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ย J.R. Peters, Inc is a family business. The company was founded in 1997 and based on 70 years experiens in the growing field. Bob Peters started his Horticultural Services Co in 1947. He tested soil for greenhouse growers and made recommendations on how to produce the best crops. His son Jack Peters is advancing the tradition of Peterโ€™s family quality products and services.ย 

J.R. Peters, Inc has its own in-house testing laboratory that has been providing outstanding analytical services to the horticulture industry for over 70 years. Professional growers, horticultural products manufacturers, and university researchers throughout the world trust us to supply accurate and timely services.

J.R. Peters, Inc also produces specialty fertilizer products for other companies that demonstartes high level of production and reliability of this company.



Latest reviews Show All reviews (10)

Canna_Reaper Apprentice
I think I'll continue to use Jack's. It's a simple 2 part, easy on the wallet, and didn't have any deficiencies during flower.
5 days ago
Wasn't using the specific brand but rather a similar 20-20-20 slow release dry fertilizer. If you are noob like me and on a budget this type of nutrients will do the trick if used with caution not to over do it, especially towards the late and last stages of flowering!
6 days ago
Canna_Reaper Apprentice
Jack's nutrients 2 part was great, simple to use, and didn't show any deficiencies throughout flower.
2 weeks ago
BigNate89 Apprentice
Worked great, created hard and full buds, didn't give me any burn at all either
1 month ago
simps Apprentice
I use it on all my big plants good stuff
2 months ago

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Latest comments


Greetings All: First of all, this nutrient is cost effective aka cheap.

Previously, I was a House n Garden user. Loved my results. Costs...phew!! Came across JR Peters while following other growers (mentors DIY COBs) I saw their results. Started using JR Peters, Jacks 321 formula in coco. Results totally floored me. Another plus to me is that I use Jacks 321 from cutting thru flowering, I water/feed all from the same rez. No measuring amounts for early veg, etc. I prep the rez and feed all from there. Have yet to see any adverse effects. As an additive, I've begun using Mammoth P. Hope this helps.


I use
3.69g/gal of 5-12-26
2.45g/gal of 15-0-0
Plus I add in 220ml of Cal-Mag (my well water is like 70ppm so I need that CalMag)
I donโ€™t change from beginning to end. Same strength all the way through.
My only additive is Terpenez and my stuff gets quite stinky. No cover up in a bag in a bag in a bag.
In my indoor hydroponic ebb and gro setup.
I do this under 6-315watt CMH lights and yield 5 lbs nearly every time.
Airsealed room with 12k worth of mini-split AC and CO2 enriched. I run two rooms like this.