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When To Harvest Marijuana Seeds: Grower’s Guide

By Elton Platt January 6, 2025

Harvesting is a big deal and you’re wondering when to harvest marijuana seeds? It takes about 4-6 weeks for seeds to mature after pollination. This article will help you know when to check for seed viability and maturity.

Quick Facts

Check seeds around 4-6 weeks after the plant has been pollinated.
Variety of the plant; indica’s ripen faster than sativa’s
Check for firm seeds that have turned color and seed pods that are browning.
Adjust your harvest time based on indica, sativa or autoflower

Seed Maturity

Knowing when marijuana seeds are mature is key to growing. Seeing visual signs on a female plant and knowing the time after pollination helps you determine seed maturity.

Mature Female Cannabis Plant

Knowing a mature female cannabis plant is key to knowing when to harvest. A mature female cannabis plant will show several signs that it’s ready for seed harvest:

Full Height and Growth: The plant has reached its full height and stopped growing vertically. This is a clear sign the plant is putting energy into seeds and buds.
Yellowing Leaves: As the plant matures the leaves will start to yellow and fall off. This is a natural process and means the plant is near the end of its life cycle.
Dense Buds: The buds on a mature female plant will be fully formed, dense and compact. This is a sign the plant has finished flowering.
Pistil Color Change: The pistils (the hair-like structures on the buds) will turn from white to dark red-brown and curl in. This color change means the plant is mature and ready to harvest.
Trichome Development: The trichomes (the resin glands on the buds) will turn cloudy and amber. This means THC is present and the plant is at its peak potency.

By checking these signs growers can know when their female plant is mature and ready to harvest seeds.

Visual signs of seed maturity

You need to know when to collect your cannabis seeds. Check for these signs to ensure seed maturity and get the best results.

Seeds change color as they mature. They go from light to darker brown or even black. This means they’re ready to harvest.
Mature seeds have a hard shell. If you press them gently between your fingers they shouldn’t crush easily.
You may see the seeds start to pop out of the seed pods. This means they’re big enough and the pod can’t hold them anymore.
Seed size is a good indicator too. Mature cannabis seeds are about the size of a match head.
Another sign is the feel of the seed surface. It should be smooth and have a waxy coating, ready to store or plant.

Good seeds are key to growing and these visual signs help you identify them.

Once you’ve checked for these visual signs, move on to consider strain specific factors that may affect harvest time.

Time after pollination

After pollination cannabis seeds need a certain amount of time to mature. This is usually 4-6 weeks. During this time the seeds develop inside the seed pods on your cannabis plants.

They go through several stages before they’re ready to harvest. Keep an eye on them.

As the seeds mature they will show changes in appearance. These will be color and shell hardness. Each week brings them closer to being fully developed.

By watching for these changes you’ll harvest at the right time. Now we’ll cover the key signs for harvesting marijuana seeds.

Key Signs for Harvesting Marijuana Seeds

Harvest marijuana seeds when the seed pods start to brown and dry, that’s maturity. Also check the hardness and color of the seeds.

Remember to consider the whole plant when determining harvest time as techniques like cutting the plant at a certain height or soaking the whole plant in pollen can affect seed development and overall harvest.

Check Trichomes and Pistils

Checking trichomes and pistils is key to determining harvest time for your cannabis plant. These two will give you visual signs of the plant’s maturity and readiness for seed collection.

Trichomes: Trichomes are the tiny crystal like resin glands on the buds and leaves of the cannabis plant. They contain most of the plant’s THC and other cannabinoids. To check trichomes use a magnifying glass or a microscope. Trichomes will appear as clear, milky or amber. Clear trichomes means the plant is not ready yet, milky and amber trichomes means the plant is at its peak and ready to harvest.
Pistils: Pistils are the hair-like structures that stick out of the buds. They are white at first but as the plant matures they turn red-brown and curl in. This color change is a clear sign the plant is at the end of its flowering stage and ready to harvest seeds.

By checking trichomes and pistils you’ll harvest your cannabis seeds at the right time for maximum viability and potency.

Seed pods browning and drying

Seed pods browning and drying is a clear sign they’re ready to harvest. This happens because the plant is directing its energy to seed maturation and drying out the pods.

As these pods dry and brown cannabis cultivators need to keep an eye on them. It means the seeds inside have developed enough to survive outside the pod. Remove any plant material or debris to ensure seed quality.

Secateurs become essential tools at this stage for precise cutting without damaging the goods. Properly dried pods make seed cleaning easier and ready to store or plant now.

