greenhouse minimum temperature

[brian]

What temperature should I be maintaining my greenhouse at now that I have a bunch of true tropicals?  Previously I only had citrus and set my heater to turn on at 55F.  Should I be setting it a bit higher for jackfruit, annona, garcinia, guava, etc. ?

[00christian00]

At 55f you can keep most tropical, maybe even some ultra tropical.
If your goal instead is to have growth all year round, then you'll have to keept at least 75f.
At 55F most plants will do fine but won't grow.

[brian]

Thanks.  At my latitude there is reduced sunlight in winter months, so I'm not sure how much growth I can expect.  I'll be happy for things to simply remain healthy and resume growth come spring. 

[SeaWalnut]

Depends on the specie you have.You say you have annona but dont mention what specie.For instance annona Squamosa its tropical but cherimoya is subtropical and needs chill hour at least 10 days a year of chill with less than 7 C.
Guava also depends on what specie you have.I have strawberry guava wich and feijoa wich are subtropical and Ugni wich its a real temperate,cold hardy guava.
You need to find heat requirements for individual species.

[spaugh]

55 is higher than necessary for most of the stuff you listed. 

You would be better off setting it to 40 and investing in some grow lamps. 

[brian]

I have a chermoya, strawberry and true guavas, but also a ton of various tropical seedlings... too many to list. 

Any idea where I could find a list of the most cold-sensitive fruit trees?  Maybe I can keep the greenhouse temp lower but have a smaller area with supplemental heat for the most sensitive plants.

I could probably put the small tropicals under grow lamps as you suggest, Spaugh. 

this list seems to indicate there isn't *anything* that really needs >50F to avoid problems:
https://toptropicals.com/downloads/cold%20hardiness%20fruit.pdf

In fact, if I keep the purple mangosteen and malay apple seedlings warm I should be able to drop temps down to zone10 (30-40F) ?

Anybody disagree?

[SeaWalnut]

I have a chermoya, strawberry and true guavas, but also a ton of various tropical seedlings... too many to list. 

Any idea where I could find a list of the most cold-sensitive fruit trees?  Maybe I can keep the greenhouse temp lower but have a smaller area with supplemental heat for the most sensitive plants.

The cherimoya in my dome will be planted near a window and in order to make it chilled ,i planned to temporarely make a cover with plastic foil between the cherimoya and the rest of the tropical plants.
Basically il make a soird of temporary tent for the cherimoya and il keep the window open to chill it.
Thats because il plant the cherimoya in the ground,but cold hardy plants such as feijoa,do not mix well with tropical guavas for instance and il keef the feijoa in a pot ,bringing it outdoor for the chilling requirements.
True guavas are verry tropical,like sugar apples and they cant be mixed in same climate with cherimoya.
If you look at tropical countryes annonaceae that they grow,youl see they dont grow cherimoya and grow instead inferior quality sugar apples wich are suited for tropical climate whereas cherimoya is subtropical.

[brian]

In ground in my greenhouse I have citrus, jackfruit, canistel, and cherimoya.  Everything else is in containers.  If the in-ground stuff can tolerate 40F I can bring the sensitive container plants indoors while leaving the rest to receive some "chill" hours in the greenhouse.

[SeaWalnut]

In ground in my greenhouse I have citrus, jackfruit, canistel, and cherimoya.  Everything else is in containers.  If the in-ground stuff can tolerate 40F I can bring the sensitive container plants indoors while leaving the rest to receive some "chill" hours in the greenhouse.

Im not specialist in jackfruit but seems.to be a real tropical tree wich would not do well near a cherimoya.
Keep the cherimoya as far as the otther tropical fruits and make her a microclimate inside the greenhouse by opening a window .
You can grow cherimoya without chill hours but it will never fruit.Sugar apples are verry tropical and those you can grow near the jackfruit and will set fruit( they also make fruit a lot faster than cherimoya at just 1,5 years of age ,thogh the fruit is inferior to cherimoya,too sweet and too manny seeds).

[NickTheNZgrower]

This is a little off-topic but what heating system do people use for their greenhouses? I'd imagine gas is the best option because it is wireless. If so, what kind of gas heater?

Thanks!

[brian]

I'm reading that jackfruit are fine at zone10 which is 30-40F... which should be cool enough to count as chill for cherimoya, no?

Nick, I'm using natural gas which is relatively cheap.  It is *not* wireless for me, it has an electric ignitor and fan.  I have a battery-powered temperature alarm though and a manual backup system of propane heaters in case of power loss.

[SeaWalnut]

Keep in mind that the desired effect on chilling cherimoya ,is to make it go deciduous and shed its leaves.If you keep a tropical tree near the cherimoya ,it will probably loose its leaves and never recover after.Thats the case if you grow sugar apples and cherimoya together.Cold needed by cherimoya will kill the sugar apples and probably the jackfruit also.
Best thing you can do if you planted the trees in ground and cant move them,is to do like i do,a temporary separation  wall with plastic foil and you chill the cherimoya while the tropicals get no chill .Or you chill the whoole greenhouse and isolate with foil and heat the tender tŕopicals.
Jack fruit might be rated to zone 10 ,but if in zone 10 only the root survives and becomes like an anual perenial ,it wont make fruit and will die every year to the ground.( this is just a suposition since i dont grow or ever ate / seen a jackfruit tree/ fruit).
What otther seedlings you have?

[brian]

My cherimoya is recently grafted so I dont want to let it fruit yet.  I think I will maintain 50F this winter and see how the jackfruit handles it, then drop 5F each of the next two winters and see how it does.  I’m planning to build a second greenhouse at some point so I could have one for subtropicals and another for tropicals.

[brian]

What otther seedlings you have?

A bit of everything.  They are all very small, this is a test to see what survives.  Eugenias, garcinias, lychee & related, sapotes, jaboticaba, malay apple, caimito

[SeaWalnut]

What otther seedlings you have?

A bit of everything.  They are all very small, this is a test to see what survives.  Eugenias, garcinias, lychee & related, sapotes, jaboticaba, malay apple, caimito

Somme garcinias and somme jaboticabas might do well with cherimoya.
And until you get fruits from cherimoya,i reccomend you suggar apples that are real tropical  easyer to care providing you dont let them freeze and they bear fruits at a verry young age in pots.All you need to know about sugar apples its in this video. https://youtu.be/Lmf4Jgm9ETo

[Finca La Isla]

I guess I live in a tropical greenhouse here.  If this is interesting to you, the lowest temperature I experience where I have mangosteen, durian in production is 65f. The high could be only a few degrees above that.  In this range there is no setback during the winter.
Perhaps the hardest thing to really duplicate well is quality sunlight.  In late December we're probably getting about 11 hours of sunlight that is not way, way down in the south.
Peter