Why did STS fail? 

most common would be.

"Using tap water instead of distilled" (the minerals ruin the silver), "Mixing in the wrong order" (pouring B into A), or "Applying under heavy lights" (UV light kills STS).

Pro Tip: Never use tap water for STS. The chlorine and minerals will cause the silver to "bond" and fail. Distilled water only ensures the chemical stays active for the plant.

We perfected this reversal timing specifically for the Ontario photoperiod and Canadian autoflower cycles.

Treated plants are never for consumption. Dispose of treated foliage responsibly.

Bred in the heart of Ontario, we use this STS method to ensure our Purple Kush Auto can handle the unique humidity and light cycles of the Great Lakes region.

How long does mixed STS solution last?

​Once you combine your Part A (Silver Nitrate) and Part B (Sodium Thiosulfate) into a Stock Solution, it is viable for 30 days if stored in an airtight, light-proof amber glass bottle in a cool refrigerator. The individual, unmixed powders have a near-indefinite shelf life if kept dry. If you see black or grey "precipitate" (bits) in your liquid, the silver has fallen out of solution and it is time to mix a fresh batch.

​Can I save and store feminized pollen?

​Yes. To store pollen long-term, it must be kept bone-dry. We recommend mixing your collected pollen with toasted flour (ratio of 4:1 flour to pollen) to act as a desiccant. Place it in a sealed, airtight vial with a silica gel packet and store it in the freezer. When frozen correctly, feminized pollen can remain viable for up to one year.

​What are the signs that the STS reversal is working?

​Typically, between 14 and 21 days after your first spray, you will notice the plant's growth "stalling" or lagging—this is a sign the chemical is working. Soon after, you will see the formation of male pollen sacs instead of white pistils. For stubborn strains, you may need a fourth application to ensure full conversion.

​Can I use tap water for my STS mix?

​Never. The minerals, chlorine, and fluoride in tap water will immediately react with the Silver Nitrate, causing it to "crash out" and turn cloudy. This neutralizes the solution, making it useless for reversal. Always use 100% Distilled Water for both the stock solutions and the final spray dilution.

​Can I smoke the plant after I’m done?

​No. Any part of a plant treated with STS contains heavy metal residues. This material is strictly for breeding purposes only. At Twisted Genetics, we prioritize safety: treated plants should be harvested for seeds/pollen and then safely discarded. Do not consume, vape, or make edibles with treated material.

​Need Expert Help or Lab Supplies?

​At Twisted Genetics, we are more than just a seed bank—we are active breeders. If you are a Canadian grower looking to start your own reversal project and need high-purity Silver Nitrate or Sodium Thiosulfate Pentahydrate, we can help you source the professional-grade chemicals you need.

​If you have questions about the timing for a specific strain or need troubleshooting on a reversal that isn't dropping pollen, feel free to reach out to the Twisted Genetics team. We are here to support the Ontario growing community of all growers with real, breeder-level expertise.

​Contact Us Today for Lab Supplies or Breeding Support

Why did STS fail? 

most common would be.

"Using tap water instead of distilled" (the minerals ruin the silver), "Mixing in the wrong order" (pouring B into A), or "Applying under heavy lights" (UV light kills STS).

Pro Tip: Never use tap water for STS. The chlorine and minerals will cause the silver to "bond" and fail. Distilled water only ensures the chemical stays active for the plant.

We perfected this reversal timing specifically for the Ontario photoperiod and Canadian autoflower cycles.

Treated plants are never for consumption. Dispose of treated foliage responsibly.

Handling the chemicals for STS reversal requires professional respect. At Twisted Genetics, we prioritize garden safety and human health. You must use the following Personal Protective Equipment (PPE) whenever mixing or spraying:

​1. Chemical-Resistant Nitrile Gloves

​Why: Silver Nitrate is a caustic salt. If it touches your skin, it reacts with your proteins to create Silver Chloride, leaving stubborn black or brown stains that can last for weeks. High concentrations can cause actual chemical burns or tissue damage.

