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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)




Cd (cadmium)




Co (cobalt)

--- (plants nutrient?)



Hg (mercury)




Mo (molybdenum)

--- (plants nutrient)


280 (plants nutrient)

Ni (nickel)




Pb (lead)




Se (selenium)

1 (important for animal and human health)



Zn (zinc)



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!

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