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“Rootblast” versus real fertilizer
List over metals in fertilizers |
Washington standards for metals in fertilizer in ppm |
"Rootblast" NPK 2*1*2 |
"Nutricote Total" slow release fertilizer NPK 13*13*13 |
As (arsenic) |
5 |
2.19 |
1.4 |
Cd (cadmium) |
1 |
2.4 |
<0.014 |
Co (cobalt) |
--- (plants nutrient?) |
3.5 |
<0.028 |
Hg (mercury) |
0.2 |
0.3 |
<0.021 |
Mo (molybdenum) |
--- (plants nutrient) |
6 |
280 (plants nutrient) |
Ni (nickel) |
--- |
9 |
7 |
Pb (lead) |
5 |
49 |
<0.28 |
Se (selenium) |
1 (important for animal and human health) |
1 |
<0.28 |
Zn (zinc) |
--- |
1 |
220 (plants nutrient) |
Some of the metals in “Rootblast” are higher than the accepted (WS ppm.) value in fert. Those can still be accepted (WS rate per Ha) by using a lower recommended rate.
To me “Rootblast” seems to be a waste product sold as a fertilizer!
Price New Zealand:
| Fertilizer | Measure | Price | Price per kg |
| "Rootblast" | 340g | $19.95 | $60 |
| Nutricote | 25kg/270 days | $180 | $7.20 |
| Osmocote | 1kg | $34.90 | $34.90 |
I did some comparison trials and found no better growth with Rootblast
than with Nutricote. Trials were done with small plants and larger 2 years when potted
up.
The 2 years show some slowing down in growth after 2 months when using Rootblast compared to the Nutricote. On the small plants none of the ones with
Rootblast are larger than the ones grown with Nutricote.
The difference seen in the pics in the Rootblast advertizing may be from plants grown without any fertilizer and Rootblast, and not by comparing fertilizer with Rootblast.
The advertising reads “All Natural & Hormone Free” but I have never encountered any
hormones in any dry fertilizer. In my opinion, it is a waste of good money to use “Rootblast” and with the high levels
of lead, mercury and cadmium, I would be worried using this in my vege garden.
Summer feeding:
Nitrophoska Blue Extra or Perfect, tomato fertilizer (or similar chloride free complete fertilizer). Chlorinated (muriated) fertilizer make woody plants more prone to mildew!
