Issues/needs to grow tropicals/citrus in the far North

[Youcantdothat]

Just found this forum and had to join.  I'm planning/researching to do the improbable.  I'd like to build a tropical greenhouse in northern Wisconsin.  As I design it I'm running into questions that are hard to find answers to.  Hopefully the fine folks here can help?

My goals are lemons, mandarins, pineapples, avocados, mango, bananas and miscellaneous other oddities.  I hope to maintain 60 degrees at night but that will be a question below.  The footprint would be 40' by 24' with a 14' ceiling.  It would be an A frame running E/W with heavily insulated N, E and W walls.

Questions:
1.  My site gets plenty of sun in the summer but this time of year it gets filtered/partial light from 8:30-9:30, full sun from 9:30-1:30 and then shady from then on.  Is that enough sun for tropicals or citrus in the winter?  Are some plants better able to handle it than others?

2.  I'm hoping for 60F minimum at night but that could be unreasonable.  Which of these fruits can handle 50, 40, 30 etc for routine minimum temps?  And which can handle 50, 40, 30 etc for "once a winter" cold snaps?

3.  Are any of these species incompatible with the others?  IE it's easy to grow all except for X because it needs much wetter/drier/hotter/colder/etc.

Thanks in advance for your expertise!

[Daintree]

Howdy from Idaho!  We are into the minus temperatures right now at night, with an air inversion, so no sun for about 6 days.

Here are my thoughts, although my greenhouse is much smaller than yours.  I have a 300 square foot tropical house, attached to a  200 square foot citrus house.

I killed all my citrus the first couple of times by keeping them too warm and moist in the winter.  If you can divide your greenhouse and let the citrus get cool (under 50, mine seem to like in the low 40's in the winter), I would think they would produce for you.

All my tropicals tend to view winter as "the time to not grow".  They don't get enough light (hours or intensity) to fruit or put on a lot of growth (except the citrus), but they are very happy to hang out and wait for the other 9 months.

A big challenge has been heat.  I have a gas furnace.  Just switched from a 20,000 BTU to a 30,000 BTU furnace.  I LOVE it!  When the sun is out during the day in winter, it will hit 80 in there with the furnace off.  My bananas, mango and cherimoya, sugar apple etc did fine in the winter down to 50 with no problem.  Under 50 and you will lose mangosteen, cacao, etc.  I never had good luck with avocado, no matter what I did.

Be really careful to insulate your floor/foundation.  I was really surprised how cold some of the "kids" roots got in pots.  If you plant in pots you can move things around depending on the season. My greenhouse runs E/W and I do NOT insulate the north wall.  I have mirrors on the fence behind the north wall of the greenhouse to shoot more light in.  Also, in the late afternoon, I get a huge boost of sun through the west wall, and morning sun from the east helps heat up the house by 9 am.

I have temporarily moved all my citrus trees into the tropical house for a couple weeks while we are well below zero.  I have to use supplemental electric heat in the citrus house when it gets this cold, and it costs a lot.  Unless it gets down to 0 or so, the citrus do great - mid to high 30's at night, 70's during the day.

I grow everything in pots so I can move them around, although it is harder with the bigger ones.  Luckily I have a strong grandson1

Millet grows a lot of things in Colorado, and has been doing it longer than me, I think.  My greenhouse is 8 years old.  Love it LOVE IT!!!

Carolyn

[nullzero]

May want to look into LED grow lights to supplement lighting during the winter hours. There are plenty of decent cheap LED grow lights like these

http://www.ebay.com/itm/Bestva-1000W-Full-Spectrum-LED-grow-light-for-medical-plants-veg-and-bloom-/121829014880?hash=item1c5d933d60:g:CeEAAOSwXeJYGJsO

[LaCasaVerde]

1.  My site gets plenty of sun in the summer but this time of year it gets filtered/partial light from 8:30-9:30, full sun from 9:30-1:30 and then shady from then on.  Is that enough sun for tropicals or citrus in the winter?  Are some plants better able to handle it than others?

Will need sup lighting. Everything will survive without but will do better with more light.

