STS Silver Thiosulfate Breeding

in Breeding Sun Nov 24, 2013 9:30 pm
by ozzydiodude • The Weird One | 2.084 Posts | 10103 Points

Originally posted by Massproducer at MP

STS Silver Thiosulfate Breeding
I just found this while doing a bit of research and decided I would share it with all of our wonderful members.

STS-based reversals and feminized breeding

Terminology for STS breeding:
STS: Silver thiosulfate, a salt compound used in photography. In plants, silver interferes with, or locks out, copper, which is a necessary micronutrient. Making copper unavilable inteferes with ethylene signaling, and reduces expression of traits that are dependent on high levels of ethylene, such as female sex expression and fruit ripening.
Copper: a micronutrient that is necessary to assist certain enzymes in their function. Copper can become toxic at low levels, but a few parts per billion is adequate for plants to express their genetic potential. Because copper is needed at such low levels, it does not take much silver to overwhelm the available copper load and exert its effect.
Ethylene: One of the 5 plant hormones. The levels and ratios of these 5 hormones has a huge impact on the shape, strucutre, aroma, flavor, flowering time, and disease resistance of the plant. Hormones are the chemical messengers that allow DNA to 'talk' to plant tissues and determine the phenotype. Ethylene is primarily involved in flowering, sex determination, fruit ripening, and sensescence (rot). Ethylene is a simple organic molecule, C2 H4, which can also be represented as H2C=CH2.
In cannabis, female plants will produce male flowers if not enough ethylene is present, or if too much gibberellic acid is present. The intersex condition is due to a combination of genetic and environemental factors. Some plants will not turn male under the most extreme stress, and some plants, especially stretchy tropical sativas, will turn with no stress at all. It is my belief that the stress of severe inbreeding, compounded over several generations, is responsible for the majority of hermaphrodites in the drug cannabis gene pool (DCG) today.
Reversal: Treating a female plant with STS in order to collect viable female pollen.
Selfing: Applying female pollen to the female from which it was collected. Example : selecting a particular Willie Nelson cutting, reversing it, and putting the pollen back on another clone of the same plant. Applying that pollen to a different Willie cutting, or to another strain altogether, is not selfing.
F0: The parents selected to start a breeding program. Often referred to as P1 and P2, but this is incorrect.
F1: the first cross between two unrelated parents. The F stands for filial, and refers to the fact that all F1 progeny of the same cross are full brothers and sisters to one another.
S1: The first selfed generation. Selfing an S1 produces an S2, etc. Anecdotal evidence from Sam_Skunkman indicates that continued selfing to the S3 and S4 produces plants so weak that they must be handled very carefully, “like kittens” in his words.
R1's (aka Reversed F1's): When feminized pollen is used to pollinate a different female than the pollen donor. R1's will tend to act like a tradional male x female cross, only all female, while S1's appear to have some different properties that are not yet fully understood. Early reports indicatee that S1's are more consistent than R1's on average, but there are many exceptions, and more research is needed.
BC1: The first backcross generation, ie when an F1 or R1 progeny is crossed back to an F0 parent. Backcrossing can increase the influence of either parent, but continued backcrossing is too much inbreeding, according to both DJ Short and Rezdog, and should be used rarely if at all. One or two backcrosses followed by full-sib mating has beena successful strategy for many breeders, including the creator of Northern Lights.
These terms can be combined for shortand pedigrees. A second backross, followed by three generations of sib-mating, may be represented as a BC2-F3 generation.
Intersex: A condition in which a plant (or animal) displays functional sex organs of both genders. Easier to type than hermaphroditic. My belief is that almost all hermies are genetic females that have weaknesses in their ethylene signaling pathway, which makes them very susceptible to environmental stress.
Stress: Any environmental factor that causes a response by the plant. Stresses can be biotic or abiotic. Biotic stresses include insects, fungi, viruses, predators, and CAMP. Abiotic stresses include drought, poor soil conditions, extreme wind or humidity, or hurricanes or flooding. Both types of stresses can have large effects on phenotype, including induction of intersex phenos.
Hybrid Fertility: The degree to which any two unrelated plants can set seed. For example, crossing an Afghani to a Turk may produce 95% viable seed, whild crossing Durban to Mongolian Indica might only produce 40% viable seed. This is usually a measure of the genetic distance between the parents. The fertility of self-pollinations is unknown but could give the breeder alot of information about the breeding value of the plant in question. A plant that has a desirable phentoype, but is not very self-fertile, is likely very homozygous and will tend to produce consistent offspring.
Micropropagation: Taking very small clones and rooting them in test tubes containing a heat-sterilized nutrient mixture in a agar (gelatin) base. This allows for aseptic (almost sterile) conditioins and precise application of phytochemicals such as STS, auxin, or cytokinin.

