out www.cloudforest.com.

There were several in-depth discussions on growing mangoes in Northern California in February -- scroll down through the threads until you get back to postings from that month.

The short answer is that mangoes have been grown and successfully fruited outdoors in the region -- I saw a mango "tree" (really a large bush) growing outside (but against the wall of a structure) north of Davis in February, and the owner reported that he had harvested about 40 fruits from the plant last season.

However, mangoes are certainly (and obviously) not reliable plants in our area. They require a favorable microclimate, and even then they would probably be easily killed in a bad cold snap. They also require very good soil drainage in the winter -- cold, wet soil will probably cause root-rot. (So growing mangoes in a container or raised-bed, or on a mound, is a good idea.)

As for bananas: yes, it is possible to fruit bananas outdoors here. Lots of people have done it. But certain specific cultural practices are required, and, even then, success is not guaranteed (even for experienced growers). Again, check out the "Cloudforest" site for lots of discussion on this. (Several participants there are "hardcore" banana-growing hobbyists.)

I'm not sure if anybody has succeeded with sugar apples (A. squamosa) outdoors in Northern California. It is probably not worth doing, unless you are a dedicated Annona collector: the cherimoya is much more adapted to the region.

I had some problems with my sugar apples this winter. All the seedling's limbs had drastic die back. I even lost one that was around 3years old, die back all the way to a stump, just for experiment purposes I attempted a cherimoya graft on it in order to try to save the rootstock. These were kept in the greenhouse too. I think it didn't enjoy the low light, high day temps & cool night temps. I'm not really sure what happen, these seedlings have always overwintered outside under a patio just fine. I don't think I'll be putting them in the greenhouse anymore.