Hi, We live in Basle switzerland. We have a lemon tree which suffered greatly last winter: we left it out covered and installed a 40 watt light bulb at the foot. It worked quite well in spite of a long and cold winter (-15C) unhappily we did not dare water it. It came out looking rather sorry but we managed to have it recover by June: new leaves, new flowers too many fruits which luckily fell. We started giving it fertiliser for citrus trees once a week from the end of June onward, and watered it every day according to the advice of the local tree and flower store. Some leaves new and old started turning yellow, so we gave it iron twice. The leaves continued to turn yellow. We got new advice: water less often and fertilize only once a month (not what is written on the fertilizer bottle) Nothing seems to help and we see winter approaching with some misgivings... Photos of the leaves can be found at: http://homepage.hispeed.ch/lionel.lecoq/lemon/DSC_0457.JPG http://homepage.hispeed.ch/lionel.lecoq/lemon/DSC_0458.JPG http://homepage.hispeed.ch/lionel.lecoq/lemon/DSC_0459.JPG http://homepage.hispeed.ch/lionel.lecoq/lemon/DSC_0460.JPG Thanks for any help you can give us... Lionel
I don't mean to be negative, but when you purchase a citrus tree, you have the obligation to insure that it is give the proper care. Although it is not a human, it is a living plant. You should have never ever placed your citrus tree out side suffering under a Basle Switzerland winter. How many citrus trees do you see growing outdoors in Basle - probably none? My guess is that in Switzerland, it must be almost impossible to obtain anything close to good information on how to properly care for a citrus tree. The long open wound on the branch probably was caused by the cold temperature. Your tree looks in fair condition, but quite under nourished. Before I can give some type of intelligent instructions, I need to know the EXACT fertilizer formula you are using, including ALL the trace elements in the fertilizer, and how much you add with each fertilizing. Also what is the growth medium (potting soil) that the tree is growing in, and how long has the tree been planted in this medium? - Millet (1,198-)
Thank you very much for your answer. To the first point: In Tessin the southern part of Switzerland they grow oranges and lemons... It is however warmer than here (the Alps are in between, it makes a difference) The tree was a gift from students to my wife (we do not believe in having non local trees for the very reason you mention). It is rather large i.e. no way to take it in without breaking one's back. There are actually more than a few warm climate trees growing around here. Even some palm trees survive amiably the winter (with temperature down to -25 C when it's bad) when packaged in special cloth. This is what we did with the lemon tree. We added the 40W light bulb and it worked quite well but for the fact that we did not dare water it for months (ignorance...) It took it 3 months of constant care until it recovered sporting nice new green leaves, flowers etc.. We only started fertilizing it end of June in order not to burn the new leaves. If we can solve the yellow leaves problem, I am quite sure that it will get well through the winter. This time we will water it regularly. The fertilizer we use is a "citrus fertilizer" brand is Plantania (I doubt this will say much to you). One is suposed to use it once a week. formula 1.7% ammonium nitrogen (I am attempting to translate from German) 2.3% nitrate nitrogen (???) 5.8% carbamid nitrogen 4% phosphate (P2O5) 6% potassium oxyde (K2O) 0.01% Bor 0.018% molybden everything below is declared as Chelat from EDTA(?) 0.009% copper 0.034% iron 0.018% zinc One dilutes it 1/300. We prepare 5 liters but stop watering when water starts coming out at the bottom I gave it twice an iron fertilizer 2% iron in chelat form 3% manganese 6% magnesium I assume these are the diluted concentrations (it is in powder form), there also we water until water starts coming out at the bottom We got the tree a year and a half ago, replanted in a larger container (32 liters) adding "normal" earth to the earth it came with. Thanks again for your help Lionel
Your fertilizer is basically a 10-4-6 formula with trace minerals. Carbamid nitrogen in English is Urea nitrogen (not the best for citrus). The fact that the potassium is in an oxide form is also not the best, but I guess it will have to do. Citrus trees always absorb nutrients through their roots in the ratio of 5-1-3. In other words, for every 5 parts of nitrogen the tree's root system absorbs, it will always absorb only 1 part phosphorous and 5 parts potassium, plus trace elements. Therefore, the best type of fertilizer would have a formula something like 25-5-15 w/trace minerals. Unfortunately, there is a problem with fertilizing and the time of year. It is now October, and if you start fertilizing heavy the tree will start to grow new flushes of tender new leaves, which will be easily damaged by cold weather. By the way, new young citrus leaves will not be damaged by fertilizing, in fact the tree actually requires a lot of nutrition during the new growth period. If the tree was kept indoors in the warmth, fertilizing would not be a problem. So fertilize once or twice before you wrap the tree for winter if you plan to leave the tree outdoors. Citrus are HEAVY feeders, requiring a lot of nutrition. You should fertilize your tree at 300 PPM (parts per million) nitrogen. With your fertilizer being only 9.8 percent nitrogen you will need to dissolve 3 grams of your fertilizer per liter in order to obtain a 300 PPM nitrogen level. Fertilize the tree once every two weeks trough out the spring and summer months. Also, as your fertilizer does not supply magnesium, you will need to apply magnesium (Epsom Salts) to the soil once ever 3 months. Dissolve 1 tablespoon of Epsom Salts in a gallon (3.78 l) of WARM water, and apply the cooled solution to the tree's root system. When ever you water or fertilize your tree, ALWAYS apply enough liquid to the surface of the soil so that AT LEAST 10 percent drains out the bottom, this insures that a toxic level of soluble salts does not build up in the root zone. Looking at your trees leaves, I can already see some damage from high levels of soluble salts. Growing a containerized tree in actual dirt (soil) is A TERRIBLE medium to use. Use the search function on this forum supplying words like CHC, Coconut Husk Chips, Bark, and you will be supplied with a lot of good information on the proper type of growth medium (potting soil) you should be using. With dirt as the medium, no wonder the tree is to heavy to move in and out of the house. If you need any further information feel free to ask. The very best to you and this tree. - Millet (1,197-)
Thanks again, actually as far as the soil is concerned my wife just reminded me that we did not repot it, i.e. it is in the medium it came with. I hope that the supplier used the right type of medium. I'll keep your advice in mind for the time we will have to repot the tree. I am going to look for a better fertilizer. Your advice is precious threre. As far as iron is concerned I could use a different product: pellets of 5.5% iron in form of EDDHA-Chelat (brand name is Sequestrene) it works well with roses and hydrangea, I did not dare use it with a container tree because of the difficulty to judge the quantity, I doubt too much iron is good for the soil. best regards Lionel