​2. Protective Eyewear (Safety Goggles)

​Why: This is the most critical rule. Accidental splashes of Silver Nitrate in the eyes can cause severe irritation, corneal damage, or in extreme cases, permanent vision impairment. Never mix these chemicals without sealed eye protection.

​3. Dust Mask or Respirator (N95 Recommended)

​Why: When handling the dry Sodium Thiosulfate or Silver Nitrate powders, you must avoid inhaling the dust. Inhalation can irritate the respiratory tract, causing coughing or shortness of breath. Long-term exposure to silver dust can lead to Argyria, a permanent blue-gray discoloration of the skin and internal tissues.

​4. Long Sleeves and Proper Footwear

​Why: To prevent "permeation" (where chemicals soak into your clothes and sit against your skin), always wear long sleeves and closed-toe shoes. If you spill the solution on your clothes, change them immediately.

​Environmental Responsibility & Disposal

​Never Smoke Treated Plants: This is non-negotiable. Plants treated with STS contain heavy metal residues (silver). Smoking or consuming these plants can lead to heavy metal poisoning.

​Safe Disposal: Silver Thiosulfate is highly toxic to aquatic life and can damage soil microbes if dumped down the drain or into the garden. Once your seeds are harvested, dispose of the treated plant material in the trash, not your compost pile.

​Storage: Keep your Stock Solutions in labeled, child-proof glass containers in a cool, dark place (like a dedicated seed fridge) away from food and drink.

Genetics Bred for the North: The Ontario Advantage

The Twisted Genetics STS protocol wasn't just copied from a textbook—it was refined right here in Ontario. We developed our specific timing and 1:9 dilution ratios to work with hardy, short-season genetics like our Purple Kush Auto.

​Growing in the Great Lakes region means dealing with unique humidity spikes and unpredictable light cycles. By using this lab-grade reversal process, we ensure our seeds carry the stability and vigor required to thrive in the Ontario climate, whether you are growing in a high-tech indoor tent or a Southern Ontario backyard.

The Secret to 100% Female Crops

​Welcome to the lab at Twisted Genetics! If you have ever wondered How to Make Feminized Seeds, you’ve come to the right place. The foundation of any elite grow starts with a simple truth: feminized seeds produce exclusively female plants. This is the "Holy Grail" for growers because it eliminates the risk of a random male pollinating your entire tent and ruining your hard-earned buds.

​To get these results, we use a professional technique called feminization. While it might sound like mad science, it is actually a natural biological hack. In the wild, female cannabis has a survival mechanism that allows it to produce male pollen if it thinks it’s going to die without being pollinated. In the breeding world, we tap into this through a process called "feminization" by using an ethylene blocker like STS or colloidal silver.

​How it Works: The Sex Reversal Secret

​So, how exactly are feminized seeds created? It all comes down to hormones. By spraying a healthy female cannabis plant with a silver solution, we temporarily block ethylene—the hormone that tells the plant to grow female flowers (pistils). When the ethylene is blocked, the plant gets "confused" and begins to grow male pollen sacs instead.

​However, because the plant is genetically female (XX chromosomes), the pollen inside those sacs contains zero male (Y) chromosomes. This is the heart of feminized seed production. When this special "female pollen" hits the pistils of another female, the resulting feminized seeds are created with a 99.9% guarantee of being female.

​Why Precision Matters

​This technique called feminization requires patience and a clean environment. Whether you are working with our Elite Purple line or an emergency Purple Kush run, understanding the process called "feminization" allows you to preserve your best genetics forever. When you learn How to Make Feminized Seeds, you aren't just growing; you are creating a legacy. Remember, because feminized seeds produce exclusively female plants, every single seed you create is a high-value asset for your garden.

The Great Silver Showdown: CS vs. STS

​When it comes to seed feminization, every breeder eventually asks: "Which silver is king?" To successfully pull off a sex reversal, you have to choose a tool that fits your grow style. Both methods work by tricking female plants into thinking they are male, but the way they get there is totally different. Let’s break down the two heavyweights of the breeding world so you can start producing your own cannabis seeds.

​Colloidal Silver (The "Old School" Reliable)

​Many home growers use colloidal silver (CS) because it is easy to find and safe to handle. If you are using a 40ppm solution, you are in the "Sweet Spot" for potency.

