Room temp and light

Discussion in 'Citrus' started by aesir22, Oct 5, 2008.

  1. aesir22

    aesir22 Active Member

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    Hi all,

    Just a quick question. The heating in my house is set to come on at about 7am til 9am and again at about 6pm til about 10pm. This is all during the winter. The house doesn't go below the 55.4F during the day - stays in the 60's I would say, but during the night it probably dips between 50F-55F.

    Will this affect the leaves on my citrus? The room will be in the high 60's when the sun comes up here in England, so I shouldn't have to worry about WLD should I?

    I am going to try and keep my citrus in the south facing window they've been enjoying this year over winter, but if it causes problems I will move them either into the garage (though it does get really cold around here - below freezing very often through the winter) or in a north facing room that does not get heated at any point during the year.

    Can anyone think of cheap ways to heat pots? I can't find a decent heat mat over here that I can afford to buy and maintain and I'm not wanting to wrap christmas lights around the pots (the cat will most definitely definitely attack them - our xmas tree never makes it through the season!)

    I have bamboo blinds in the south facing room. When they are down, they cut the light in the room in half. If I do start to experience the dreaded leaf drop, would closing the blind be any use? I am slightly hesitant putting them in the north facing room as my stepdad is in and out of there every other day storing tools and loads of other stuff. He is bound to knock one over or drop something on one of them!

    Any help appreciated! This is my first winter with citrus and am hoping it goes smoothly :)

    Dan
     
  2. frankmass

    frankmass Member

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    Hi
    I never had much luck keeping citrus healthy in the winter, dispite lot of hardwork. Bugs and WLD. I beleive that the humidity plans an important role also. This year some of my citrus go the most basement

    Frank
     
  3. skeeterbug

    skeeterbug Active Member

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    You only have to worry about WLD if the trees are exposed to direct sun while the roots are cold--if your house is going down into the 50's at night you probably will have cold roots--soil does not heat up fast and is often cooler than the room due to evaporation and other factors.

    Like Frank said--the basement is an option--cool dark and very little water--or warm and sunny, but cold and sunny is bad news.
     
  4. aesir22

    aesir22 Active Member

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    lol you don't find many houses in the UK with basements nowdays unfortunately. I had considered the garage but it gets below freezing most nights in there. I have an unheated, north facing room that stays cool with little light. I think I will have to see how things fare as time goes on and make decisions about moving them if and when I have to
     
  5. Millet

    Millet Well-Known Member 10 Years

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    Moving your tree into a cool north facing room should do well. This procedure has been tested many times , normally only a few leaves are dropped by the tree. It is the ratio of temperature to light that causes WLD. Citrus stop root growth and root function if the soil temperature drops below 12.5 C (54.5 F). Leaf activity is greatly reduced if the temperatures is dropped to below 18 C (64 F). Leaf activity means the full process of water evaporation for leaf surface cooling, energy transformation (photosynthesis) and starch reduction for building amino acids and other compounds for forcing plant growth and cell development. Citrus control its leaf temperature by evaporating water from the leaf blade. Therefore if the soil temperature is reduced and the leaf temperature is reduced and kept to below 18C (64 F) WLD is not much of a problem. Remember if a citrus tree is placed in a cold room, but still receives direct sun light, leaf surface temperatures can easily raise to unacceptable temperatures that can cause WLD But under no conditions should a citrus tree be subject to freezing temperatures. - Millet
     
  6. skeeterbug

    skeeterbug Active Member

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    Temperature here is quite variable in winter--not uncommon to have lows in the upper 20s (-2 to 3 C) or highs pushing upper 70s (25C) any day in the middle of winter. I have 12-15 seedlings that are about 2 yrs old in containers. They stay outside except when it drops below freezing. The first winter, I would see significant wilting early in the morning when lows were in the low 60s or lower, so I moved them into my shop at night and back outside after it warmed up. During the following summer I put a shade cloth over them because of our scorching hot sun--I left the shade cloth up as we got into winter and I noticed that I was not seeing the wilting in the morning sun as the temps dropped into the 50s or even the 40s, so I left them outside except for nights that were below freezing (Key limes I brought in at 40).

    Since we have many days that are in the 70s and since my container are fertilized with slow release fertilizer, many continued to flush through last winter. The shade cloth prevents the leaves from overheating when the cooling system is not working (when cold), but allows enough sun for sustained growth when it is warm enough. The tiny spots of direct light that hit the leaf are too small and move enough to prevent overheating, but still allow maximum photosynthesis.
     
    Last edited: Oct 6, 2008
  7. Millet

    Millet Well-Known Member 10 Years

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    Following up on Skeet's excellent post. When I notice a tree starting to drop a few leaves from WLD I quickly place a common bed sheet between the tree and the sun. The leaf drop almost always stops. After bright, sunny mid-winter days, more leaves are shed than after longer periods of less bright light. - Millet
     
  8. frankmass

    frankmass Member

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    Does humidity come into play with wld?
     
  9. Millet

    Millet Well-Known Member 10 Years

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    Many things come into play with WLD. Irrigation during wintertime is a recommended practice to slow down WLD. Irrigation with warm water 25-32 C (77-90F) supports the root function, even the water uptake, so WLD will slow down. Irrigation reduces the plant stress during cold winter time and is therefore recommended. Keeping the trees in a room with high humidity seems also to slow down WLD, but cannot prevent it. Also a place more in the shade, to minimize leaf activity, slows down WLD. Keeping the root temperature below 18 C (64F), but at or above 15 C (59 F) seems to work best for stopping WLD. The plant functions are minimized, but water and nutrient uptake for leaf activity is high enough to support the breathing process and leaf surface cooling by water evaporation.

    A mild winter chlorosis (yellow veins, dull green leaves and sometimes weaker growth) may develop, but this will disappear in spring with rising temperatures. - Millet
     

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