Flower parts:


Petal: the 5 yellow petals surrounding the generative organs
Anther: the banana-shaped pod on a thin stalk that produces and drops pollen
Filament: the thin stalk that supports the anther.
Pollen grain: A tiny, round, hard shell that floats on the wind until it lands on a female stigma.
Sperm: A half-copy of the genetic information of the father. Each grain contains two sperm. One sperm fertilizes the egg and forms the embryon, while the other sperm fertilizes another cell and forms the endosperm, the fatty, protein-rich substance that surrounds the embryon and provides nutrients for the first ~2 weeks of growth. This process is called 'double fertilization' and is pretty cool if you want to read more about it.


Sepal: the small green leaves subtending (underneath) the petals. The sepals are the strucutres that have two white hairs protruding and are covered in resinous trichomes. They are a leafy jacket for the developing seed. I believe that the evolutionary purpose of THCis to confuse animals, such as mice and voles, that eat cannabis seeds after they fall to the ground. Differences in cannabinoid content probably are due to differences in the brains of the seed predators.

Stigma: The two white hairs that stick out of each flower. Each stigma is capable of accepting pollen and directing it to the ovary, which is located at the base of the seed. The stigma is capable of performing a chemical analysis of the pollen that lands on it, and can decide whether ornot to allow that pollen to germinate and fertilize the embryo.

Ovary: the structure that contains a half-copy of the maternal DNA, which fuses with a sperm to form an embryo that contains 50% DNA from each parent.


Achene: a technical term for the particular type of seed that Cannabis produces. Similar to a nut, but simpler in structure.

Aleurone: the hard, tiger-striped outer shell of a seed that protects the delicate embryo and endosperm.

Vernalization: Any environmental or chemical treatment that induces seeds to sprout. This can be heat, in the case of wild tomato or avocado seeds, or cold, as in the case of poppies and many members of the cabbage family. Some seeds require a bath in acid, as in tomato seeds, which tend to to sprout well when they are incubated in the hot, acidic bath known as the 'stomach' and then deposited in a matrix of rich organic matter, known as 'poop'.

you've got it

here is an aticle on the actual method. I got this from Rez dog, from Reservior seeds:

Silverthiosulfate Prep 101

Preparation of STS:

First, a stock solution is made. It consists of two parts (A and B) that are initially mixed separately, then blended together. Part A is ALWAYS mixed into part B while stirring rapidly. Use distilled water; tap water may cause precipitates to form.

Wear gloves while mixing and using these chemicals, and mix and use in a properly ventilated area. A mask will prevent the breathing of any dust, which is caustic. STS is colorless and odorless, and poses minimal health risks if used as described here. (See material safety data sheet links below). Note that silver nitrate and STS can cause brown stains upon drying, so spray over newspaper and avoid spilling.

Part A: .5 gram silver nitrate stirred into 500ml distilled water
Part B: 2.5 grams sodium thiosulfate (anhydrous) stirred into 500ml distilled water

The silver nitrate dissolves within 15 seconds. The sodium thiosulfate takes 30-45 seconds to dissolve.

The silver nitrate solution (A) is then mixed into the sodium thiosulfate solution (B) while stirring rapidly. The resulting blend is stock silver thiosulfate solution (STS).

This stock solution is then diluted at a ratio of 1:9 to make a working solution. For example, 100ml of stock STS is added to 900ml of distilled water. This is then sprayed on select female plants.

Both the stock STS and the working solution should be refrigerated after use, as well as the powdered chemicals, to avoid activity loss.

The adjusted formula is as follows:

Part A: .7 gram silver nitrate stirred into 40ml distilled water
Part B: 2.6 grams sodium thiosulfate (anhydrous) stirred into 160 ml distilled water

Next, slowly add the silver nitrate solution to the sodium thiosulfate solution while stirring. This combination is then added to 800 ml of distilled water to equal 1 liter. This is your final stock solution. It is diluted 1:9 with more distilled water to make your final working solution, which then gets sprayed on your target plant.

Either formula will work great, so don't sweat it too much. But do that second spraying at the end of week 2... seems to be the key for getting pollen from the more difficult strains.


The STS working solution is sprayed on select female plants until runoff. Do the spraying over newspaper in a separate area from the flower room. You probably won't smell anything, but ventilate anyway. You now have what I call a "F>M plant"; a female plant that will produce male flowers.

