Sodium Thiosulfate Panreac – Create Your Own Feminized Seeds (STS)

Panreac Sodium Thiosulfate is the key that unlocks the door to advanced cannabis breeding, allowing you to create Silver Thiosulfate (STS) to produce 100% feminized pollen from your favorite female plants.

Why you need this to master your genetics

Imagine finding that perfect phenotype—incredible terpene profile, rock-hard buds, and vigorous growth—only to realize you didn't take a cutting, or worse, your mother plant gets sick. You rely constantly on buying new seeds, hoping to get lucky again, but deep down you know that specific magic is lost forever. It’s the grower’s worst nightmare: instability and dependence.

It is incredibly frustrating to spend months perfecting a grow room and dialing in your cannabis fertilizers, only to have no way to preserve the exact genetics that performed best. You feel like you're always starting from scratch, wasting time and money hunting for keepers that you can't keep permanently. Without the ability to make your own seeds, you are just a consumer, not a creator.

Sodium Thiosulfate changes the game completely. By combining this chemical with Silver Nitrate, you create STS, a compound that inhibits ethylene in female plants. The result? Your female plant starts producing male flowers loaded with female pollen (XX). When you use this pollen to pollinate another female, the resulting seeds are feminized. You secure your genetics, save money, and gain total control over your garden's future.

What exactly is Panreac Sodium Thiosulfate?

This product is a 500g container of laboratory-grade Sodium Thiosulfate (Na2S2O3), known in the breeding community as "Part B" of the STS formula. It is not a fertilizer, but a chemical reagent essential for sex reversal.

• High Purity: Panreac guarantees lab-grade quality, ensuring your chemical reactions are precise and safe for the plant's hormonal system.
• Massive Yield: 500g is enough to make liters and liters of stock solution. Since you only use grams at a time, this bottle will likely last you for years of breeding projects.
• Versatility: It is the standard industry choice for making STS, which is far more stable and effective than Colloidal Silver for reversing difficult strains.

How your routine changes from now on

Once you start using Sodium Thiosulfate, you stop worrying about running out of your favorite strains. Your routine shifts from passive maintenance to active creation. You will set aside a small space for "reversed" plants, spraying them on a schedule to harvest pollen.

Instead of just harvesting buds, you'll be harvesting the future of your garden. You will have jars of your own seeds labeled with your own cross names. The satisfaction of popping a seed that you created and seeing it thrive is unmatched in the cultivation world. You become self-sufficient.

Advantages and benefits you’ll notice from day one

• Genetic Preservation: You can create "Selfed" (S1) seeds of your favorite clone, preserving it in seed form indefinitely.
• Cost Efficiency: One bottle costs less than a single pack of high-end seeds but allows you to produce thousands of them.
• Professional Stability: STS produced with Sodium Thiosulfate creates more viable pollen and more consistent sex reversal than other home remedies.
• Creative Freedom: Mix your favorite Sativa with that heavy Indica you love. You are the breeder now.
• Long Shelf Life: The powder (and the unmixed stock solution) remains stable for a long time if stored correctly.

Tips to combine it with other products

Sodium Thiosulfate is useless on its own for breeding; it is part of a binary system. To create the active STS spray, you must be prepared with the right tools and complementary chemicals.

• Silver Nitrate: This is "Part A". You must mix Sodium Thiosulfate with Silver Nitrate to create the reaction. Without it, this product won't reverse sex.
• Distilled Water: Never use tap water. The chlorine and minerals will ruin the chemical reaction.
• Cloning Supplies: You will want to practice sex reversal on rooted cuttings rather than large plants to save space and resources. Check our cloning section for gels and scalpels.
• Protection: Always use gloves and a mask when mixing and spraying chemicals.

Frequently Asked Questions

How do I mix it to make STS?

A standard recipe involves making two stock solutions. Stock B is usually made by mixing roughly 1.56g of Sodium Thiosulfate into 40ml of distilled water (ratios vary by recipe, always verify your specific STS formula). You then mix it with Stock A (Silver Nitrate) and dilute with water before spraying.

Can I smoke the plant I sprayed?

Absolutely NOT. Plants treated with STS contain silver thiosulfate, which is toxic if ingested or inhaled. Any plant sprayed with this solution must be destroyed after the pollen is harvested. Never consume flowers from a reversed plant.

When do I start spraying?

Generally, you start spraying your female plant 5 days before switching the light cycle to 12/12, and then repeat every 5 days for a few weeks until male sacs form.

Is this better than Colloidal Silver?

Yes. STS is more stable, requires fewer applications, and is generally more effective at forcing stubborn female plants to produce male flowers compared to colloidal silver.

Personal Experience of Pevgrow’s CEO (Alan)

I'll be honest, the first time I decided to make my own seeds, I was intimidated by the chemistry. I started with colloidal silver because it seemed "easier," but the results were inconsistent—barely any pollen and a lot of wasted time. When I switched to the STS method using Sodium Thiosulfate and Silver Nitrate, it was night and day.

I remember reversing a classic Amnesia cut that I was terrified of losing. The process was surprisingly simple once I had the stock solutions mixed. The amount of pollen I got was insane, and the resulting S1 seeds were virtually identical to the mother. My advice? Don't be scared of the "lab" aspect. Buy a precision scale, get this Sodium Thiosulfate, and respect the safety protocols. It’s the single biggest level-up you can make as a grower.