Citrus is really not all that fussy about fertilizer WHEN planted in the ground. However, for a containerized tree it is a different story. A citrus tree always absorbs nutrients in a 5-1-3 ratio. Therefore, for every 5 parts of nitrogen the roots absorb, they will always absorb only 1 part phosphorus, and 3 parts potassium. The problem with a peat lite fertilizer is the high phosphorus level. Nitrogen and potassium are both quite water soluble, therefore can be flushed or will leach from the growth medium. However, phosphorus does not leach readily where the growth medium's pH is 6.0 or higher. The tree itself, removes very little phosphorus nor does the fruit crop. Therefore the phosphorus levels will continue to rise in the container. When a citrus tree is planted in the ground, excessive amounts of the macronutrients are often merely tolerated by a citrus tree, but ALWAYS results in lower quality of fruit or in the case of nitrogen reduced crop yields. Some people use a 30-10-10 formula, and their trees generally look good, but due to the excessive nitrogen ratio, trees fertilized with 30-10-10 normally produce a much smaller crop than the tree would have produced had the correct fertilizer ratio been used. My recommendation, take it or leave it, is to try to find a fertilizer with a formula as close to a 5-1-3 nutrient ratio as possible. At least locate a formula that does not contain such a high level of phosphorus. - Millet
Scott's has a 13-2-13 Plug Special that would be a lot better formula for a slow release fertilizer. - Millet
Isaac, what else would it be based upon? 5-1-3 is a ratio that has been long known. If you would like to read about it, you can find it in many technical writings concerning citrus. One particularly good source of information can be found in the book , "The Genus Citrus" by Giovanni Dugo and Angelo Di Gacomo. - Millet
Isacc, now that you restated your question, I now understand what you were asking. From your earlier post, I thought you were asking if the 5-1-3 ratio was based on scientific research, which of course it is, that is why I answered what else would it be. I did not mean to be rude. For some reason I seem to aggravate you, I regret that. I was only trying to answer your inquiry, and supply you with further information where you could read more on the subject you inquired about. In the future I think it would be best if I longer respond to any of your threads. I wish you the best. - Millet
Millet ..5-1-3 ratio is based on scientific research as you say. Can you provide us as members with this scientific research in using the 5-1-3 ratio. how about the soil mix, the citrus tree. the growing zone, and Temp. It's all got to do with 5-1-3 ratio. I don't think so. it's got to do with the soil, tree.and climate. Oh ..perhaps you grow citrus in containers, is it the same. The 5-1-3 ratio uptake for citrus is the same, NO we all need to reach out to each other with a helping hand. Not as a leader but as a friend.
Right-o. Closing thread while I sort this out. Too bad this happened while I was busy with another project, otherwise I would have stopped this sooner.
