# Pollination and seed production, step by step

> Pollinate females about 2-4 weeks into flower when stigmas are white and receptive, using fresh or stored pollen applied with a brush or bag to marked branches; seeds mature in roughly 5-7 weeks. Isolation is everything: pollen travels on air, clothing and fans, so a planned cross needs a separate space or strict bagging, and every pollination gets a dated record.

- Canonical: https://genetixbay.com/knowledge/breeding/pollination-seed-production.html
- Category: Breeding · Level: Intermediate
- Evidence: Supported · Status: Draft: awaiting expert review
- Stage: Flower, Ripening, Harvest · Systems: Any system
- Updated: 2026-10-31 · Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay Knowledge Base (genetixbay.com/knowledge)"

## Questions and answers

**When should I pollinate my cannabis plant?** Pollinate a cannabis plant when its [stigmas](https://genetixbay.com/knowledge/glossary/stigma.md) are fresh, white and upright, typically around weeks 2-4 of flower, within a receptive window of about weeks 2-5. Grower practice favours early to mid flower; pollinating too late gives low seed set and immature seed at harvest. Repeat after 3-5 days if coverage looks poor.

**How long do cannabis seeds take to mature after pollination?** Cannabis seeds take about 5-7 weeks to mature after pollination, based on grower practice. Keep the plant in flowering conditions throughout, and watch for [bud rot](https://genetixbay.com/knowledge/glossary/botrytis.md) because swelling seed pods hold moisture. Harvesting earlier tends to lower [germination](https://genetixbay.com/knowledge/glossary/germination.md), so wait until the [bracts](https://genetixbay.com/knowledge/glossary/bract.md) split and the seeds are dark and hard.

**How do I pollinate just one branch?** To pollinate one cannabis branch, dab pollen onto its stigmas with a clean, dry, lightly loaded watercolour brush, or slip a paper or fine-mesh pollination bag holding a pinch of pollen over the branch, tie it, shake gently and remove it after 24-48 hours. Tag the branch with the cross, date and pollen batch.

**How do I stop pollen from getting everywhere?** Stop [cannabis pollen](https://genetixbay.com/knowledge/glossary/pollen.md) spreading by keeping the male in a separate room or tent with its own air, turning [fans](https://genetixbay.com/knowledge/glossary/fan-leaf.md) off or low while pollinating, and changing clothes and washing hands and arms after handling males. Bag individual branches, then mist the plant lightly to knock down stray airborne pollen. Outdoors, parentage can't be guaranteed without bagging.

**How do I know seeds are ripe?** Cannabis seeds are ripe when the bracts around them split and the seeds are dark, either mottled or uniformly dark, and hard when squeezed. Pale green or white seeds are immature and germinate poorly. Dry seeded branches for 1-2 weeks, rub out the seeds, discard tiny, pale or cracked ones, then dry them about another week.

**How many seeds does one plant make?** How many seeds one cannabis plant makes depends on how much of it is pollinated and how well. Each [female flower](https://genetixbay.com/knowledge/glossary/pistillate-flower.md) holds one ovule, so it can make one seed, and a single pollinated branch typically yields dozens to hundreds of seeds depending on its size and coverage. Whole-plant pollination gives far more seed but raises pollen risk.

**Short answer.** Pollinate when the female's stigmas are fresh and white, typically weeks 2-4 of flower. Brush or bag pollen onto labelled branches, keep the room still for a few hours, then wait about 5-7 weeks until the seeds are dark, hard and the bracts split. Contain pollen ruthlessly and write down every pollination.

**Legal first.** Producing seed may require a licence or be prohibited where you live, even where growing is legal. Check local rules before starting.

> **House position: males are a necessity.** Real breeding needs real males, selected as carefully as the females. Males are encouraged and rewarded on GenetixBay, and a well-documented male line is a prized contribution. [Selfing](https://genetixbay.com/knowledge/glossary/selfing.md) is mostly frowned upon: it was historically an emergency measure to save a line, not a shortcut. GenetixBay holds the best breeding standards: snobby, and proud of it.

## What's happening

Cannabis is wind pollinated. A single male can shed enormous amounts of light, dry pollen that travels long distances outdoors (*Established*) [1]. Each female flower holds one ovule, so one pollen grain landing on a receptive stigma can make one seed. Pollen viability drops fast at room conditions [2], so fresh pollen or properly stored pollen matters.

