After the whole process of germination, growth and flowering, a lot of growers ask themselves when to harvest Marijuana seeds. Usually, the breeders will include a suggested flowering time for each strain, but as a rule of thumb, Indica marijuana plants harvest in 6-8 weeks while Sativa Marijuana plants take 10-12 weeks.
If you meant when to harvest seeds from cross-pollinated Marijuana plants, then the seed will fall from the flower by itself once it is mature and ready to germinate into another Marijuana plant. Usually, as a best practice to harvest Marijuana seeds, some growers wait for the whole flowering cycle to end just as if they were harvesting the flower.
Look for these signs for when to harvest Marijuana seeds
You can also judge the ripeness of the Marijuana by taking a look at the trichomes; or little hairs/crystals on the flowers and surrounding areas of the Marijuana plant. If they are transparent its still too soon, if they are milky white they are ready and if they turn brown they have become over-ripe. It is also advisable to follow the instructions to harvest Marijuana seeds on the packet since most reputable breeders also have a tried and tested flowering time for optimum ripeness, potency and flavour of a Marijuana strain.
You might find our FAQ Submission How Do I Harvest My Plant? useful
You’re probably thinking: grow plug? Propagator? Root stimulator? What?! No worries: germinating is 100% natural. All cannabis seeds really need is light and water. Check out my preferred germination method here, or follow this grow guide to plant germinated seeds directly into the soil. Find out what works best.
My biggest mistake ever was leaving the lights on after flowering in the room where I set up my tent. Sadly, the tent wasn’t light-proof, so my plants got stressed out and turned into hermaphrodites. The result: a whole harvest full of seeds that was no use at all… Fourteen weeks of work down the drain! I also made the mistake of pumping out my entire 60L nutrient mix tank in one go once. Pretty bad for plants capable of handling 10 litres at once max…
Baby Steps: Germinating Your Weed Seeds
Well, you’ve made it: at this point, your cannabis plants are in full bloom! Some strains have a 7-week flowering phase, while other flower for up to 14 weeks. Decide what you want before you start. Keep a tight grip on your grow climate in the flowering phase. If it gets too cold, bud development stagnates. High air humidity invites bud rot, mildew, and other pests to ruin your harvest.
Once the seeds become seedlings, with roots showing on the sides and bottom of the grow plus (usually after about four days), they’re ready for planting. I start with small P9 size flower pots. I’ll leave them for 7 to 11 days to give the roots time to develop, creating a stable habitat.
With the lights off, drying net in place, and exhaust fan running at 50%, air humidity slowly drops. Your buds are dry as soon as bending branches makes them snap.
One common method is to stress the female by applying solutions like colloidal silver or silver nitrate generously onto the leaves when she first enters the flower light cycle. Within 3-4 weeks, male sex organs will appear on the nodes of the female plant. Please note, applying these stress-inducing solutions to plants renders them unsmokable. The particulate cannot be washed of thoroughly because it settles deep into the surface of the plant. This method is for seed production only.
Though many grow ops aim to do away with seeds to grow fine sensimilla instead, sometimes breeders want seeds. Whether to grow their own crops or to sell to a demanding public, cannabis seed cultivators have their goals set on producing healthy, happy seeds in lieu of big, beautiful buds.
Seed crops are harvested when the seeds are plump and dark, often with a tiger stripe appearance (around six to eight weeks into flowering). After harvesting, the bud is dried and the seeds are collected. Small-scale seed collection is done by simply crumbling the cannabis flower and collecting the seeds that fall out (this video by Johnnys Green Extractions offers a clever way to separate seeds from flower using an old vinyl record cover) while commercial seed collection usually involves special machines that crush dried flower then pass the trim and seeds into separate bins.
Natural Cannabis Seed Production
Another method is to simply let a healthy female age. If she grows past maturation, she will produce male “banana” pollen sacks without any male chromosomes. Though she may look like a hermaphroditic plant at this point (one containing the chromosomes of both male and female), the pollen she produces will contain only XX chromosomes and therefore cannot pass the Y (male) chromosome down to its heirs. Pollen collected in this way is then used to pollinate another female which will then produce female-only seeds.
T here was a time in our not-too-recent history when a sack of weed almost always included seeds. But as cannabis cultivation evolved, so did the demand for sensimilla, or high-quality, seedless cannabis. Breeders not only began developing their own customized strains, they also started specializing in the cultivation of very special cannabis seeds. These seeds are used in both the breeding process and the wide-spread distribution of the carefully created strain itself.
The process of breeding the perfect strain requires a controlled production of seeds. Breeders must force their favorite plants to produce pollen and then use it to pollinate other favorite strains, thus creating “cross-breeds” of their two selected parents. Note that this process is not haphazard like the seeds one might find in a poorly-controlled outside marijuana grow – cannabis seed cultivation is a precise process that requires controlled, sanitary environments that are thoroughly sealed to prevent outside dander from getting in.
After seeds are collected, they’re stored in opaque, air-tight containers to prevent them from rotting or sprouting prematurely. Though cannabis flower is usually cultivated to be seedless, sometimes the seeds are the whole point. Breeders pay special attention to the pollination, harvest time, and drying process when growing cannabis specifically for the seeds to improve the likelihood of a successful harvest.