Ferrous Sulfate Heptahydrate - FeSO4*7H2O - 20% Iron - Very Soluble - 1 Pound

Easily dissolves in cold or warm water. Packaging is strong and durable. Did not precipitate out of solution at 5gram per liter. Very pleased.

I used ferrous sulfate on my plants when they were on the verge of dying, and the results were amazing! After applying it, the plants came back to life with vibrant, healthy leaves, and flowers in about two weeks. It truly revived them and is now a key part of my plant care routine. However, one thing to be cautious about is that it can leave stains on the floor or nearby surfaces, so it's important to apply it carefully or place something underneath to catch any drips.

After years of drought my Magnolia was suffering from lack of acidic rain and iron. I augered holes 18”-24” apart around the drip line and put a couple-three tablespoons in each hole and within 10 days the tree was coming back to vigor.

What it is & key properties • Chemical formula: FeSO₄·7H₂O, molecular weight ≈ 278.01 g/mol.  • Appearance: pale bluish-green crystals or granules.  • Solubility: fairly soluble in water (e.g., ~25.6 g per 100 mL at 20 °C) and insoluble in alcohol.  • Instability/oxidation: It’s air- and moisture-sensitive; the ferrous (Fe²⁺) form easily oxidises to ferric (Fe³⁺).  • Typical uses: Correcting iron deficiencies in soil/plants, water treatment (as flocculant or iron source), feed additive, precursor in chemical processes.  ⸻ 👍 Strengths / what it does well • Good iron source: Because Fe²⁺ is more bioavailable (in many contexts) than Fe³⁺, this salt is useful in agriculture and animal feed. • Relatively inexpensive and widely available: Many suppliers offer it in industrial/commodity quantities with decent purity. • Versatile in industrial chemistry: Useful in dyeing, pigment manufacture, reducing agent applications, etc.  • Water-soluble: Makes it easier to apply in aqueous systems (soil amendments, water treatment) compared with insoluble iron forms. ⸻ 👎 Weaknesses / limitations & caution • Stability issues: As noted, ferrous sulfate heptahydrate oxidises readily in moist air. Users report that even “fresh” greenish crystals turn brown/yellow over time (due to conversion to ferric compounds). “Fe(II) compounds slowly oxidize to Fe(III) when in contact with air … It should be blue/green. That has been oxidized.”  This means the “fresh” ferrous state may degrade unless handled and stored carefully. • Acidic and reactive: Its aqueous solutions tend to be acidic (pH ~3-4) which can affect compatibility with other materials.  • Limited use in some contexts: In food/feed applications, there are regulatory limits and specifications. For example, the Food and Agriculture Organization (FAO) monograph indicates specifications for purity etc when used as additive.  • Requires correct storage & handling: Because it’s hygroscopic and air-sensitive, handling and storage matter if you want consistent performance. Poor storage leads to degraded material (less Fe²⁺) and reduced efficacy. • Toxicity & safety: While generally of low hazard when handled properly, ingestion in large quantities, skin/eye contact etc pose risk.  ⸻ 🎯 Use-case suitability & recommendations If you’re considering using ferrous sulfate heptahydrate, here are how I’d rate its suitability, and what to watch for: • Great fit if: You need an affordable iron source (for plants, water treatment, feed), you’ll use it relatively soon after receipt, and you can store it properly (dry, sealed, away from air/moisture). • Less optimal if: You require long-term stability of the ferrous form (Fe²⁺) under ambient exposure, require high purity for analytic/chemical standards, or are in a field where oxidation or variable iron valence will cause problems. In those cases, a more stable iron salt (e.g., ferrous ammonium sulfate, chelated iron, or iron(III) compounds) might be better. • Storage tips: Store in a sealed container, keep dry, avoid prolonged exposure to air/moisture. Consider checking colour (blue-green → brown indicates oxidation). If you’re dissolving it for a solution, do it under low oxygen or acidified conditions if you need Fe²⁺. As one user noted: “You are better off using ferrous ammonium sulphate … ferrous sulphate is too easily oxidised.”  • Quality/purity concerns: If used for food/feed, check for heavy metals and regulatory compliance (e.g., arsenic, lead, cadmium levels). Suppliers list specifications (e.g., arsenic < 0.2 mg/kg etc).  ⸻ 🔍 My Verdict Overall I’d give ferrous sulfate heptahydrate something like 8/10 for its value, versatility and effectiveness in many standard applications (especially agricultural, industrial). But for precision, high-stability, or long-term storage uses, maybe around 5-6/10 due to its inherent tendency to oxidise and degrade.

No instruction of how to use. I just add small amount in one gallon of water and water the plants. Do not water above the leaves, it burns really bad. Water around the soil only. I used only once combined with fish emulsion. After a few weeks, new leaves look much healthier and happier. Probably won’t need it again for months or even a year.

My plants needed a boost and easy to use this did the trick great value for my money

I purchased this for use in Natural dyeing had to use 5x the weight of powder to get effect I am used to making this a very expensive waste of money. As noted in other reviews, this is a very impure product. MSDS sheet is misleading.

Works great for my eco printing projects.

I love this product! It's cheaper then liquid chelated iron for the most part , but the upside to it is that I don't need pgr any more at the proper doze you can keep your soil ph at the perfect levels . I recommend this Canadian product

This is an excellent product for moss control in your lawn. When I went to order more, Amazon.ca showed none available and no idea when that might change. Very disappointing Amazon.ca! It seems like product after product is out and the message on the website is, we really don't care about you as a customer.

Yet to see the result on flowers. Blackberry seems bearing fruits now.

Kills moss on my shady lawn! I sprayed 1/2 lb in 4 gallons of water over 1000 sqft, concentrating on the moss, and it all turned dark and dies within several days. I picked up the dead stuff and spread about 5 lb of lime after a few days.

I didn't use it personally but I brought this 5 months ago to my friend..he was very happy of it.