Jack's Classic Nutrients 15-0-0 Part B Calcium Nitrate Water-Soluble Fertilizer for Calcium Uptake and Strong Leaf Growth in Continuous Liquid Feed Programs, 25lbs

Can’t go wrong with Jack’s 321 line of products as long as it’s mixed properly. Always thumbs up!

I've used this for years and its never disappointed.

I started using the Jacks 321 formula in hydro and now use it in all my grows.

Much cheaper and better than it’s competitors

We appreciate Jack's hydroponic nutrients being available on Amazon. It saves us shipping costs with Prime. The nutrients, both A and B, are easy to use and very effective.

Then only reason for the 4 vs a 5 is my desire to have organic nutrients for my hydroponics. I cannot seem to find any that work as well.

For the money you get a good supply of fertilizer that is easy to mix and is the best I have found. If you want healthy plants you will be more then happy using this.

Don't buy any other brands of cal nitrate...this one is the best quality and it truly does make a difference..dissolves better too..