​The Process: You have to be dedicated. CS requires daily spraying of the nodes and future flowering sites from the moment you switch to a 12/12 light cycle until the pollen sacs are fully formed.

​The Downside: It’s a lot of work! If you miss just a couple of days, the plant's natural hormones can take back over, and you'll end up with regular buds instead of the sex reversal you were hoping for. Also, CS doesn't travel through the plant; it only works exactly where you spray it.

​STS Spray (The Professional Standard)

​Silver Thiosulfate (STS) is what the big seed banks use for feminizing seeds at scale. Unlike CS, STS is "systemic," meaning the plant absorbs it and moves it through its system.

​The Process: Instead of spraying every single day, you usually only spray once every 5 to 7 days. You focus on the nodes where the branches meet the stem, and the chemistry does the rest.

​The Upside: It is much more powerful. For growers use, STS is more efficient because it completely shuts down ethylene production. This results in a "cleaner" reversal with more viable pollen. If you want a massive harvest of cannabis seeds, STS is often the way to go.

​Protecting the Genetic Blueprint

​No matter which method you choose, the goal is the same: protecting the genetic integrity of your strain. When we reverse a female, we are essentially making a "clone" in seed form. This seed feminization allows you to keep your favorite mother plant's traits locked in forever.

​Remember, once the sex reversal begins, that plant is no longer for smoking—it is a dedicated pollen donor. You won't be harvesting smokable buds from this plant; instead, you’ll be preparing for a harvest of high-grade seeds.

The Roadmap to Feminized Success

​So, you’ve picked your favorite mother plant and you're ready to lock in those genetics forever. Whether you are using cloning to make a backup of your prize Purple Kush or starting from a fresh seedling, this step-by-step guide will walk you through the professional techniques used by the pros to ensure a successful sex reversal.

​Step 1: Selecting Your Star Performer

​Before you even touch a spray bottle, you need a healthy candidate. Feminizing seeds starts with a strong, pest-free female. Most breeders prefer cloning their target plant first. Why? Because you never want to reverse your "only" mother plant. By using a clone, you can flip the sex of the copy while keeping the original mother plant safe for future runs.

​Step 2: The Pre-Flip Prep

​Treat your female plants like royalty in the week leading up to the flip. Ensure they have a balanced diet of nutrients, specifically focusing on healthy root development. A plant under stress won't produce much pollen, so make sure your Nitrogen and Phosphorus levels are dialed in.

​Step 3: The "Flip" and the First Spray

​When you switch your lights to a 12/12 cycle, the clock starts.

​If using Colloidal Silver: Start spraying the nodes daily.

​If using STS: Apply your first thorough spray on Day 1.

You are targeting the areas where the female flowers would normally grow. You are essentially telling the plant's genetics to change course!

​Step 4: Monitoring the Transformation

​Between Day 14 and Day 21, the magic happens. You’ll notice the growth at the nodes looks different—less like white hairs and more like small, clustered balls. This is the successful result of your reversal techniques. Keep your nutrients steady (switch to a "Bloom" formula) to give the plant the energy it needs to build those pollen sacs.

​Step 5: Controlled Pollination

​Once the sacs ripen and begin to open, it's time for pollination. You can either let the "pollen donor" sit in a tent with your other female plants or collect the pollen manually. Manual pollination is often better for beginners because it allows you to paint the pollen exactly where you want it, ensuring you get a targeted harvest of seeds without seeding every plant in the room.

​Step 6: The Seed Ripening Phase

​After pollination, the plant will stop focusing on "getting high" and start focusing on "motherhood." It takes about 6 weeks for the seeds to fully mature. You’ll know they are ready when they look dark, hard, and have those beautiful "tiger stripes."

The Master Chemist’s Kitchen: Mixing Your Reversal Spray

​Ready to stop buying seeds and start making them? To make feminized cannabis seeds that actually germinate and grow into monsters, you need a precise recipe. Think of this like baking—if your measurements are off, the "cake" (or in this case, the sex reversal) won't rise.