To prevent mold growth store these seeds in a cool dry place with silica gel packs to control humidity.

Hardness and color of seeds

When checking for marijuana seed readiness pay attention to their hardness and color. Mature seeds are hard to the touch and dark brown or tan in color. Seeds that are mottled or lighter in color still need more time to mature.

This visual check will ensure you harvest your cannabis seeds at their peak viability for growing and get high germination rates when you plant them.

Also understanding seed maturity is key to determining harvest time for marijuana seeds. As you check the hardness and color of your seeds these are your guides to know if they are fully mature before storing for long term or future growing.

Strain Specifics

Adjust your harvest time to indica, sativa or autoflower strains to get maximum seed viability and potency in your cannabis growing. Knowing the strain specifics will help you navigate the ever changing world of cannabis growing.

Harvest time for indica, sativa and autoflower strains

Indica strains mature in 8 weeks from start of flowering, sativa strains take longer around 10-16 weeks and autoflowering strains have a shorter life cycle and can be ready in 7-11 weeks from seed germination.

Growers need to pay attention to these times because harvesting at the right time is key to getting optimal cannabinoid and terpene levels.

These times differ because of the genetic variations between the strains. Indica plants have a shorter flowering period because they come from colder climates.

Sativa strains come from equatorial regions with longer growing seasons so they have a longer flowering stage. Autoflowering varieties have genetics that allow them to automatically switch from veg to flower without being influenced by light cycles or photoperiods like indica and sativa are.

Harvesting

Harvesting involves several steps to ensure your cannabis plant is ready for seed collection. One of the most important is stopping watering and nutrients.

Stopping Water and Nutrients

To prepare your cannabis plant for harvest you need to stop watering and providing nutrients at the right time. This allows the plant to focus its energy on ripening the buds and seeds instead of new growth.

Stop Watering: Stop watering the plant 1-2 days before harvest. Let the soil dry out slightly so the plant can concentrate its remaining energy on the last stages of seed and bud development.
Stop Nutrients: Stop providing nutrients to the plant 1-2 weeks before harvest. This flushing period will allow the plant to expel any remaining nutrients and will result in cleaner and more potent seeds and buds.

By following these steps you will be ready for harvest.

Harvesting in External Conditions

Harvesting in external conditions like weather and climate can affect the quality and quantity of your harvest. Knowing these and taking proactive measures will help.

Weather and Climate

Weather and climate is key to your cannabis harvest. Here are some to consider:

High Winds: Strong winds can physically damage the plant, break branches and reduce the overall quality of the harvest. To protect your plants use windbreaks or stake the plants to give them extra support.
Excessive Moisture: High humidity and too much moisture can cause bud rot, a fungal disease that can wipe out your crop. To prevent bud rot make sure there is good air circulation around the plants and use dehumidifiers if growing indoors.
Extreme Temperatures: Both high and low temperatures can affect the plant’s THC and cannabinoid production. High heat can stress the plant and cold temperatures can slow down growth. Monitor the temperature and use heaters or fans to keep the optimal growing environment.

By knowing these weather and climate conditions growers can take measures to protect their cannabis plants and get a good harvest even in harsh conditions.

FAQs

1. When to harvest marijuana seeds for maximum seed viability?

Harvest cannabis seeds during the flowering stage when seed maturity is at its peak. Observe the seed pods to determine this.

2. How to clean and store harvested cannabis seeds?

After harvest, do a thorough seed cleaning. For long term storage store them in an area with controlled relative humidity (RH) to prevent mold growth.

3. What are some tips for growing cannabis?

Cannabis growing requires control over lighting and moisture. Use grow lights for proper light and purified water and air conditioning for optimal humidity in your growing environment.

4. What’s the role of technology in modern weed farming?

Technology is big in today’s weed farming; from using heaters and dehumidifiers to prevent root rot to targeted ads on browsers and analyzing customer behavior online for better market reach.

5. Can I use cuttings instead of seeds for my cannabis plant?

Yes! Cutting is another way to propagate your cannabis plant besides using matured seeds that have been stored properly - think refrigeration or other methods that keep their viability intact.

Conclusion

You now know how to determine when to harvest your marijuana seeds based on seed maturity, key indicators and strain specific. Knowing these factors will help you optimize your cannabis growing and keep your seeds viable for long term storage.

By paying attention to visual signs, timeframe for seed development after pollination, seed pod browning and drying, seed hardness and color and harvest time for indica, sativa and autoflower strains; you can tackle this ever changing world with customized approach to harvesting.

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