Hi again,

I found and bought 2 packs of Osmocote fertilizer.I asked them many times if it is 18-6-12 and they approved on phone.Then the fertilizer arrived and surpriseee!!! It is 18-9-10 instead of 18-6-12

Then we checked the stocks and found out that 18-6-12 is not available here and will not be in near future.

So, they are ready to get the fertilizers back or I can keep them as a "better than none" option.

Beside the ratio, it is slowly released just as 18-6-12.

Do you think it will work with a little water soluble N+K support? Here a company produce 25-5-10 water soluble fertilizer.
Watering with this fertilizer or ammonium sulfate and potassium nitrate mix can balance the osmocote, what do you think?

Do you use slowly released and water soluble fertilizers together?

Thanks

the 18-6-12 is like 9-3-6, which is close to 5-1-3 and should be more than good enough, and I wouldn't add anything except for minors. to be perfect, you can balance it with N and K like you planned.

Correcting the osmocote 18-9-10 to adjust into 5-1-3
for each kg of this Osmocote you would need to add 1,29 kg of Ammonium sulfate and 0,77 kg of sulpomag

When properly mixed, the effective raw ratio would be: 14,71- 2,94 - 8,83 which is exactly a 5-1-3 ratio, but beware, the N and the K would have spiked availability during the first watering because of slow release of the original 18-9-10.

Thanks a lot JoeReal,

As I mentioned, 18-6-12 is not available, I need to forget about it.

The problem is, with the first few waterings, I will lose the additional fertilizer.Osmocote will be still there but water soluble fertilizers will be washed away.So I had to add the additional fertilizer in small amounts with each watering.I guess this will be a very complicated calculation.

I have to find out how much amount of Osmocote is released with each watering or time period and I need to balance it

Very, very difficult situation

ok, forget about the difficult question above

How about Osmoform 18-5-13, have you ever used it?

http://www.scottsprofessional.com/en/product/291

Quote:

Ideally suited for container grown nursery stock. It contains a balanced mix of immediately available and slow release nitrogen. The slow release of nitrogen is determined by the growth pattern through the interplay of microbial activity, temperature and substrate humidity.

I will use RootmakerII trays and the seedlings will stay in them around 8-10 weeks and the release time of that Osmoform is exactly 8-10 weeks.The Osmoform can be a good solution.

When I transplant the seedlings to Rootbuilder II quart, I can rearrange the mix and the fertilizer.

I like the idea, what do you think?

The fertilizer ratio is more within the range needed by citruses. High N, low P and moderate K.

Thanks JoeReal,

The NPK ratio is fine, I wonder if a 8-10-weeks-release fertilizer is suitable to start citrus seeds.

I searched the forum and it seems Osmoform is never mentioned before.
It says Osmoform is a topdress fertilizer.And my dictionary doesn't help much, what is a topdress fertilizer?

Btw, in this pdf document, 0,5-2gr/l is recommended in substrate mixing for container nursery stock.

topdress means you apply it on the top of the soil. Usually fertilizers are applied basally before planting, and it is set in bands below the soil, then a follow-up application is usually called a topdress, when the plants are established and you don't want to disturb the roots. For temperate trees that becomes dormant during the winter, you can apply fertilizer into their rootzones, and not on the top, so it is not called topdress application. Citrus have sensitive roots, at best you should apply in just a few inches of the topsoil, but depends if fertilizer is highly soluble or slow release.

It is both recommended as a topdress and substrate mix fertilizer.So when I use it in my peat/perlitte mix in rootmaker trays for the seeds, it will be allright.I will not disturb the roots.

Thanks for the replies JoeReal.

The special importance of Osmocote 18-6-12 is NOT the fertilizer formulation. What is special about 18-6-12 is the manner in which the nutrients are released (rate) of nutrient release. 18-6-12 IS THE ONLY SLOW RELEASE FERTILIZER (NO EXCEPTIONS) that can be blended directly into the germinating medium, or into a medium used for the rooting of cuttings, because of the way that the nutrients are released. 18-6-12 releases its initial nutrients VERY VERY SLOWLY, then as time goes by the release rate gradually increases. This type of release is exactly the type of nutrition that a new germinating seed or a cutting that is being rooted requires. The use of 18-6-12 generates an abundance of extra growth and vitality to the seedling/cutting way beyond the first transplanting into the second year, even though the original 18-6-12 application is completely used up. This is the reason Scott's manufactures this formulation of fertilizer. 18-9-10 is a traditional " more of a rapid release" slow release fertilizer. If you apply 18-9-10 with or without regular water soluble fertilizer added you will kill every seedling and greatly retard or completely stop a cutting from rooting.

Thanks Millet,

In this situation, the only solution is to find a fertilizer supplier who ships to Turkey.
I sent 4-5 emails to some suppliers and waiting for their replies.

Best,