​While many growers use store-bought solutions, the pros mix their own Silver Thiosulfate (STS) for maximum stability and potency. Here is the official Twisted Genetics breakdown for a professional-grade reversal.

​The Shopping List (The Essentials)

​Before you start, gather these specific supplies. Do not substitute tap water—minerals will ruin the reaction!

​Silver Nitrate: The "Active" ingredient.

​Sodium Thiosulfate: The "Stabilizer."

​Distilled Water: The only liquid you should use.

​Brown Glass Bottles: To protect your solution from light.

​Digital Scale: Needs to measure to 0.1g accuracy.

​Part A: The Silver Nitrate Solution

​Measure out 0.5 grams of Silver Nitrate.

​Pour it into 500ml of distilled water.

​Stir until the crystals are completely dissolved.

​Label this "Part A" and keep it in a dark bottle.

​Part B: The Sodium Thiosulfate Solution

​Measure out 2.5 grams of Sodium Thiosulfate (Anhydrous) or 3.9 grams of Sodium Thiosulfate (Pentahydrate).

​Pour it into 500ml of distilled water.

​Stir until clear.

​Label this "Part B."

​The Golden Rule: Mixing the "Working Solution"

​This is where the magic happens. To create your actual spray to make feminized cannabis seeds, you must follow this order:

​Always pour Part A into Part B while stirring rapidly. * Never do it the other way around, or the silver will "precipitate" and turn into useless black gunk.

​Dilution: Take your mixed solution and dilute it at a ratio of 1:9 with more distilled water (e.g., 100ml of mix + 900ml of water).

​Safety First, Genetics Second!

​Working with these chemicals is safe as long as you are smart.

​Wear Gloves: Silver nitrate will stain your skin brown/black for days if you touch it.

​Wear a Mask: You don't want to breathe in the mist when you're spraying your female plants.

​Protect the Eyes: Always wear safety glasses.

​The "No Smoke" Policy: Once a plant has been treated with this recipe, it is toxic. Never smoke, eat, or process a plant that has been sprayed with silver. Its only job now is to provide you with a massive harvest of cannabis seeds.

​Whether you are rocking the daily grind of Colloidal Silver (40ppm) or the surgical precision of STS, timing is everything. If you want a massive yield of high-quality cannabis seeds, you have to know what to look for at every stage. A successful sex reversal isn't just about spraying; it’s about reading the plant’s signals and reacting at exactly the right moment.

​The Colloidal Silver (40ppm) Timeline and Expectations

​Using Colloidal Silver is a marathon, not a sprint. Because this solution is not systemic, you are the boss of every single node. You have to be consistent to ensure the ethylene stays blocked.

​Days 1–14 (The Transition Phase): During these first two weeks, you are looking for the "Slight Twist." You’ll notice new growth starts to look a bit shiny or slightly "clawed" at the tips. This is a great sign—it means the silver is successfully starting to block the ethylene production in those specific areas. Keep spraying daily!

​Days 15–21 (The Cluster Phase): This is exactly what you are seeing right now at Twisted Genetics! Tiny green clusters start to form where the buds would usually be. You should see absolutely no white hairs in sight—just pure, smooth clusters that look like miniature green grapes.

​Days 22–35 (The Maturation Phase): This is the "Yellowing" stage. The sacs swell up and turn from a deep, healthy green to a pale, buttery yellow. This is your signal to stop spraying immediately. If you continue to spray now, you risk damaging the delicate "dust" inside or making the sacs too leathery to open.

​Day 40 and Beyond (The Harvest Phase): Finally, you reach the "Dust Drop." The vertical seams on the sacs will crack open, revealing the yellow stamens. It is officially time to harvest that genetic gold.

​The STS (Silver Thiosulfate) Timeline and Expectations

​On the other hand, STS is the "Set it and Forget it" version of breeding. It is much more aggressive and works from the inside out.

​Day 1 (The Initial Flip): You give the plant its first heavy spray. The plant immediately absorbs the silver thiosulfate, moving it through its entire vascular system to prepare for the sex reversal.

​Day 7 (The Hormone Shift): You apply your second spray. By this point, the plant’s internal chemistry has completely flipped. You may see some slight yellowing of the leaves, which is a normal sign of the silver taking hold.

