I have some random fertilizers that I got from military people moving away from the nearby base. They are granular 15-10-15 and 10-5-15.
Can I use these on peach? I have four newly planted 3 and 2 year old trees that were in pots, and three established trees about 5 years old
A good choice for peach, esp. after harvest.
Good for early Spring also?
Those are peculiar formulation numbers…but no problem using it so long as you don’t over-apply it.
Sorry, didn’t realize you are in Holland/Netherlands.
My French isn’t much, but I can read the label. Looks like good stuff to me. (Just not a combination I’ve seen in the USA).
5-10-15 or 15-15-15 I’ve used before. Just don’t apply too much.
My last name is Holland 
the label is in Italian
The 5-10-15 is good pre-bloom.
OK…at least I didn’t think it read in Dutch! lol
Italian, French, German, Spanish…enough related to English I got the NPK and trace minerals figured.
I do enjoy perspectives from other portions of the globe. Thanks.
If it is European, the P & K value is likely different. The U.S. traditionally expresses it as %P2O5-K2O, and Europe uses %P-K.
The 15-10-15 would convert to 15-23-18 in U.S. The 10-5-15 would convert to 10-11.5-18.
The label appears to list percentages of oxides by weight.
I noticed the 15-10-15 has 4% N nitrate and 11% N ammonia, while the 10-5-15 has 2% organic N and 8% Urea N.
Any real difference between the sources of N?
The nitrate is good to have in the mix for pit fruit and several others depending on origin, but not for some fruits especially blueberries and most of the Vacciniums.
Since it is there, I’d probably use it but commercial peach fertilizers usually have double the N to K. P tends not to matter as deficiencies seem to be quite rare due to mycorrhizal relationships.
Anyone using wood mulch should probably avoid any fertilizer with substantial k for bearing apple trees. A lot of that will come form the mulch and too much can inhibit C absorption.
My main goto for mulched peach trees is coated 90-day urea. It is important to keep peach trees quite vigorous and generating new wood.
Perhaps in your climate. Peach trees have plenty of vigor in milder locations where Hugh and I live.
In the spring, using liquid fertilizers is better. It releases faster which provides external supplement NPK to the bloom and fruit set.
I also have an unopened bottle of liquid citrus fertilizer…it’s something like NPK 8/9/8 with a tiny amount of iron, manganese and zinc. I don’t see any difference compared to stuff not specifically for citrus so I assume it would be ok
Not necessarily, without N supplementation. However, you may be right that CA growers need less generally than East coast growers, but I’d like you to show me information that supports a milder climate being the reason… what is that based on? Please accept this question in the spirit in which it is made… genuine curiosity.
You’ve already indirectly taught me that peach growers in the west tend to use less fertilizer than those in the east… but he west is also drier, with a tendency of deeper soils, both of which could generally affect N requirements.
factor
Peach and Nectarine Production
Page 3
Fertilization
Based on a survey conducted by the USDA
in 2009, California growers applied an annual
average of 54 lbs N/acre to peaches and 46 lbs
N/acre to nectarines. In the same year, the
average phosphate (P2O5) application was 25
lbs/acre for both peaches and nectarines, and
potassium (K2O) applications averaged 30 and
37 lbs/acre respectively [8]. For both peaches
and nectarines, average fertilizer applications
have decreased over the past few decades. This
may be in part because of the adoption of
fertigation, which delivers fertilizer more
efficiently than older methods, as well as better
understanding about the negative effects of
over-fertilization.
And here are the recs for PA Mar 2, 2021The nitrogen needs of peach trees will vary with many factors, but typically trees should receive 50 to 100 lbs of N per acre per year, depending on soil, pruning severity, and crop load. Stored N is insufficient to maintain commercial crops, so annual N applications are required to maintain tissue N status.
I should also say that UC Davis suggests a good deal of supplementary P is used which contradicts my statement on that. I do not produce fruit commercially, but i manage a lot of orchards and have not once, in 30 years I’ve been doing this, observed a P deficiency. If anyone has info on this, I’d be interested as well.
This is doable. The timing is important and has to make sure the fertilizer goes to the root zone(not just wet the surface). It must fertilize the tree before top start to grow. Use last year’s the tree start growing date minuses two weeks then you find a date to start fertilizer, a week early is OK too. But if fertilize too late, when the tree already grow, the fertilizer is less effective. This is for liquid fertilizer. If using bagged fertilizer, needs to apply almost a month earlier.
@Richard in some of the threads you recommend applying SulPoMag in fall which is similar to this mineral Langbeinite 0-0-22 + 10% Magnesium and 22% Sulphur.
I presume this will breakdown during the winter and be available for the trees to take up in Spring. I also found Langbeinite is water-soluble means I can put a tablespoon or two in a gallon of water and it dissolves overnight. If I apply it in the fall and our rains will dissolve it in a month will this be still available for plants to take up in the spring,
