Jack's Nutrients 5-12-26 Part A Fertilizer | 2.2lb

Part A of the Jack's 3-2-1 Hydroponic Feeding System, 5-12-26

A multi-part hydroponic feeding system only works if each component goes into the reservoir in the right order. Jack's Nutrients 5-12-26 Part A Fertilizer is the first component mixed in JR Peters' 3-2-1 system, promoting the growth of leaves and strong roots with purely soluble, available nutrients.

2.2lb, Part A of the 3-2-1 system, mixed first.

Key Features & Benefits

• 5-12-26 ratio, Part A of the Jack's 3-2-1 system — purely soluble and available nutrients for maximum feeding flexibility.
• Promotes leaf and root growth — specific macro, secondary, and micronutrient mixtures for many growing environments.
• Mixed first in the 3-2-1 sequence — manufacturer guidance: Part A first, then Epsom Salt, then Part B last.
• Sold under the CEA-focused Jack's Nutrients brand — sized for greenhouse and indoor controlled-environment production.

Who Should Use This Part A Formula

This fits growers running JR Peters' Jack's 3-2-1 hydroponic feeding system, or anyone who wants a flexible 5-12-26 base formula for leaf and root growth.

About the Jack's 3-2-1 Program

The Jack's 3-2-1 program combines Part A FeED 5-12-26, Part B Calcium Nitrate 15-0-0, and Magnesium Sulfate (Epsom Salt), mixed in that specific order, to deliver a complete hydroponic nutrient solution.

Frequently Asked Questions

Where does this product fit in the Jack's 3-2-1 system?

This is Part A, the first component mixed in JR Peters' 3-2-1 hydroponic feeding system, used alongside Part B Calcium Nitrate and Magnesium Sulfate (Epsom Salt). JR Peters' own mixing guidance is to always mix Part A first, then Epsom Salts, then Part B last, to avoid precipitation in the reservoir.

How and when should this Part A formula be applied?

It promotes the growth of leaves and strong roots, blended with purely soluble and available nutrients that give growers maximum flexibility in how they build out a feeding program. Mix it into the reservoir first in the 3-2-1 sequence, according to label directions for the crop and growth stage.

Can this be used on its own, or does it need the other 3-2-1 components?

It's designed as one part of a three-part system, so pairing it with Part B Calcium Nitrate and Magnesium Sulfate delivers the complete, balanced 3-2-1 nutrient profile. Using Part A alone would leave out the calcium and magnesium the other two components provide.

What growing environments is this formula suited for?

This formula's flexibility across different growing environments and crop types is a stated feature, and it's marketed specifically for greenhouse and controlled-environment production. That positioning fits the rest of the Jack's Nutrients CEA lineup.