​Day 14 (The Sac Explosion): You will see rapid sac formation that often appears much more "crowded" than a Colloidal Silver reversal. Because the chemistry is so much stronger, the plant produces male flowers with much less effort.

​Day 30 (The Early Drop): STS usually finishes a full week faster than CS. You can often expect an early pollen drop by Day 30, allowing you to get your pollination started even sooner.

​Detailed Growth Signs to Watch For

​As you progress through the sex reversal, pay close attention to the nodes. During the early stages, the most important sign is the absence of pistils (white hairs). If you see hairs, you need to increase your spray coverage. As the clusters grow "chunky," make sure your airflow is high; tight clusters can trap moisture, which leads to mold.

​When the sacs look "puffy" and you can see a distinct vertical seam, you are in the home stretch. This is the moment to lower your humidity to 35% or 40% immediately. High humidity is the enemy of high-quality cannabis seeds because it makes the pollen clump together like mud. Once you see that fine yellow dust appearing on the leaves below the sacs, you know the genetics are ready to be captured.

​Maximizing Your Final Seed Yield

​To get the most high-quality cannabis seeds, don't just pollinate once. Use the Paintbrush Method: Collect your pollen on a glass plate and "paint" it onto the white pistils of your female receiver plant three days in a row.

​Once pollination is successful, you must wait for the "Tiger Stripe" sign. The seeds need 5 to 6 weeks to finish. If you harvest too early, the seeds will be green and won't sprout. Wait until the calyxes look dry, crispy, and brown—that’s where the "armor-plated," tiger-striped cannabis seeds are hiding, ready for the season!

Mastering the Sex Reversal: Pro-Tips and Troubleshooting

​Even with elite genetics and a perfect schedule, nature can be stubborn. If you are struggling to make feminized cannabis seeds, don't panic—every master breeder has faced a "dry" reversal. Most issues come down to small environmental tweaks. Here is how the pros handle the most common roadblocks in the process called "feminization."

​Pro-Tip 1: The "Hollow Sac" Syndrome

​Sometimes, you’ll see beautiful, yellow pollen sacs that look perfect, but when they open, they are empty. This is often caused by heat stress. If your grow room is over 27°C (80°F), the pollen can "cook" inside the sac.

​The Fix: Keep your "Donor" plant in a slightly cooler environment—around 22-24°C (72-75°F). This keeps the pollen viable and "powdery" rather than clumping.

​Pro-Tip 2: The "Surgical" Harvest

​If your sacs are stubborn and won't drop dust on their own, use the "Surgical Technique." Take a sterilized needle or a pair of fine-tip tweezers and manually "zip" open the seam of a yellowing sac over a glass plate.

​Breeder's Secret: If the pollen is slightly clumped, put it in a small jar with a single dry grain of rice. The rice acts as a natural desiccant, pulling moisture out of the pollen without over-drying it.

​What if I see both sacs and white hairs?

​This is known as a "partial reversal" or "hermaphroditic response." It happens when the technique called feminization wasn't aggressive enough, or your colloidal silver 40ppm wasn't applied thoroughly to the nodes.

​The Fix: If you see white hairs (pistils) emerging, increase your spray frequency immediately. For your next run, this is a sign you should switch to STS spray, which is systemic and much more reliable for stubborn female plants.

​Dealing with "Leathery" Sacs

​If you sprayed too late into the cycle, the sacs might become "leathery" and tough, making it impossible for them to pop.

​Pro-Tip: If this happens, give the plant a light misting with distilled water (no silver!) once. This shot of moisture can sometimes soften the outer shell of the sac just enough to let it crack open as it dries back out under the fans.

​Ensuring 100% Seed Germination

​If you successfully pollinate but your seeds look pale, white, or feel soft, they are "immature." High-quality cannabis seeds need a full 6 to 8 weeks to develop their protective armor.

​The Final Trick: Never harvest based on the calendar. Harvest based on the "Calyx Crumble." Rub a seed pod between your fingers; if the pod turns to dust and a dark, tiger-striped seed falls out effortlessly, your feminized seed production is a total success.