2.  I'm hoping for 60F minimum at night but that could be unreasonable.  Which of these fruits can handle 50, 40, 30 etc for routine minimum temps?  And which can handle 50, 40, 30 etc for "once a winter" cold snaps?
All my plants which is most of all you listed do just fine with temps down to 40. Id set your temp range 45-50. I keep mine at 40 and have had no prob. 60 will be a lot more expensive.

3.  Are any of these species incompatible with the others?  IE it's easy to grow all except for X because it needs much wetter/drier/hotter/colder/etc.

If in pots you control the irrigation. Most plants will figure out there is less light and heat units and will slow or stop growing during this period. Id seperate what you want to grow into sections as mentioned. Providing for each set of plants as required. It is too extensive to list all the requirements for each type of plant. Id keep it simple and put your most cold tolerant species together in the coolest part of your greenhouse and the plants requiring more heat closer to heat sources weather barrels, heaters, inground heating and so on.  For me  the ability to control the main variables -temp, light,  irrigation are the most important. Once you have these three things accounted for ...the plants will be happy regardless of species as Id say most all are compatible with each other. Im sure there are exceptions but this is the general rule. So... design a greenhouse that can hold say 50 degrees, have the ability with supplemental lighting to provide 8 plus hours of light, be able to provide water and you can grow anything you want. Sounds simple and it is...getting to that point is not so easy. Brian I believe has an excellent thread on this exact topic.
Welcome to the forum! There are many here with greenhouses. Many with much more experience and tips than I. Ive found we all like to share what we can to help.

[forumfool]

You should contact this guy; he has done this in zone 5 and would have valuable advice for you...

http://www.tropicalfruithunters.com/galleries.html

[Youcantdothat]

Thanks everyone for your responses.  Now I'm even more encouraged to give this a shot.

Daintree - That's very good to know about citrus coolness in winter.  I think I can subdivide my greenhouse.  The main heat source will be at one end so I should have a gradient (accidental or intentional) as you go across the building.  I'm also happy that you can keep them all alive at 50.  That will be easier to maintain 

So if I understand you correctly, you don't use supplemental light?  And the citrus still produce?  Neat!!

Maybe my greenhouse plans are too big...  How many tropicals and citrus do you fit into your two houses?

LaCasaVerde and nullzero - I can certainly put lights in the plan.  Is there a way to know how much better they'll do with additional light?  I'm not sure how to evaluate if it's worth the cost for the lights and the electricity.  I'll have enough juice at the greenhouse that I can add them later, I guess...

That's really cool that they all do ok down to 40 for you.  That's even easier to maintain than 50   Holding 45 should be very doable if my design works out.

I think I'll start in pots for exactly the reasons you mention.  Once I'm happy with how it's going, I may put some in the ground so they can really take off.   My soil is a bit sandy.

Forumfool - Thanks for the reference, I'll give Jay a shout.

[LaCasaVerde]

aCasaVerde and nullzero - I can certainly put lights in the plan.  Is there a way to know how much better they'll do with additional light?  I'm not sure how to evaluate if it's worth the cost for the lights and the electricity.  I'll have enough juice at the greenhouse that I can add them later, I guess...

Your building a large greenhouse. A failry expensive undertaking.  Id look at removing any sun obsticales (trees and such) or locate to an area that receives more sun.  5 hours -- really 4 hours of full sun is not optimal but doable.  You need the heat from the sun to offset heating costs. With the second half of the day cooling- suplemental heating has to replace this loss. Lighting then would also take over. I have access to a  seperate 100 amp service with mine (which is way more than enough for me), Id probably recommend you add this to your plans. Then when you go to lighting your greenhouse your not caught with insufficient juice so to speak and can pick out the lights you actually need.
 

[nullzero]

Any good quality LED grow light above 200 true watt would be substantial to help areas where plants grow even ripen fruit into the winter months. Investing in the ability to run up to 2000w of LED is only going to help the GH. The LED will also emit some supplemental heat. I would look into installing a support system for hanging fixtures.

The nice thing about the LED grow light is you can start slowly with a few units and see the results first hand.

You may want to look into heated floor as well using PEX tubes and hydronic heating. Was reading a lot of heat loss is through the ground, so having insulation foam buried around the edges in the ground may help. Also concrete slab will help retain heat.