## Numbers that matter

| Parameter | Typical value | Notes |
|---|---|---|
| Female receptive window | ~weeks 2-5 of flower | White, upright stigmas; best early-mid flower (*Grower practice*) |
| Male pollen shed | ~2-4 weeks after flip, cultivar dependent | Sacs open from the bottom up |
| Pollen viability at room temp | Hours to a few days | [2] |
| Pollen viability at 4 °C | Mostly lost within 1 week (stage dependent) | Mid-stage pollen kept ~22% germination at 21 days [2] |
| Seed maturation | ~5-7 weeks from pollination | Earlier harvest lowers germination (*Grower practice*) |
| Seeds per pollinated branch | dozens to hundreds | Depends on branch size and coverage |
| Seed storage | Cool, dry, dark; ~5 °C maintained germination for years [5] | See [seed testing](https://genetixbay.com/knowledge/breeding/seed-germination-testing-qc.md) |

## Step by step

### 1. Plan the cross
- Choose the female (seed parent) and male (pollen parent) and record both GB-IND or GB-CUT IDs. Convention: write **female x male**.
- Decide **whole plant** (more seed, more pollen risk) or **branch** pollination (keeps the rest [sinsemilla](https://genetixbay.com/knowledge/glossary/sinsemilla.md) for evaluation).

### 2. Isolate
- **Best:** a separate room or tent for the male, with its own air. Collect pollen there.
- Keep fans off or low during pollination. Change clothes and wash hands and arms after handling males.
- Outdoors, other growers' males (and hemp fields) can pollinate your plants. You cannot guarantee parentage outdoors without bagging.

### 3. Collect pollen
- Cut a male branch with opening sacs, place it on clean, dry paper in still air for 12-24 h, then tap and sieve. See [pollen collection and storage](https://genetixbay.com/knowledge/breeding/pollen-collection-storage.md).

### 4. Pollinate
- **Brush method:** a clean, dry watercolour brush, lightly loaded, dabbed onto stigmas of a tagged branch.
- **Bag method:** slip a paper or fine-mesh pollination bag with a pinch of pollen over the branch, tie it, shake gently, remove after 24-48 h.
- Mist the plant lightly afterwards to knock down stray pollen in the air (*Grower practice*).
- **Tag the branch:** cross, date, pollen batch.
- Repeat after 3-5 days for better coverage if needed.

### 5. Mature
- Keep flowering conditions. Stigmas on fertilised flowers shrivel within a few days.
- Watch for bud rot: swelling seed pods hold moisture.
- Seeds are ready when the bracts split and seeds are dark, mottled (or uniformly dark) and hard when squeezed. Pale green or white seeds are immature.

### 6. Harvest and clean
- Dry the seeded branches for 1-2 weeks, then rub buds over a screen. Discard tiny, pale or cracked seeds.
- Dry seeds further at room temperature in a paper envelope for about a week, then store cool and dry.

### 7. Record and test
- Record: parents, pollination dates, harvest date, seed count, viability test. On GenetixBay this is a **GB-BAT** batch record with a `pollination` event.
- Run a germination test before you share or sell any seed.

## Common mistakes

- Accidental pollination of the whole room from a single forgotten male or [hermaphrodite](https://genetixbay.com/knowledge/glossary/hermaphrodite.md).
- Saving seed from an accidental herm pollination. It carries the [herm tendency](https://genetixbay.com/knowledge/glossary/herm-prone.md); discard it.
- Pollinating too late in flower: low seed set and immature seed at harvest.
- No tags. Six weeks later you won't remember which branch got which pollen.
- Selling or gifting seed without a germination test.

## Evidence

- Wind pollination and pollen dispersal: *Established* [1].
- Pollen viability decline at room and fridge temperature: *Established* (cannabis-specific assay) [2].
- Receptive window, maturation time, bag and brush methods: *Grower practice*.
- Reversed-female pollen for [feminised seed](https://genetixbay.com/knowledge/glossary/feminised-seed.md): *Established* [3][4].
- Seed storage at ~5 °C: *Supported* [5].

## Sources

1. Small E. 2015. Evolution and classification of Cannabis sativa (marijuana, hemp) in relation to human utilization. Botanical Review 81:189-294. https://doi.org/10.1007/s12229-015-9157-3
2. Gaudet D, Yadav NS, Sorokin A, Bilichak A, Kovalchuk I. 2020. Development and optimization of a germination assay and long-term storage for Cannabis sativa pollen. Plants 9(5):665. https://doi.org/10.3390/plants9050665
3. Flajšman M, Slapnik M, Murovec J. 2021. Production of feminized seeds of high CBD Cannabis sativa L. by manipulation of sex expression and its application to breeding. Frontiers in Plant Science 12:718092. https://doi.org/10.3389/fpls.2021.718092
4. Lubell JD, Brand MH. 2018. Foliar sprays of silver thiosulfate produce male flowers on female hemp plants. HortTechnology 28(6):743-747. https://doi.org/10.21273/HORTTECH04188-18
5. Small E, Brookes B. 2012. Temperature and moisture content for storage maintenance of germination capacity of seeds of industrial hemp, marijuana, and ditchweed forms of Cannabis sativa. Journal of Natural Fibers 9(4):240-255. https://doi.org/10.1080/15440478.2012.737179