After the F>M plant dries move it into 12/12 immediately. This is usually done three to four weeks prior to the date that the target (to be pollinated) plants will be ready to pollinate. Response times may vary slightly depending upon the strain. More specific times can be determined by trial with your own individual strains. In my trials it took 26 days for the first pollen. 30-35 days seems optimum for planning purposes.

So, assuming that a target plant needs 3-4 weeks to produce fully mature seeds, a strain that takes 8 weeks to mature should be moved into flower at about the same time as the female>male plant. A target plant that finishes flowering in 6 weeks needs to be moved into flower later (10 days or so) so that it doesn't finish before the seeds can fully mature.

A seeded individual branch can be left to mature on a plant for a bit longer, while harvesting the other seedless buds if they finish first. Just leave enough leaves on for the plant for it to stay healthy.


Within days I noticed a yellowing of the leaves on the F>M plants. This effect persisted for two weeks or so; after this they became green again, except for a few of the larger fans. The plants otherwise seemed healthy. No burning was observed. Growth stopped dead for the first ten days, and then resumed slowly. No stretch was ever seen. After two weeks the F>M plants were obviously forming male flower clusters. Not just a few clusters of balls, but complete male flower tops. One plant still formed some pistillate flowers, but overall it was predominantly male.

It is strange indeed to see an old girlfriend that you know like the back of your hand go through a sex change. I'll admit that things were awkward between us at first.

When the F>M plants look like they may soon open and release pollen, ( 3-1/2 to 4 weeks) move them from the main flower room into another unventilated room or closet with lighting on a 12/12 timer. Don't worry too much about watts per square foot; it will only be temporary.

When the pollen flies, move your target plants into the closet and pollinate.

A more controlled approach is to isolate the F>M plants in a third remote closet (no light is necessary in this one, as they are releasing pollen now and are nearly finished anyway). In this remote other closet the pollen is very carefully collected in a plastic produce bag or newspaper sleeve and then brought back to the lighted closet, where the target plants are now located. If this is done, be careful to not mix pollen types by letting the F>Ms dust each other. Avoid movement, or use yet another closet.

Take special care to not let pollen gather on the outside of this bag- a static charge is sometimes present. Drop small open clusters of blooms inside and then close the bag at the mouth and shake. Important: next, step outside and slowly release the excess air from the bag, collapsing it completely, so that pollen doesn't get released accidently. Point downwind; don't let it get on your hands or clothes.

This collapsed pollinated bag is now very carefully slipped over only one branch and is then tied off tightly at the mouth around the branch stem with a twist tie or tape, sealing the pollen inside. Let the bag inflate slightly with air again before sealing it off, so the branch can breathe. This technique keeps the entire plant from seeding. Agitate the bag a bit after tying it off to distribute the pollen. Don't forget to label the branch so you know which seeds are which. Other branches on this same plant can be hit with different pollen sources.

If no lighted closet is available, the plant can be moved back into the main room, but- be very careful: pollen is sneaky. After 4-5 days, the bag is gently removed and the plant completes it's flowering cycle.

Yet another method has worked well for me. I position the target plants in a non-ventilated lighted closet, and then I collect pollen on a piece of mirror or glass. This is then carefully applied to the pistils of one pre-labeled branch by using a very fine watercolor paintbrush. Care is taken to not agitate the branch or the pollen. No sneezing. The plant needs to be in place first; moving it after pollination can shake pollen free and blow this technique.

Regardless of technique, at completion you will have feminized seeds. Let them dry for 2-4 weeks.

About the chemicals:

Silver nitrate is a white crystalline light-sensitive chemical that is commonly used in photography. It is also used in babies' eyes at birth to prevent blindness. It can cause mild skin irritation, and it stains brown. Avoid breathing. I didn't notice any smell or fumes, but ventilation is recommended. Be sure to wash the spray bottle well before you use it elsewhere; better yet: devote a bottle to STS use. A half gram is a surprisingly small amount; it would fit inside a gel capsule.

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RE: STS Silver Thiosulfate Breeding

in Breeding Sun Nov 24, 2013 9:31 pm
by ozzydiodude • The Weird One | 2.084 Posts | 10103 Points

Born2killspam post

Colloidal silver works exactly the same way, but is way easier to obtain since you can just make it via electrolysis using any pure silver item as the anode..
I know a guy who did it successfully just winging it, but I don't know any specifics on his concentrations..
It probably wasn't very strong though, because I know his rig ran at 12V, and he had a separation of over a foot in distilled water.. (Actually, I can't even confirm that.. I don't know if he understands the difference between distilled/RO water, and RO would be more available to him)..

Masrproducer post

very true Born2killspam, I am actually working with CS, now, i will be putting up a totorial for that asap, as it is so easy to make, but yet so very effective and a lot safer and easier on the plant.