[Daintree]

Daintree - That's very good to know about citrus coolness in winter.  I think I can subdivide my greenhouse.  The main heat source will be at one end so I should have a gradient (accidental or intentional) as you go across the building.  I'm also happy that you can keep them all alive at 50.  That will be easier to maintain 

So if I understand you correctly, you don't use supplemental light?  And the citrus still produce?  Neat!!

Maybe my greenhouse plans are too big...  How many tropicals and citrus do you fit into your two houses?
greenhouse that I can add them later, I guess...

I do use supplemental light to extend day  length, but only in the form of nice, cheap shop lights with cool white bulbs.  I have them on cords so I can keep them about 8 inches above the tops of the trees. Great article from the U of Alaska about using shop lights.  I would LOVE to get LED lights but can't afford the initial cash outlay.  The very second I hit the lottery, I am buying Black Dog LED grow lights!!

In my 200 sq ft citrus house I have 9 different types of citrus, baobab, loquat, fig, guava, and a few other things. Citrus always bloom every winter - are blooming now.  But, we DO get lots of sun most of the winter (we get over 200 days of sun per year).  I think intensity makes up for hours???

YES, make different zones in your greenhouse.  the mangosteen doesn't like anything lower than 60F, and the cacao REALLY don't like to be lower than 55F.  I move things around a lot depending on the season.  I also have tennis elbow and golfers elbow from moving all the pots.  Hire a neighbor kid to help with the pot moving!

I would not think your plans are too big, as long as you have an unlimited budget for heat.  My greenhouse costs more to heat than the house.  But, it is still cheaper than showing horses!  I tried many passive heating options, but with tropicals, you just have to have powerful heat.

In the tropical house (300 sq ft) I have over 140 specimens of about 65 species.  I try to avoid dioecious plants, but I do have multiples of some, and am waiting to see if they are "boys" or "girls" so I can eliminate the surplus. I also have Bourkes Grasskeets living and flying around loose out there.

Everything is in pots - up to 25 gallon size.  The greenhouse is only 15 ft wide, so the soil, even in the center, gets very cold in winter and would kill most tropicals.  Plus, we flood irrigate, and in pots, I can control the water way better.

Remember, you can always add on if you want more space.  That is what I did - 300 sq ft in year 1, then added 100 sq ft in year two, and the last 100 sq ft in year 5.

It is my little tropical oasis.  Lots of really fun work. Couldn't get by without it.

Carolyn

[bsbullie]

You should contact this guy; he has done this in zone 5 and would have valuable advice for you...

http://www.tropicalfruithunters.com/galleries.html

Yeah, contact Jay.  He should be able to give you some very good insight.

[Youcantdothat]

Thanks again for all the input! 

I'm planning on insulating the perimeter foundation to 4' deep to keep frost away.  So the ground should naturally be at 40 degrees give or take.  I'm also going to run warm water lines a foot deep through the soil so I can heat it up if needed.  If everything stays in pots, maybe I will just let it stay cold.

I like the idea of adding lights if needed.  Nullzero, are you saying that 2,000 watts of LED light would be enough for my whole greenhouse?  And is that the actual consumption or the equivalent to old light bulbs?  IE you buy a 9W LED for your kitchen, it gives off the same light as a 60W incandescent.

Carolyn, I just found the U of Alaska article.  If I do the math right, to simulate full sun you need 3 fluorescent tubes per foot (each tube does 10 watts per foot and full sun is 30 watts per foot).  Seems like a lot of light fixtures.  Or do you just do a few here and there to just give them some light?

Regarding obstacles, I only have a couple locations where I can put this greenhouse.  The best one from an access and power perspective has full unblocked sun from 10-1:30 and then filtered sun for an hour either side of that (at this time of year).  I can't cut the offending trees because they're too valuable as trees     The other spot currently has no sun but if I cut down about 80 trees it should get sun for 5 hours at this time of year.  Once we're to February the sun situation should get a lot better.

Do some of these trees do ok with just filtered/partial sun in the winter?  My second best location listed above does get filtered sun through deciduous tree tops in the distance.  But on cloudy days (half the time) the light is diffuse anyway.   My solar heat gain would be limited but how would the plants do?  They'd basically have partial sun from 9 till 3 from mid Nov through mid Feb.  Unless I did the tree massacre...

