NPK - your choice would be?

[AnTTun]

To my surprise, I found out that one chemical company in Croatia manufactures fertilizers of various kinds. And now I'm not sure which one should I buy I decided not to pay attention to additional ingredients but to N-P-K only in effort to narrow down their offer. Whats left is this:
4-6-8
4-5-10
3-6-8
3-7-9

Your choice please?

[iann]

Wrong question. Insufficient information. Does not compute

There is nothing to choose between the NPK numbers. There might be other differences such as trace elements or the detailed makeup of the major nutrients. Or they might just be messing with your head creating five different "consumer products" out of the same basic fertiliser.

[AnTTun]

Doesn't matter which trace elements some fertilizer has in this case , I'll never buy 15-15-15 (for example). I've seen what too much nitrogen does to cacti

[McFarland]

Hi AnTTun, there have been some really excellent journal articles on this subject, when I have more time I will try and track them down for you.

I think one of the main points in some of the articles I saw was that while the N-P-K ratio is important, more important is all the trace elements. I'll try and find more info and write back to you

[AnTTun]

McFarland, too much nitrogen turns cacti into brown squishy mess I wouldn't like it to happen again. Looking forward to any additional info you can provide.

Anyway, here is additional info:

FERTINA C - za cvijeće i ukrasno bilje

NPK 4-6-8+B, Cu, Fe, Zn

Dušik (N) 4 %
Fosfor (P2O5) 6 %
Kalij (K2O) 8 %
Bor (B) 0,01 %
Bakar (Cu) 0,002 %
Željezo (Fe) 0,02 %
Cink (Zn) 0,002 %

FERTINA C - za pelargonije, surfinije i ostale cvjetnice

NPK 4-5-10+B, Fe, Mg

Dušik (N) 4 %
Fosfor (P2O5) 5 %
Kalij (K2O) 10 %
Bor (B) 0,1 %
Željezo (Fe) 0,2 %
Magnezij (MgO) 0,05 %

FERTINA C - za sobno cvijeće i krizanteme

NPK 3-6-8+B, Fe

Dušik (N) 3 %
Fosfor (P2O5) 6 %
Kalij (K2O) 8 %
Bor (B) 0,1 %
Željezo (Fe) 0,2 %

FERTINA V - za voćke

NPK 3-7-9+B, Cu, Fe, Mn, Zn

Dušik (N) 3 %
Fosfor (P2O5) 7 %
Kalij (K2O) 9 %
Bor (B) 0,2 %
Bakar (Cu) 0,002 %
Željezo (Fe) 0,02 %
Mangan (Mn) 0,01 %
Cink (Zn) 0,02 %

[DaveW]

Usually flower or fruit fertilisers lower in nitrogen are recommended for cacti. However one of our old branch members, an ex nurseryman, used to recommend different fertilisers at different times of the year. He claimed cacti when growing rather than flowering required higher nitrogen fertilisers than the flower or fruit ones, just the same as other plants. He used to grow some magnificent plants too.

The question may not be just the fertiliser composition, but the strength you use since cacti grow at a slower rate than other plants. However it may really be a question of how fast they assimilate nutrients rather than the amount of nutrients available in the soil, provided these are not at toxic levels since desert soils are some of the most fertile in the world when given irrigation.

I will leave the chemists to comment on the best composition.

If you search the web you will find many different opinions of fertilisers to use. Obviously the ones that work best are the ones that provides the nutrients your compost lacks, which may not be the same for all growers. If your compost lacks nitrogen then a nitrogenous fertiliser will probably work wonders, just as fertilisers higher in the other two if the soil is lacking those. It's a case of experimenting and finding what works best for your conditions.

http://www.theamateursdigest.com/feeding.htm

http://www.succulent-plant.com/fertiliser.html

http://www.cssainc.org/index.php?option ... Itemid=212

A few quotes for cacti:-

"Fertilizer can be added to every second watering during the summer, with the frequency and concentration of fertilizer being reduced in winter. Either a specially formulated cactus fertilizer can be used, or fertilizer such as 15-15- 30 which includes minor or trace elements."

"As a rule C and S don't require much fertiliser, except certain species (Orchid or Epiphytic cactus) or those overdue for a repot. The Fertiliser must not be high in Nitrogen, otherwise the plant will be "forced" and grow out of character or more seriously be prone to disease or rot and less likely to flower in some species. Cacti will have less pronounced spines. A half to quarter strength Tomato fertiliser is usually a good one to use in the growing season. pH can a big part in availability of nutrients to the plant."

This one for Epiphyllums:-

"WATERING and FERTILISER Root moisture should be available all the year round, but remember to water freely in hot weather. An addition, spraying with water is particularly beneficial in hot weather, to maintain a high humidity. From March onwards water with a low nitrogen, high potash fertiliser such as Cactus or tomato fertiliser. This helps promote flowering.
After flowering change to a high nitrogen fertiliser to promote growth for enhanced flowering the next year."

From all the different compositions recommended it seems our plants are not that fussy provided the fertiliser is not too strong and salts do not build up in the soil. An occasional leaching of the pot to remove them seems to be beneficial.

http://www.ehow.com/how_6454354_leach-p ... lants.html

AnTTun could your "brown squidgy mess" be due to over fertilisation not the incorrect type? Maybe you should leach the pots periodically?

DaveW

[AnTTun]

When I was a 'cactus kid', experienced grower taught me simple rule: N = no, no, P = flowers, K = hardiness

A friend of mine and my humble self decided to test first part and used 15-15-15 fertilizer on few young echinopsis hybrids and few small cereuses. I don't remember exactly which ones they were, but they were domestic ('every household had them') rooted offsets. I guess their tissue got vulnerable because of extra nitrogen and rot. Other cacti, watered at the same time with water only didn't suffer any harm. So, since then I'm quite careful when it comes to nitrogen, maybe for no reason, but still...

[iann]

So you over-fertilised and killed some plants? Seems like you took the wrong lesson from that one ...

I don't know how you can be so sure that trace elements don't matter, but if so then there is no difference between the fertilisers you list. The exact chemicals used might vary but the results would still be very similar.

[lobman]

None of the variations available from the company seem particularly unsuitable to me , but as others have stated , the solubility and trace elements are equally important

I personally see no point in using chemical balances that help to induce flowering until a plant is actually reaching flowering size ,( which in some cases will at least ten years ) and hence use more balanced mixes up to that point ; however when a plant has reached the mature size I apply the higher K fertiliser at the end of the growing season prior to drying off and again in the Spring for the first watering's when the buds are developing . After flowering I use the balanced feed again until the Autumn . In general I find cacti take a while to show any changes of growth relating to anything given to them , a bit like controlling a large ship .

I think that to turn something too mush , the nitrogen must have been many times too strong . If I obtain a batch of pants that are on the yellow side I think nothing of giving them some soluble lawn fertiliser to bring them round to the correct colour green .

[AnTTun]

I have to correct myself: trace elements don't matter for making initial choice between NPK ratios. As my topic said