I purchase Peter' 25-5-15 W/Trace Minerals all the time, it is their product number 77990. 25-5-15 is sold in 25-lbs. plastic bags. I normally buy 50-lbs. at a time. The link below shows the fertilizer formulations sold by The Peters Company, under their Jack's Professional Label. You will find 25-5-15 on page three (the 17th fertilizer formulation down from the top).

http://www.jacksprofessional.com/products.pdf

Millet (967-)

well i didn't knew that , I was searching on scotts dot com pages

thanks again

Later Edit , it seems that only in US is to be found ....outside is just Peters and there is no such ratio on any product

Keep searching

...and the closest i got is Universol 23-6-10 (4.6+1.2+2 ratio) I say close enough



Download universol 23+6+10.PDF data sheet

That is close enough.

Millet,

For the Peters 25-5-15, how often can/should it be applied? The recommended 250ppm yields 0.8tsp/gallon. Is that every water or every 2 weeks? I can't find any details on the pictures of its packaging material.

Also, I'd love to read any links you have to research articles that describe the 5-1-3 uptake of citrus.

I do also wonder about the question that is being asked -- citrus do not respond to reduced N/increased P ratio for blooming? They uptake a constant 5-1-3 during the entire growing season?

I know many growers will drought stress to trigger a bloom, but I've not read much about modifying the NPK ratio as you do in deco plants.

TIA

Here is a link for citrus nutrition from New Zeland--but it is for inground trees:
http://www.hortnet.co.nz/publications/guides/fertmanual/citrus.htm

CF4, the frequency of fertilizing your container trees, depends all the amount of nutrition applied with each application. When Citrus Joe and I were visiting the Citrus Clonal Protection Program (CCPP) at the University of California @ Riverside, they fertilized their container trees at 300 PPM N with every watering. Such a heavy application surprised us. Presently, I am fertilizing at 200 PPM N with every watering. In the past I have followed UCR's 300 PPM-N with every watering, and the tree produced an amazing amount of growth, but after 6 months or so, I back off to the present 200 PPM rate. In the text book CITRUS (The genus Citrus) by Giovanni Dugo & Angelo Di Giacomo, they detail their finding of the fertilizer up take by citrus trees growing in groves in Mediterranean countries. Here is what they found......" Loss of minerals varies in relation to the amount of production, soil, climate, agricultural practices. As an approximate estimation, a yearly loss (up take from the soil) of the main elements per hectare, in a mature orchard producing 30 tons of fruit, is as follows: N = 180-220 kg; P20 = 30 - 40 kg; K20 = 90 -120 kg. These are the amounts of fertilizer elements per hectare that must be replaced by fertilizing where there is a satisfactory presence of elements in leaves. These amounts have to be increased to correct for deficiencies and leaching. Fertilizers must be chosen according to their replacing minerals and their ratio. The ratio 5(N): 1(P20): 3(K20) is the ratio of the main elements lost from a citrus orchard. Fertilizer must respect this ratio when the mineral content in the leaves is satisfactory". ....

As to your question concerning if citrus respond to reduced N and increased P at blooming, the authors, do not proclaim this anywhere in their work. However, if anything,I would think it would be the opposite. It would be an additional amount of nitrogen, and not phosphorous to produce a beneficial response to blooming. It is the additional amount of Nitrogen that is given to a citrus tree through foliar sprays, that increase the quantity of fruit set (ie. reduce the amount of fruitlet drop). In another study, applying a 2 percent Potassium nitrate spray mediately after flowering, and a second 2 percent foliar spray 45 days later, has been found to enhance fruit set by 20 percent, and to increase the amount of fruit reaching sizes of 2.75 to 3 inches diameter by 38 percent. - Millet (962-)

5/29/2010

Hi ...

" Happy Memorial Day." A thought can I use
Tomato Food 18-18-21 for my Citrus ?

Cheers...Joe...

Thanks for the various responses. Interesting.

As far as triggering blooms, it was more like decreasing N, rather than increasing P. The folks in the GW Container forum preach that you should never have more P than K, so "blooming" formulations where the P is crazy (like 10-50-10 or similar) is a complete waste of the P nutrients as it won't absorb in excess of the K value. Their philosophy is to keep all containers close to the 3-1-2 ratio but at the right time, you reduce N, such as 1-1-2 or 1-2-2, and your plant responds with a stronger bloom . However, that discussion was about decorative plants.

In citrus, excessive blooms do not promise abundant fruit (witness a stressful WLD triggering excessive blooms when it warms up -->no fruit yields). Your statement confirms what I've witnessed: Increased N (but not beyond fert burn threshold) will trigger larger growth flushes, thereby creating more blooms and retaining enough for a larger crop (for an otherwise healthy tree under the right conditions of course).

Thanks again.

I have seen the benefits of repeated foliar sprays of KNO3 and increased fruit set. I have noticed small fruitlets that are on the border of turning yellow--going to green after repeated sprays of 1-2% KNO3. I have had near 50% set on my Ponkan (20+ fruit out of 40+ flowers) and I am sure that the foliar spray helped do that.

As for fertilizer, for inground citrus in this area, leaching is a major factor--even for container plants that are outside. That is the reason I apply fertilizer monthly from Feb to Sept. However, P binds to soil--even our sandy soil and does not leach nearly as bad as N and K. Since FL has had manufacturers reduce P in fertilizer, I have been applying 10-0-10 for most applications. I do apply a balanced fertilizer with P at least once a yr.

Different soils and environmental conditions require adjustment to citrus nutrition applications, but knowing what nutrition ratio citrus trees use and loose thru fruit harvest is the basis for that application.