I love my woods but sometimes I wish I had a big boring field.....

Part of why I'm planning such a big greenhouse is possibly because I don't know how much you can fit into a given space.  Or how much food you can get from a given tree.  My winter light/temperatures may limit my production but my hopes would be for:
100-200 lemons a year
100 clementines a year
1 avocado a day when they're in season
2-3 banana plants
20 pineapple plants (unless that's silly)
1-2 mango trees

So how much room do I need to do that?  Sorry if that's an unknowable question...

Thanks again for everyone's help on this!!

[nullzero]

You would have 960 sq ft of total space. A grow LED with around 300w to 400w per hour will cover 4'x4' to 5'x5' depending on the quality of the light and if you use reflector walls around the area.

About 20 sq ft will be covered I would say you would need about 25 grow lights to cover most of the green house if it was stationary.

Figuring you got about 700 sq ft minus the path ways and spacing. You then would need to be able to power upto 10kw per hour if stationary.

My recommendation was for supplemental lights or focusing on a section of plants. I think you can do 10 grow lights and have them move on a rail system automated. Have them move every 4 hours to a different section, repeat cycle all day. This way you are using let's say 3.7kw per hour.

Figuring you run 3.9 kw per hour all day. It will cost you around $400 a month in electricity at .14 cent a kw.

I would use a cob led grow light similar to this https://www.amazon.com/gp/aw/d/B01DDC052E/ref=pd_aw_sim_sbs_86_1?ie=UTF8&psc=1&refRID=ZN9VARKFCJET75804SP0#productDescription_secondary_view_div_1483737244860

Here is an idea of a rail moving system. You would need one where it had a timed relay to move back and forth down the track.

https://www.1000bulbs.com/product/91854/GROW-LR35ID9KIT.html?gclid=Cj0KEQiAnb3DBRCX2ZnSnMyO9dIBEiQAOcXYH5bJe0Msi4WAqunFjY4dEh5aPCOHB2p0eMG0te8A_dUaAoXH8P8HAQ

Also buying the grow lights in bulk you may be able to arrange a discount saving you a upto a hundred or more in savings.

You can get 10 suitable grow lights for under $2k. Then have to figure out s decent rail system for around the same price.

[Youcantdothat]

Thanks Nullzero for the light info.  That really helps put it into perspective.  I've been tracking the sun today and watching which trees are in the way.    Maybe I could light up one half of the greenhouse for 4 hours before the sun hits those plants, then move them to the other side and light those plants up for the 4 hours after the sun goes down. 

I'm assuming that plants like their 8 hours of sunlight in one continuous stretch, right?  Not four hours at 1AM and four more hours at midday...

[nullzero]

A continuous stretch of light is better. I have ran LED lights for 20 hours on and 4 off. You really have to experiment, depending on the plant it will respond differently sometimes it triggers flowering and flushing on different light schedules, other times it can slow down growth rather then speed it up. Usually more hours of light means faster growth.

Most tropical plants prefer more then 12 hours of intense light for faster growth and more flushes. Annual vegetables and hibernating plants it would confuse more, with things like early bolting and slowed growth etc.

[Daintree]

Thanks again for all the input! 

Carolyn, I just found the U of Alaska article.  If I do the math right, to simulate full sun you need 3 fluorescent tubes per foot (each tube does 10 watts per foot and full sun is 30 watts per foot).  Seems like a lot of light fixtures.  Or do you just do a few here and there to just give them some light?

. . .
100-200 lemons a year
100 clementines a year
2-3 banana plants
20 pineapple plants (unless that's silly)

When I do lights, I put four 4-ft shop lights right next to each other. This gives me 8 bulbs (2 ft) wide by 4 ft long.  I have my citrus trees pruned down so that 3 of them fit under one bank of lights.  I just picked about 25 lemons and 20 limes from one lemon tree and one lime tree, to give you an idea of how much space I use for citrus. The trees are only 3 ft tall.

