Leave a female plant on the light cycle for 10–14 days past its normal harvest date and, in many varieties, it will often (but not always) produce male flowers. Collect that pollen and use it on the same variety next cycle, and the resulting seed should be predominantly female (near-100% in practice), though occasional hermaphrodite or male offspring are possible. This is the Age Feminization Technique described in Organic Marijuana, Soma Style. The author developed it as an alternative to gibberellic acid and to the harsher stress methods he had used before. It is entirely mechanical, it requires nothing you buy, and it is a legitimate in-house propagation tool. It also raises a genetics question that anyone using it needs to understand before they build a seed line on it.
1. The underlying biology
The premise, stated directly in the book: feminized seed is produced by stress, not by genes. Under sufficient stress, many cannabis varieties can produce male flowers on a female plant. Plants vary, though, and some will not.
A female plant has no male sex chromosome to pass on, so pollen from its male flowers, crossed onto a female, gives offspring that are genetically female. In practice that means predominantly female seed, not a guarantee. For plant sex and hermaphrodites in general, see topics 192 and 290.
The author’s route to it is worth reading as method rather than doctrine. He had previously tried:
- Gibberellic acid, which he notes is not organic;
- Altering substrate pH to stress the plant;
- Deliberate overfeeding.
He describes all of these as relatively harsh. He grew the same varieties in the same conditions for many cycles. Over that time he observed that simply extending the flowering period by 10–14 days often produced male flowers. That is one grower’s experience with his own varieties, not a guarantee for every plant. He named the technique after a friend who helped him recognise it, hence “Rodelization.”
His framing of the male flowers is memorable and useful. He calls them emergency equipment that appears at the most stressed moment of the plant’s life. Many growers panic at the sight of one; the technique is built on treating it as a resource instead.
One practical observation from the book: female plants held past harvest for pollen collection usually do not set seed themselves, though occasionally they do.
2. Method one: collect, store, apply next cycle
This is the more involved route, and the one to use if you run multiple varieties.
- Extend flowering by 10–14 days past normal harvest.
- Cut and dry the plant.
- Once dry, remove it gently from the drying line.
- Cut off all the male flowers and put them in a zip bag labelled with the variety name.
- Store the bag refrigerated for up to 2 months. (The book’s figure; see section 6 on why weeks is safer.)
- Start the next crop immediately after collecting.
- When the new crop reaches 2½ weeks of flowering, take the bag out and pollinate.
The cost: the host plant’s main harvest is held 10–14 days past peak. It will be over-ripe and at higher risk of rot (botrytis).
Pollination procedure:
- Place each labelled bag next to the female plants of the matching variety, so nothing gets mixed up.
- Turn off all fans in the room.
- Use a fine paintbrush to take a little pollen from the bag and paint it onto a female flower.
- Repeat for each variety.
The author reports doing this successfully with ten different varieties in one room at the same time.
The detail that makes this practical: he pollinates only the lower buds. The top colas are left unpollinated and are harvested normally. You get seed and a usable harvest from the same plant. For anyone who has avoided seed production because it costs them a crop, this is the reason to read this article.
3. Method two: whole-room, single variety
Simpler, and appropriate when you run one variety:
- Put the plants that have produced male flowers in the same room as plants that are three weeks into flowering.
- Run the fans at maximum so pollen circulates through the room for several days.
- After six to seven weeks, you have mature seed that should be predominantly female. Occasional hermaphrodite or male offspring are possible.
Pollen containment warning: use this method only in a separate room with sealed doors. Expect it to pollinate anything that shares the airflow: other rooms, your own sinsemilla crop, and potentially neighbouring grows. Pollen travels on air, clothing and ventilation ducts.
This produces less seed than pollinating with a male plant would. The book’s stated purpose, though, is preservation of a particular variety, and for that it is sufficient.
4. What this is for
The book positions the technique clearly, and this article’s framing is the same:
- Preserving genetics. You keep a variety as seed rather than as a mother plant, which must be maintained indefinitely and can be lost to a single failure.
- Breeding without a male. If you want to cross varieties but have no male plant, pollen from a female of the same variety is a workable substitute.
- In-house propagation. Producing your own planting material rather than buying it.
It is not a route to a commercial seed product, and this article is not about buying feminized seed from anyone. The technique is a breeder’s tool.
5. The genetics question: read this before you build a line on it
Here is where an honest article has to go beyond the source.
The book presents male flowers on female plants as a benign, universal capability. What it does not address is whether selecting for plants that readily produce male flowers under stress propagates that tendency.
This matters because the entire method selects on exactly that trait. The plants that readily throw male flowers at day +12 are the ones whose pollen you collect, so their genetics go into your seed.
What the literature says.
