Jack's Nutrients 5-12-26 Hydroponic Professional Fertilizer Part A, 25lb | Part 1 of a 2-Step System, Targeted Micronutrient Package, Boosts Leaf Growth and Promotes Strong Roots

Best nutrients around, and the value is unbeatable. Will outlast dozens of bottles of premixed nutrients at a fraction of the price, with better quality and effectiveness. Don't waste your money on other brands or premixed nutes. These are the real deal when used with Part B.

I use this for my hydroponic grows, and this is like giving your plants steroids!!! It’s an old school fertilizer, but it has got to be the most effective fertilizer on the market!!! If you follow the instructions, your plants will grow so fast, and produce like nothing you have ever used before!!! There is nothing better simply put!!!!

I love this product and I dont have to keep buying it. The quantity is perfect

Jack's is the way.

I’ve used the Jacks 321 formula for years. Simple and reliable. Makes my autoflower plants look like photos. They grow great!

Had holes nutrient spilling out and box was beat up by Mike Tyson

This is my go-to Part A fertilizer, even for hydroponics. Dry fertilizers are always a better value than the liquid in a bottle counterpart, and give you more control over your mix. Make sure to get the Part B and C fertilizers to maximize the potential of the fertilizer, and to find out what amount you need for your specific usage. The price tends to fluctuate a lot, and ends up being over $100 in the Summer, so it may be worth stocking up in the Winter when people are using fertilizers less. Even if the price is around $100 however, you're still going to be saving so much money compared to the alternatives.

Jacks is my reccomendation. Stuff is cheap and works like a charm. My plant health is always perfect. I don't use bloom boosters and I'm bring home bigger crops than I was with more expensive line ups. Jacks 321 is where it's at.