Bananas - LOVE them, but they block a LOT of light, so place them very carefully!  I don't have bananas now because of that plus I was tired of cavendish, and they ALL ripened at once and we couldn't keep up eating them.  I will get more next year though because I miss them, but will go with something other than dwarf cavs.

Pineapples - they take up waaaay too much space for me.  One pineapple plant will take up a 3x3 ft spot and give you exactly one pineapple in its life.  But they are fun, and boy do they smell good as they ripen!  If you leave one on the plant until fully ripe, the whole greenhouse smells like heaven.

Because I don't have much space, I try to optimize every spare inch.

You are going to have SO MUCH FUN!!!
And by the way, I love your title.  For years, my husband would say "You can't grow that in Idaho".  Now he says "My wife can grow ANYTHING!"

[Youcantdothat]

Wow, 3 citrus can fit under a 2' by 4' stretch of lights?!?!?  That's way more compact than I was imagining.  I figured each tree would need a 4' circle to occupy and that they'd be 5-6' tall.  And the yield from them sounds amazing, especially given their stature.  I think my greenhouse just got a bit smaller

So how do they get daylight if you have that many fluorescent lights hovering above them and casting shade? 

As for the pineapples, I'm planning on a row of water barrels on the North wall of the greenhouse and I could possibly put one pineapple in a pot on each barrel.  Then they'd be up higher and be less likely to poke me.

As a side note, I'll also fill up the greenhouse with "normal" veggies like tomatoes, peppers, lettuce, kale, etc so I can have them year-round as well.

I can't wait to put a "Grown in Wisconsin" sticker on my bananas and bring them to the winter farmers market.  I'm guessing I can charge a premium

I'm glad you're growing all this stuff in Idaho, it gives me hope.  Are you in Northern or Southern Idaho?  Just curious about your day lengths. 

[Daintree]

I am in Southwest Idaho (latitude is 43° 36' 49" N).  I don't use the lights in the summer, and because in the winter the sun is lower, the light comes in at an angle so no shade is really cast by the light fixtures anyway. Don't know where in Wisconsin you are, but you are probably a bit north of us.

Yeah, I just have no room for full-sized citrus trees. I buy my citrus in pots, and they come grafted onto dwarfing rootstock anyway (except the finger lime), so it is a piece of cake. The big problem with small citrus trees isn't that they don't flower profusely, it's that the little branches sometimes can't support all the fruit.  So I do get some fruit drop.  If I had bigger trees, I would probably have way more fruit on one tree.  But I only have one of each type of tree, and I like a lot of variety.  So I would rather have 9 different kinds of citrus and slightly fewer fruits, than one big old orange tree.

I have a couple of heirloom tomato plants that I bring in every year, so I love having tomatoes year-round. But they are about 5 or 6 years old now, so I think I will replace them in the spring.  But after this long, I sort of get attached to them...

Haven't had much luck with kale etc in the greenhouse, since it likes it cooler than the tropical house, and I have no room in the citrus house. 

When you divide your greenhouse, make sure you can totally close off the cooler areas.  I have found that if I leave the door open between the two houses, I sometimes can't keep the tropical house warm enough.  I have a door and two 16inch screened windows between the two, so I can control airflow really well.  It got down to -9 last night, and if I had left any of the windows open between the two houses, it would have gotten too cold in the "tropics".

[Youcantdothat]

I'm at 45 degrees N so I'm just barely North of you.  I see, so the lights must be a bit higher off the plants than I was imagining. 

I spent more time outside watching the sun today.  By cutting down a few trees I can get full sun from 10 till 2.  From 2 till 3 there are just two distant pine tree trunks who's shade will pass across the greenhouse.  I could get sun from 9-10 but it would require cutting down the nicest, prettiest maple tree in our backyard.  At least it's deciduous and lets some sun through.

Sorry for the novice questions, but if a dwarf citrus can pump out 25 lemons, how many does a full sized one produce and how big does it get?  Is there a size that is about 6-8 feet tall (semi-dwarf?) and how productive are they? 

5 year old tomatoes?  That's awesome!  I knew peppers could get old but I didn't know for sure that tomatoes could.  Good point on the cool weather stuff (kale, etc).  I'll have to put them on the citrus side.

