Elemental Vs Oxide Fertiliser NPK Values

[WafflesIceTangerine]

Did anyone else not realise that NPK values are different between US and Aus? I came across this pretty much by chance when trying to find out why tf bunnings nutes all seem to lack P. Apart from waterway worries, one of the reasons looks to be that it is calculated differently in Australia. This is a bit confusing when a lot of the educational info is from the US.

In short, in multiply American P values by 0.4 to get Aus vaules, and K by 0.8.
A much better explanation:
https://gardensuperstore.com.au/oxide-to-elemental-npk-conversion/

Some examples:
here Campbells Diamond Special T listed as 8.2-3.9-32.2 and it also lists the equivalent 8.2-9-38.8
here Nova Peak lists both 0-52-34, and 0-22.7-28.2

With a lot of canna nutes being imported, this can potentially lead to incorrect mixes. Not to pick on you @Goonie Goat but I was reading your growing on a budget thread (amazing btw, thank you) and you have mixed up the values, for Campbells you are using Aus values, and for Nova Peak you are using US values. Now it might not matter perhaps in practice, but this goes to my point that when we are going to the effort of calculating these things accurately, measuring PH, EC etc, we don't want to be way off just because of confusing labelling!

 

[Goonie Goat]

Did anyone else not realise that NPK values are different between US and Aus? I came across this pretty much by chance when trying to find out why tf bunnings nutes all seem to lack P. Apart from waterway worries, one of the reasons looks to be that it is calculated differently in Australia. This is a bit confusing when a lot of the educational info is from the US.

In short, in multiply American P values by 0.4 to get Aus vaules, and K by 0.8.
A much better explanation:
https://gardensuperstore.com.au/oxide-to-elemental-npk-conversion/

Some examples:
here Campbells Diamond Special T listed as 8.2-3.9-32.2 and it also lists the equivalent 8.2-9-38.8
here Nova Peak lists both 0-52-34, and 0-22.7-28.2

With a lot of canna nutes being imported, this can potentially lead to incorrect mixes. Not to pick on you @Goonie Goat but I was reading your growing on a budget thread (amazing btw, thank you) and you have mixed up the values, for Campbells you are using Aus values, and for Nova Peak you are using US values. Now it might not matter perhaps in practice, but this goes to my point that when we are going to the effort of calculating these things accurately, measuring PH, EC etc, we don't want to be way off just because of confusing labelling!

Nice detective work there waffles

The diamond special t did seem suspiciously low in phosphate so it's good to see the real ratios. Although it works fine as is I'll have to change it up a bit, thanks for bringing it to my attention

 

[benn0]

Did anyone else not realise that NPK values are different between US and Aus? I came across this pretty much by chance when trying to find out why tf bunnings nutes all seem to lack P. Apart from waterway worries, one of the reasons looks to be that it is calculated differently in Australia. This is a bit confusing when a lot of the educational info is from the US.

In short, in multiply American P values by 0.4 to get Aus vaules, and K by 0.8.
A much better explanation:
https://gardensuperstore.com.au/oxide-to-elemental-npk-conversion/

Some examples:
here Campbells Diamond Special T listed as 8.2-3.9-32.2 and it also lists the equivalent 8.2-9-38.8
here Nova Peak lists both 0-52-34, and 0-22.7-28.2

With a lot of canna nutes being imported, this can potentially lead to incorrect mixes. Not to pick on you @Goonie Goat but I was reading your growing on a budget thread (amazing btw, thank you) and you have mixed up the values, for Campbells you are using Aus values, and for Nova Peak you are using US values. Now it might not matter perhaps in practice, but this goes to my point that when we are going to the effort of calculating these things accurately, measuring PH, EC etc, we don't want to be way off just because of confusing labelling!

I always thought the low P values where so they could sell the same product in W.A where there are limits on selling such products with P. Explains a lot

Cheers!

 

[Goonie Goat]

Changed the recipe to all Aussie npk ratios, according to Google the Aussie ratio is more accurate than American so fingers crossed its good enough.


Veg is pretty easy numbers to get, happy with 3-1-2 or 2-1-3

Flower is a bit more of a challenge thanks to the odd numbers in special t but still works, just hard to get the Phosphorus up without having either Nitrogen or Potassium skyrocket.

 

[Goonie Goat]

VEG
Special T (8.2-3.9-32) 0.60g/L
CalNit (15.5-0-0) 0.90g/L
MagSulf (0-0-0) 0.25g/L (+0.25g if deficient)
MKP (0-22.7-28.2) 0.25g/L
(Total NPK 10.46-4.58-15.00)

EARLY BLOOM
Special T 0.80g/L
CalNit 0.50g/L
MagSulf 0.25g/L
MKP 0.70g/L
(Total NPK 6.95-9.50-22.67)

RIPENING / LATE FLOWER
Special T 0.20g/L
CalNit 0.20g/L
MagSulf 0.25g/L
MKP 0.70g/L
(Total NPK 4.18-15.15-23.76)

 

[sp4c3]

VEG
Special T (8.2-3.9-32) 0.60g/L
CalNit (15.5-0-0) 0.90g/L
MagSulf (0-0-0) 0.25g/L (+0.25g if deficient)
MKP (0-22.7-28.2) 0.25g/L
(Total NPK 10.46-4.58-15.00)

EARLY BLOOM
Special T 0.80g/L
CalNit 0.50g/L
MagSulf 0.25g/L
MKP 0.70g/L
(Total NPK 6.95-9.50-22.67)

RIPENING / LATE FLOWER
Special T 0.20g/L
CalNit 0.20g/L
MagSulf 0.25g/L
MKP 0.70g/L
(Total NPK 4.18-15.15-23.76)

ok, so this is the new adjusted formula....i will adjust too.....

 

[Goonie Goat]

ok, so this is the new adjusted formula....i will adjust too.....

It should be good, but you'll probably see some fade happening with the Ripening/Late flower amounts with the lower nitrogen, I'd switch in the last 2-3 weeks of flower