I am currently using Jacks 25-5-15 HPF and Calcinit calcium nitrate 15.5-0-0 (half and half) feeding at 300 ppm N with every deep watering. Curious to know if this is adequate? more/less? I know 300 PPM is fine for containerized citrus but does this also apply to inground? I am using a Dosatron injector to dispense the fertilizer. Also, at what points do you increase or decrease PPM? by month? new growth? flowering? feed through winter? Thanks in advance.
Dan

Fertilization of citrus trees, both the amount applied, and the number of applications per year, for in ground trees is according to a tree's age. If your trees are less than 4 years old, you should not use a fertilizer stronger than 8 percent nitrogen to avoid damaging the young citrus trees with fertilizer burn. Not strictly limited to, but the common fertilizers that are traditionally used for in ground trees are 6-6-6, 8-8-8, and for trees 4 years and older up to 10-10-10.

Millet (702-)

Millet,

I remember reading that the "optimal" ratio is 5-1-3. What are the benefits using balanced fertilizers? I am really curious since was trying to mix "right stuff" for them out of balanced, sulpomag, and ammonium sulfate.

Thank you!

5-1-3 is the "perfect" ratio, as it is the ratio that a citrus tree absorbs nutrition from the soil. Obviously, in cases of over dosage or deficiency of one or ore elements this ratio must be changed to a more appropriate one. I always use such a ratio with container trees. When using a balanced fertilizer such as 6-6-6, 8-8-8 or whatever with a in ground tree, the tree will still absorb nutrients according to this natural ratio. However, due to the leaching of nutrients out of the root system with every irrigation or rain, the root system of in ground trees does not get as out of balanced as can a container, unless a container is flushed out with clean clear water on a scheduled basis. That said, the book "The Genius Citrus", states that a fertilizer with a 5-1-3 ratio should be used even with in ground trees. The author states, " There are many commercial products. 5-1-3 is the ratio of the main elements lost from a citrus orchard, and a fertilizer must be chosen according to the replacing of these minerals and their ratio." However, because of cost, and the ease of locating large quantities of readily available commercial fertilizer in bulk, the use of whatever ratio is used. - Millet

Millet,

Thank you very much for the excellent clarification! I have a bunch of different fertilizers (although in small quantities) like Scotts balanced (either 6 or 8 ), MG 24-8-16 with micro elements, and whatever I mixed from "cheap components" to resemble 5-1-3. Guess, I will experiment with them on my over-planted trifoliate seedlings this summer to see how they respond. Aver all, I do not need 20+ seedlings... Do I?

Thank you again!