Proper storage techniques of cannabis seed result in higher germination rates and improved seedling vigor.
Storing cannabis seed correctly has a beneficial effect on germination and the subsequent health and vigor of the seedlings. Growers may exploit the advantages of starting their marijuana plants by seed simply by using reliable storage methods that lead to high germination rates and protection of genetic integrity.
“Dark, dry, and cool are the environmental objectives for proper storage but precise care and control can further help insure the health and life span of cannabis seed for successful cultivation of good quality crops.”
As a grower starting with seed, you’ll be investing in a seasonal crop, so be sure to select strains that are best for your cultivation method and location.
Most cannabis growers who start with a seed obtain their stock directly from breeders or from seed banks that offer a wide selection of various strains for most culture methods. Many plant that seed soon after receipt and do not require long-term storage solutions. Even so, methods of seed storage and handling, even for short periods, affects their health. Although seeds are in a state of rest, or preservation until conditions are conducive for germination, they are alive and vulnerable to harmful conditions; even between shipping and planting.
Many seed banks offer their products to an international market, so the selection is huge. (Check laws and regulations regarding seed purchase and sale for your location; they change regularly. The responsibility for compliance is on the purchaser since seed merchants rarely accept liability as the legalities of the seed are likely beyond their control.) On a local level, breeders offer their product lines to dispensaries and retail establishments approved for legal sales, or at trade shows and cannabis events. While industrial hemp seed for plants with no THC, typically sells by weight or volume, cannabis seed for cultivating medically or recreationally consumable crops sells per individual seed, although sometimes the weight of large quantities is a method for estimation of quantity.
Street for cannabis seeds: "beans"
Retail lot sizes typically start with 3 (three) 5 (five) or 6 (six) seeds and increase incrementally in quantity from there, with lower pricing of bigger amounts. It is common for large growers to contract with seed companies for negotiated prices and terms, so contact several for availability when shopping if you are in that market sector as a commercial grower or need more than 100 (one-hundred) of one strain. As a rule, seed vendors are reliable, excited about their product and most are willing to work with you with discounting if they can. Some also offer warranties or guarantees of germination; a factor to consider when comparing sources.
Cannabis Seed Specifications
• 1 cannabis seed weighs 0.01 to 0.02 grams
• A seed contains the genetics of both parents
• Auto-flowering strains bloom by plant age
• Feminized seeds develop into female plants
• Store seed in darkness in an airtight jar
• Safe Storage Temperature: 39.2 ˚F (4.0 ˚C)
Minimum: 33˚F (0.55 ˚C)
Maximum: 72˚F (22.22 ˚C)
• Safe Storage Humidity (rH): 6-9%
• Labeling regulations for selling vary by location
Every authority has differing regulations pertaining to packaging, labeling, and tracking of cannabis seed, so make certain to follow the law pertaining to purchase and distribution for your location or permit. Record keeping is important for your own operation, but also for regulatory agencies that may require information pertaining to strain types, sources, dates, lot numbers, quantities bought and sold, etc.
The more detailed and complete your records are, the better, even if most of it is for internal use.
Packaging varies by the seed bank, but most containers are glass or medical grade tubes; some are opaque. As temperature, a factor influencing seed viability, is changeable during shipping, growers minimize this risk by starting the germination process soon after delivery or procurement of seed, and plan accordingly. For those who hold the seed for longer periods, proper storage conditions are necessary.
A reasonable expectation for germination from a reputable seed supplier or a bank is around 85-90%. The time of year for ordering and transportation does not affect the germination rate from variables of the season, except for high humidity, and high temperature; the length of time in transit does. Cannabis seed exposed to changing conditions and wide environmental swings for extended periods will usually lead to a decreased germination rate. Fast shipping methods are useful and worth any additional fees.
For growers that also conduct selective breeding for seed production, after removal of all leaf and plant material, seeds benefit from a drying period in relative darkness before storage. The process must be gradual and thorough; not to zero percent (0%) moisture, but to about six to nine percent (6-9%). Food-safe desiccant packets are helpful in this process; follow the manufacturer’s directions for use.
It is very common to have more seed than needed for planting, especially if you take advantage of pricing discounts for larger quantities at time of purchase. You may also receive free seeds from banks that offer promotional offers, or have seed from trade shows. The most important principle in cannabis seed storage is to keep environmental factors at a static, unchanged level. Rapid swings in temperature, humidity, or light exposure will have an adverse effect on cannabis seed and drastically effect germination rates.
The ideal container is the starting point to good storage practices. Your goal is to maintain the integrity of the seed and protect it from insects and rodents. Glass, plastic, or metal containers provide the best protection, and these types of containers specifically designed for seed storage are the best. Some cultivators use a food-safe silica gel packet to maintain optimal humidity; this method requires adequate space in a container for both the seed and packet. Your local hydroponic store or the Internet offer useful seed storage solutions, including jars, vials, and tins.
Make certain to label everything with strain and date of storage. Professional breeders go overboard with labeling and for good reason. Unless you are sure of what you are planting from a seed, you may as well consider it “bag seed” if you are a serious grower. Minimally, the label should have the strain name and date you put the seed into storage.
Where the container resides with the stored seed is the next most important factor in best practices for storage. Choose a place that is dark with very little change in temperature. Often, this is in a closet or pantry with little or no fluctuations in climate or lights. Be very careful with the use of refrigeration. While it is possible to extend the practical life of seed with the placement in a refrigerator, the risk from condensation is high and very dangerous to stored seed. While some literature suggests the use of a freezer, this is a risky location and it is not prudent for desirable germination rates. The risk from the likelihood of cellular rupture in freezing temperatures is too high to jeopardize the viability of valuable seed.
Cannabis seed has a finite lifespan, so the most prudent advice is to use it for planting promptly after acquisition. For best results, do not store cannabis seed for longer than 6 (six) to 8 (eight) months, and purchases the seed close to when you anticipate planting.
Nature is amazing, and you will hear and read reports of cannabis seed that is twenty (20) years old with successful germination. While that is not the norm, and maybe some exaggeration, growers can generally expect properly stored seeds to have ninety percent (90%) germination after two (2) years of ideal storage. After about five (5) years, cannabis seed may only have a thirty (30) to fifty (50) percent germination rate, even under perfect storage conditions.
As there are so many variables that effect the viability of cannabis seed, it is not wise to invest in large quantities that will not go into cultivation within a year. Except for breeders that protect genetics of certain strains, proper long-term seed storage requires protocols that are not best suited for most growers. Short-term storage is more practical, and selecting fresh, and viable seeds at the start of a growing season are the most successful ways to have high germination rates of new and desirable stock.
While many growers begin with clones for production farming, there are benefits from starting a crop by seed or for propagating mother plants from seed for cloning. If your cultivation work flow involves cannabis seed, protecting it, and storing it properly will produce the most desirable results. For specific details or questions, always reach out to your seed producer; they want you to succeed and are a great resource to connect with.