So what happens if the citrus is warmer in the winter?  If I can keep the whole greenhouse up in the tropical temps will it harm the citrus?

[coyote]

It's great to see a fellow Wisconsinite trying to grow some tropical fruit up here. I don't have a greenhouse, but I've been plugging away the last 4 years or so trying to grow stuff indoors. 

I would agree winter light is going to be one of your biggest issues.  I think with a greenhouse you'll be able to grow lots of great citrus and keep almost anything happy vegetation wise, but you might have a hard time coaxing fruit out of things like the mangoes.  Not that you shouldn't try, you totally should, but I would highly recommend growing sub-tropical fruit (like guavas, loquats, natal plums ect.) and Mediterranean weather plants (like figs and pomegranates) as well. My atemoya and mango trees have really struggled, while some of the things listed above have done very well for me and others in the area.

All that said if there's anything you really want to grow you should, I haven't let it stop me from trying to grow everything under the sun (: and you can count me as one of the people cheering you and your plants to success in our less then tropical state.

[Youcantdothat]

Thanks Coyote!  Now I just need a greenhouse.  I'm still working on the plans and materials.  I'm hoping to build it with lots of cheap materials by scrounging and bartering.  Today I got a good lead on a source of telephone poles so that may be the main structure of the A frame...

I wish I liked any of the sub-tropical or Mediterranean fruits but they aren't often in our grocery sack.  Mangos aren't either but I know I like them.  Citrus is the main one so I'm in good shape for that.

I grew up in Madison and get back there for some holidays.  Is there a source for tropical plants down there?  My local greenhouse has some citrus but I think the selection is a bit limited.

[coyote]

Hey youcan't, unfortunately our local nursery selection is mostly limited to ornamental tropical plants and is only slightly better then when I lived up north. Some will order stuff for you on request which is on option if you don't want to hassle with problems due to shipping, but the cost usually ends up being about the same.  I mail order most of my stuff which I've kept mostly to seeds to keep my costs down.  With a greenhouse though I would recommend getting grafted plants to insure you're getting quality plants and giving yourself the best chances for good fruit.  Looking forward to how your greenhouse comes along...keep us updated.

[Youcantdothat]

Thanks Coyote, I'll just go mail order then.  And grafted does sound like the way to go.

For anyone still following this thread, I'm still hoping for an answer to the following:

Sorry for the novice questions, but if a dwarf citrus can pump out 25 lemons, how many does a full sized one produce and how big does it get?  Is there a size that is about 6-8 feet tall (semi-dwarf?) and how productive are they? 

So what happens if the citrus is warmer in the winter?  If I can keep the whole greenhouse up in the tropical temps will it harm the citrus?

Thanks!!!

[stfrancis]

Being up north really limits the time frame that you can grow anything, let alone tropical fruits, if it is even possible.  Indoors is the way to go for sure.  There are several different methods of doing this, from the simple and affordable to the very complex and expensive.  I have had good success with a small section in my basement with LED grow lighting.  There are several different types of LEDs to go with, some you can get at your local hardware store which is more affordable all the way up to very powerful but more expensive LED lighting specifically made for growing plants. 

Here is a guide that makes it a little easier to pick one out:

http://www.ledgrowlightswarehouse.com/blog/how-to-choose-a-led-grow-light

Hope this helps.

[forumfool]

Nice bump. Curious to hear if the project has broke ground.

Another thing to consider to help regulate temperature is digging down into the ground. There is a greenhouse somewhere in Montana that uses no energy with the exception of low-grade geothermal. I believe it's dug 6-8 down. Actually just looked up a clip of it:

https://www.youtube.com/watch?v=vMJafO-yeKw

Then there is this guy growing bananas in Oklahoma with just digging down a few feet.

http://www.greenfingardens.com/p/semi-pit-tunnel-greenhouse.html

[Daintree]

So what happens if the citrus is warmer in the winter?  If I can keep the whole greenhouse up in the tropical temps will it harm the citrus?

I think that citrus need to be stressed either by drought or cool weather to bloom and be healthy.  I did kill my first few citrus when I had them in the tropical house.  Since setting up the citrus house (the opposite end of the greenhouse from the furnace, nearest the door), they stay much cooler in the winter and are quite happy!