- Punja & Holmes (2020) studied hermaphroditic marijuana inflorescences. Seedlings from seed produced on hermaphroditic inflorescences tested genetically female with a PCR-based sex assay. Seedlings from cross-fertilised seed showed roughly a 1:1 male:female ratio. Punja ZK, Holmes JE. “Hermaphroditism in Marijuana (Cannabis sativa L.) Inflorescences – Impact on Floral Morphology, Seed Formation, Progeny Sex Ratios, and Genetic Variation.” Frontiers in Plant Science 11:718 (2020). doi:10.3389/fpls.2020.00718
- A recent review in Plants covers the genetic basis of sex expression, ethylene and gibberellin signalling, and chemical inducers. It describes sex-expression instability as controlled by overlapping quantitative loci rather than a single genetic switch. Richards CD, Ryu BR, Gim GJ, Park SH. “Hermaphroditism in Cannabis sativa L.: Impacts, Inducers, and Industry Implications.” Plants 15(11):1643 (2026). doi:10.3390/plants15111643
What remains limited is multi-generation data. Punja & Holmes looked at one generation and at genetic sex. They did not track whether those offspring went on to throw male flowers under stress, generation after generation.
What can be said without overreach:
- Hermaphroditism in cannabis has both environmental and genetic components. Many plants can be pushed into male flowering by stress, but the threshold varies substantially between varieties and between individual plants. That variation is consistent with a heritable component.
- A standard concern in the breeding community follows logically from that: feminized seed produced from readily-hermaphroditic stock may produce readily-hermaphroditic offspring. The concern is widely held, but I have not seen it quantified across generations.
- The chemical alternative, silver thiosulfate (STS) or colloidal silver (see topic 1303), forces male flowers even on plants that resist stress. Its advocates argue that this avoids selecting for stress-sensitivity, but it is a chemical treatment, which is exactly what the author was avoiding.
My take: Rodelization is a legitimate and genuinely organic technique, and for preserving a variety in your own garden it is a good tool. If you are producing seed that other people will grow, you need to have thought about the hermaphroditism-selection question and be able to answer it. Do not wave it away. At minimum, track it: over several generations, record which plants threw males and on what day, and whether their offspring did the same. That kind of multi-generation record is still scarce.
A related caution: the book’s own account of an accidental hermaphrodite event, caused by a faulty timer, shows that unintended light interruption can trigger the same response. Make sure your other rooms are light-tight.
6. Practical notes for this region
Extended flowering and mould. Holding a plant 10–14 days past ripeness in a humid climate substantially increases botrytis risk. A plant that rots from the inside will destroy the male flowers along with everything else. If you are running this technique in Southeast Asia:
- Choose a variety with looser bud structure for the seed plant if you have the option. The book gives the same advice for outdoor variety selection.
- Maximise airflow through the lower canopy, where you will be pollinating anyway.
- Consider running the seed plant in a separate, better-ventilated space rather than holding a whole bed past harvest.
- Reduce watering in the extension period, consistent with the book’s general end-of-flower advice.
Pollen storage. The book stores male flowers refrigerated for up to two months. Treat that figure as optimistic. Cannabis pollen viability in storage is variable. One study found that longevity differed with the growth stage at which pollen was collected, and its long-term storage method relied on vacuum desiccation and liquid nitrogen rather than a household fridge (Plants 9(5):665, 2020). Store thoroughly dried material in an airtight container with silica gel desiccant, refrigerated, and plan to use it within weeks rather than months.
Note that the book stores whole dried male flowers rather than sieved pollen. That is more forgiving of handling, but the flower material can mould in storage. Sieving out plant material before storing the pollen is worth doing.
Labelling. Not optional. Put the variety name and collection date on every bag. The whole method depends on not mixing up which pollen goes on which plant.
7. Checklist
- Choose the plant. It should be healthy and the variety you want to preserve, ideally not a dense-budded one if humidity is high.
- Extend flowering 10–14 days past normal harvest. Reduce watering. Watch for rot, and accept that this plant’s main harvest will be past peak.
- Cut, dry, remove gently.
- Cut off all male flowers, sieve out debris, bag, label with variety and date.
- Airtight container with silica gel, refrigerated. Use within weeks.
- Start the next crop immediately.
- At 2½ weeks of flower, turn the fans off and use a fine brush to pollinate lower buds only. (Method two: sealed separate room only.)
- Harvest the top colas normally; harvest seed from the lower buds at maturity.
- Record which plants threw males and when. Over generations, this is the only way to know whether you are selecting for stress-sensitivity.
Has anyone here tracked hermaphroditism across generations of a Rodelization-derived line? Multi-generation data on this question is limited. If you have run three or more generations and recorded when (or whether) males appeared, please share it in Breeders Lab (topic 247). That would be genuinely useful information for the community.
Related topics: STS and colloidal silver (topic 1303); hermaphrodites and plant sex (topics 192 and 290); Breeders Lab (topic 247).
This article is technical horticultural information for readers operating legally in their jurisdiction. In Thailand, cannabis is a controlled herb under the Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis) B.E. 2568. Cultivation, propagation and supplying seed to others may need permits, and the rules continue to change, so check the current requirements before you start. Elsewhere, producing, giving away or selling cannabis seed may be regulated separately from cultivation, or illegal. Nothing here encourages any activity where it is illegal, and nothing here is legal advice.