cold hardy citrus in full soil in greenhouse

Discussion in 'Citrus' started by Incubator, Feb 21, 2021.

  1. Incubator

    Incubator New Member

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    I'm getting a Kumquat and shikuwasa soon because they're cold hardy for our winters and I don't have to worry too much about the plant dying from the cold (though I will protect it) but I prefer to plant these in full soil, not in containers in the greenhouse (because that's where I can plant whatever i want).
    My question is, will such citrus survive warmer summers? Often I have potted citrus that get dried out leaves when the sun shines and the temperature rises above 32 °C, even during heat waves inside the greenhouse it gets to 50 °C.
    The greenhouse is 4.5m long, 3m wide and 2.7m high, the sunny side has a shade cloth because the whole thing gets plenty of sun light anyway and has 4 windows and a double door. Naturally I open up everything completely when temps rise above 25 °C but I just want to make sure that I'm not making a stupid decision of planting these in the greenhouse.
    As to why I want them in full soil:
    - I prefer to limit the citrus in containers
    - Full soil has better moisture management and root development for long term
    - no need to hassle with giant containers in the later phases.

    I cannot plant them outside the greenhouse because we get too much rain and in winter I want to protect them a bit more from the cold, because they develop fruit in the months we get frost.
    Our winter temperatures usually float around -4 to -7°C but last winter we had an exceptionally cold one of -10°C.
    I was going to cover them up with a fleece cover regardless but still, the summer is worrying me more.
    I do not have the accommodation or space to place ventilation systems in the greenhouse. Only the 4 windows and double door to open up.
    Is it possible to plant those citrus in the soil in my greenhouse and how do I keep them from drying out given the above mentioned conditions?
    Or is it completely impossible this way? If so I can let them stay in the greenhouse (fully wrapped in) in winter and during the spring/summer etc I can put them outside.
     
  2. growest

    growest Active Member 10 Years

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    I've had a Meyer lemon in my greenhouse for many years now. Our climate here in S.W. British Columbia sounds very similar to yours.
    As you've mentioned, growing in the ground solves a number of problems, especially allowing the tree to grow much larger with a bigger root run than possible with most any container. Also the ground stays much more frost free than the contents of a container, even inside the minimally heated greenhouse.
    If winter cold is not the limiting factor for your area...you are right to worry about summer heat. My greenhouse is bigger than yours, but does have poly sides that can roll up for venting. This keeps my temperatures in the low 30's most summer days, maybe 40C during a hot spell here. I can't quite imagine the amount of air movement you get with your door and windows...but I find there is some leaf scorch happening when things get over about 40C in mine. I suspect that being in the ground rather than a container at these temperatures is an advantage, since the roots continue to operate well in the comparatively cool ground. Keeping up with irrigation is obviously also a priority, but again the ground is far easier to manage moisture than any container in the greenhouse!
    The meyer lemon gives us hundreds of lemons in an average year. Most of them ripen in fall and winter...so planting in the greenhouse has been really crucial. Most of those fruit would not survive our wet and freezing conditions to produce a useable crop, except with the help of the poly greenhouse cover and a network of inground hoses, circulating warm water, that keep the ground mostly above freezing.
     
  3. Incubator

    Incubator New Member

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    Thanks for your feedback, in my case I do fear the fact my greenhouse is smaller , the heat buildup in summer will be deadly, we had 50°C inside the greenhouse a few summers and it killed a limequat in a container If the greenhouse were bigger it would be easier to get a better temperature.
    Hence I decided to put them in containers and place them outside in summer, right now they're happily growing in my greenhouse but in May I have to move them out.
    The risk of the plant losing foliage in a hot summer would have been too painful.
     
  4. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    I wonder if a large box fan would be enough to provide sufficient air circulation. What if you were to place the fan near the entrance with windows at the far end of the greenhouse open? Would the tunnel effect be enough to draw air through for cooling?
     
    Last edited: Mar 23, 2021
  5. Incubator

    Incubator New Member

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    If I had the possibility to get electricity there yes, but there is no power there and the other members of this family do not want to invest in this. They think I'm beyond obsessed with putting a fan in there, so I don't.
     
  6. Will B

    Will B Active Member

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    Maybe try a solar fan? It will have power when needed the most, on hot sunny days. Also, consider some automatic vents. I have the automatic vents in a couple of my greenhouses and they work very well. They automatically open when it gets hot: Heat-Activated Window Opener - Lee Valley Tools
     
  7. SoCal2warm

    SoCal2warm Member

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    Temperatures can get extremely hot inside a greenhouse during clear sunny skies, even if it remains cold outside. Citrus are not going to do well at 50 °C. You will have to make sure to vent out the greenhouse. But preferably close the vents at night.

    Due to this problem, the idea of greenhouse may be more complicated and more trouble than it is worth.

    I've also found that warm active growing conditions can make the plants more susceptible to freeze damage. The plants will not be very resistant to cold damage if they are not in a state of dormancy. In some situations I believe keeping them in a greenhouse could even result in more cold damage than they would otherwise suffer outside.

    Well, the other option is to leave the vents open. That will at least protect them from the rain, and help extend the growing season a little bit.
    You might have to forget about fruit hanging on the tree into January.
     
  8. Incubator

    Incubator New Member

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    I was afraid of that, from what I have found in local citrus growers in The netherlands it seems best that I keep them only in the greenhouse during colder periods (november - march) and put them outside.
    They prefer to keep them in the greenhouse until May after the last possible frost (around 15 may we get a few nights that are cold and then its only warm weather) but that is no longer a good idea since newt week we get clear skies , full sun and 21°C for 2 days followed by a colder week and possible -1 °C.
    Since one of my plants is so big it sits in a large container (57 cm diameter, terracotta and pretty heavy) and therefore it's not convenient to move it outside for just those 2 days and back inside for the colder ones so I have to leave it inside the greenhouse until half of May and then I can move them outside.

    But I have already given up on the idea of growing them permanently in a greenhouse, it's indeed too much problems.
     

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