All you need is a 12v adaptor, alligator clips and 2 pieces of 99.9% pure silver, it can be wire or a coin or whatever, it is truly awsome


Its incredible similar to electroplating (making the solution).. In fact if you were to just google how to electroplate something, and then disregard the extra chemicals the tutorial said you needed for the electrolyte and merely use water, you'd be well on your way..
Step by step ghetto approach:
Get a wall adapter 7.5-12V perhaps.. (higher volts will work faster)
get a plastic container, and put some water in it..
Attach something stainless steel to the negative wire.. (Stainless steel isn't critical, but a decent choice)
Attach something silver to the positive wire..
Put the electrodes you attached to the wires in the water.. Make sure only silver parts are submerged on the positive side or else you will liberate other metals into the solution..
Power it up and run it for a few hours to a day maybe.. There are alot of variables here including voltage, electrode surface area, electrode separation, and the ionic content of the water.. While its electrolyzing you want to see some bubbles forming at the electrodes, so tinker with the separation distance, then let it do its thing..

I'm really not sure what the best approach to this is.. Purist results will come from distilled water, but that will take waay longer due to its horrible conductivity.. Salt/Vingar/pH Up&Down etc or even tap water would increase the conductivity and you'd get more bubbles and faster results, but the extra ions may cause problems..
Then again this is basically for plant torture, and purity may not matter at all, only the presence of silver ions.. The fact that the silver thiosulfate synth for this application doesn't need to be pH monitored during preparation means that it likely doesn't matter too much what else is floating around in there.

Massproducer post

i have never heard of using stainless steel wire, only silver, on both the negitive and positive, that is the way i make it anyways, like I said I have never heard of using stainless steel, as I think this would contaminate the cs solution, as there should only be silver dissolved in the solution
born2killspam post

I can see the actual ppm of silver in solution being an issue.. Silver doesn't have an exteme electronegativity, so it won't really get bound to anything so tightly that it can't react with other things..
A pure (ionic) colloidal silver solution would be distilled water with a bunch of Ag+ ions and some microscopic particles of elemental silver.. The difference between those opens a whole other can of worms, but like I said, I've seen success using an ionic solution..
The synth you posted would also create an ionic solution, but obviously it would also contain sodium nitrate, and its ions..
Therapeutic colloidal silver though is supposed to contain more elemental silver..

Massproducer post
See that is something that you can not do, you can not compare STS to CS because they are totally different substances, and as such they work in totally different ways.

CS work by adding pure silver ions which in turn disrupts the ethylene pathways causing male flowers. This is why it is a rquirement to use RO or distilled water when making CS, as the other metals will contaminate the solution if using tap water.

STS works not only by silver, sts is a chemical and as such chemically alters the ethylene pathways.

Comparing the two is like comparing apples to oranges

When of the major benefits of CS, over GA3 and STS is that it is not hard on the plant and it doesn't contaminate the plants, a plant treated with CS may still be consumed, when a plant treated with STS or GA3 is basically worthless other then the seeds you harvest.

born2killspam post

That silver will separate from the thiosulfate ion pretty readily.. And when it does its going to be ionic Ag+, not elemental Ag.. The biology of the hormone disruption I'm not particularily versed on.. Can't argue with results though, I've seen ionic electrolyzed Ag+ herm out a plant exactly like it should..
Have you ever played with the light cycle 5.5h-1h-5.5h? During the start of flowering? I've heard success with that too.. Really it doesn't matter how you herm the plant, as long as it resists the herm more than its peers.. An easy to herm plant just doesn't carry ideal genes to start a feminizing campaign..

massproducer post

yes I have have tried and research basically all methods, but like soma's method of rodelization, light poisining is not really efficienct in producing enough pollen to make the whole thing worth while, IMO and experience.

As I said STS and CS are totally different and I would have to disagree that it doesn't matter how the male flower is achieve. I intentionally stress my plants to weed out the weak and intersexed. So if a plant hermies easily under light poisining, ph stress, drought, or any enviromental type of stress, that is a plant I would not use for breeding purposes. The plant could make a wonderful mother, but for breeding purposes you are starting with inherent weakness and farther weaking the genes by forcing the reverse.

born2killspam post

I wasn't implying that it was ok to select an easy to herm candidate, just that the method is irrelevant once you've selected your resilient candidate..
How much detail have you come across regarding the actual mechanism that may be at work here? I know the silver serves to displace copper, which does interfere with ethylene migration, but I can't find much specifically beyond that..
Silver though is pretty much the primary catalyst for ethylene oxidation in industry..

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