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Phoenix Farms STS Spray 16 oz


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Phoenix Farms Silver Thiosulfate Solution (STS) spray is specifically formulated to create feminized seeds for home and commercial growers. The feminization rate is approximately 95% for all types of plants.* 


This product is premixed and ready to use; do not dilute

Wear gloves, safety glasses, and a face mask. Turn off all fans and lights. 

To keep STS out of your soil, try to use newspaper or a plastic barrier until dripping stops from application.

Apply STS Spray liberally at night to a female plant starting four days after flipping the lights; repeat every three to five days for two to three weeks or until male sacs appear and are well developed. 

Depending on your needs, spray a whole plant or just one branch. 

Continue growing until pollen sacs open and produce pollen. Collect the pollen by gently shaking the male flowers over a container. The pollen will fall into the container and can then be stored. Pollen should be dried first and stored in a cool, dark place. To dry pollen, spread it out on a piece of paper or cloth in a well-ventilated area. The pollen should be dry within a few days. 

Apply pollen with a Q-tip or small paint brush to female “buds” or flower sites. We recommend starting your proposed male plants two weeks before planting your female candidates to ensure your females aren’t blooming before your males. 

Let developing seeds fully mature or ripen by extending your flowering time by two weeks past the regular harvesting date. 


Silver Thiosulfate Solution is light temperature sensitive. Store in your refrigerator or a cool, dark place. 


90 days from the purchase date. 


Phoenix Farms a veteran-owned and operated small business. 

*Please note that there is no chemical formula that will feminize all phenotypes of plants 100% of the time. You should experiment and learn what works for your specific plant strain. 



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