Humboldts Secret Calcium, Magnesium and Iron Supplement – Hydroponic Supplies – Liquid Nutrient Fertilizer – Supports Vegetative and Flowering Stage – 1 Quart

I never had any idea how deprived my plants were untill I gave them some of this! There was a burst of growth I've never seen before! Calmag with iron allowed them to grow as fast as they wanted to,the leaves got bigger than I ever imagined they could, they smell very pungent too! This stuff is awesome! I'll never grow without it again!!!

Size was great lasts long time but works quickly. Easy to usedursble seal was great promoted growth no smell

Great product works well

Works great 👍

Had some maple trees that are prone to iron deficiency. Got this so I could solubilize it and apply to the roots. Couldn't see exactly how much, wrote the company an e-mail and heard back the next day with specific amounts and instructions. Amazing! Pretty rare to get that kind of corporate response. Best of all, my trees snapped right back (about 3 weeks). Apply once a month and they just keep getting more and more green. Will definitely buy again to start applying next spring. Saved my trees lives, literally.

I only buy this stuff, we get a good amount for a great price, I have never been let down by and neither have my plants

2023 has been a brutal year for my garden. The rains of winter gave rise to swarms of insatiable insects, some of which I had never seen before. Then, we had record temps that turned many of my plants into crispy critters no matter how much I watered them.The few tomato plants that didn't wilt into oblivion then developed BLOSSOM END ROT! Knowing that BER is often caused by a lack of calcium, I ordered this product. Unlike traditional garden Epsom salt, this Humboldt formulation also includes magnesium, which helps the plant absorb more calcium, along with iron. I gave it to my tomatoes and within a week, blossom end rot stop being a thing. I also used it on my "other" types of plants that are legal in many places. They LOVED it! I am now trying on my trees and hoping Humboldt's Secret will help them endure what I hope are the last few days of scorching temps.

I bought a quart of this for my tomato plants, it mixes 1-1/4 teaspoon to a gallon of water