Seeds are best stored in a cool, dry, dark location. That basically describes a fridge. With one caveat. You can’t open the door all the time.
Incorrect storage can cause any number of issues all of which have the same result: your seeds will no longer germinate.
A glass jar is an ideal container, but your seeds may also already be in a great container. If you bought them online and had the seeds sent in the mail, chances are they are already sealed up tightly. Unless you need to open the container with the seeds, you can just leave them in there.
Plastic is not the best material for storing weed seeds, because it has microscopic pores that let in some of the outside environment. They work fine for shorter term storage, but if you are planning on keeping your seeds in storage for a longer period of time, you should avoid plastic.
As mentioned, it is very important to maintain steady environmental conditions. Fluctuations in temperature, humidity, light levels or oxygen levels all reduce the shelf life of your seeds. Furthermore, exposure to the external environment can also allow pests or harmful microbes to enter and damage the seeds.
You could also bury your seeds underground. This may seem strange, but if you go down deep enough that changes in air temperature don’t affect the ground temperature, this is actually a great storage location. You’ll definitely want to use desiccants to keep the humidity steady. And, of course, make sure you remember where exactly you buried them.
If you plan on storing a lot of seeds, it might be worth investing in a vacuum sealer. Then you can vacuum seal them inside a small container and place that inside a larger one like a glass jar.
Environmental factors that affect the viability of cannabis seed are:
Not all of the seeds that you purchase always end up in the ground for planting the season that you purchase them, which means the left overs require storage. However, if they aren’t stored correctly, you risk losing that seed to environmental factors that could affect your crop – or maybe it won’t grow at all. This article is about how to correctly store your seeds until next season.
Keep cool, keep dark, and keep dry! Maintaining a constant environment with little or no fluctuation is vital to ensure the stability your stored seeds.
Cannabis seeds are the orthodox type, or desiccation-tolerant, and can be prepared for long-term storage without risking instability.
There are two types of seed categories:
It is important to dry your seeds gradually and thoroughly before storing them—although not to 0% moisture, as this can result in the death of a seed. During ripening and drying, cannabis seeds will prepare for dormancy by slowing or stopping most physiological processes. Ideal moisture percentage is 2-3% and can be achieved by placing a desiccant in the storage container with your seeds. (A desiccant is a hygroscopic substance that induces or sustains a state of dryness in its vicinity (draws out water). Commonly found pre-packaged desiccants are solids that adsorb water, e.g., silica gel packs. These can be found at Wal-Mart, Uline.com, or your local florist!). Rice is also known to be an effective desiccant, but should be replaced periodically. The use of a desiccant when drying seeds greatly improves their stability.
So you’ve just received your latest shipment of 25 seeds from your favourite seed bank—and you only plan to plant 5 or 10 of them this season; or you’ve just finished this season’s harvest and you’d like to store the seeds you’ve collected for your next crop … Proper storage of cannabis seeds is an essential aspect of ensuring the viability of future marijuana crops.
Recalcitrant seeds can often be recognised morphologically because of their large size and smooth tegument. However, other seeds with a more normal appearance could also be recalcitrant. In the Mediterranean area they are not very spread but they can be found in woody species, climactic or not (Quercus, Castanea) or in riverbank species (Populus, Salix). In the rainforest, the species with recalcitrant seeds are dominant. Ecologically, they follow a strategy of lasting as seedlings, better than as seeds. That means that their seeds avoid getting too dry in a humid environment, where the very process of drying would be more difficult. Their lifespan is generally short, between a few weeks and 2-3 years.
When dealing with ultradry seeds, enormous savings of energy can be made by avoiding the use of too low temperatures during storage. Temperature may be the key factor when seeds are merely dried but it loses relative importance for ultradried seeds (Pérez-García & al., 2007). Independently, very low temperatures, close to that of liquid nitrogen (-196 ºC), provide an alternative method for the preservation of seeds and tissues (cryopreservation) that might play an important role in the future, especially for recalcitrant material.
1.The test tubes must be made of alkaline glass. This can be asserted through some greenish colour in their rim. Other glass types might soften more slowly or can even crack when heated.
2.Since long term preservation is intended, it is wise to place inside an internal label with the accession number, because any external label could get deleted or lost after a time. The number is easily written with a ballpoint pen on the sticky side of a label and then pressed against the wall with a rod.
3.The seeds, already clean and dry, will be introduced from another tube or by means of a funnel. Although it is possible to fill up to 8 ml, a less quantity is often placed in order to have more vials available when it becomes necessary to break one in the future. Rubber stoppers in Figure 5 are intended to avoid provisionally moisture intake from the outside.
4.A piece of cotton, preferably hydrophobic and previously dehydrated will be used to separate the seeds from the silica gel which will be placed on top.
5.Afterwards, approximately 3 ml of dehydrated silica gel will be added. Before moving on to the next step, it is advisable to place a rubber cap on the tube and wait for 15-20 days. If the seed is not properly dry, this will be shown in the bottom of the gel and simply changing this gel could be enough to take the sample to the desired moisture balance.
6.Another piece of cotton, like the one used in (4), will help to keep the whole in place. Around 5 cm of the tube should be left free, to allow sealing it by heat.
7.A numerous group of tubes can then be placed (convenient) for 24 hours within a box which is filled with CO2. Any other inert gas could do the job but CO2 being heavier that air may be managed more easily. Cylinders with dry CO2 are easily obtained from the market. 8.The flame from a standard laboratory burner may not be enough for a comfortable sealing of the tube. Therefore, a second entrance hole will be useful to apply a stream of oxygen or air. The current supplied by a standard house hairdryer could be enough to stoke up the flame.
9.The sealing itself can be done reasonably quick once some practice has been acquired. Holding the tube by its base with the fingers (no heat is felt) and with a long tong on the upper rim, concentrating the flame action and turning to spread the heat around, approximately 100 vials per hour can be thus closed.
10.Immersion of the sealed vials in water for 24 hours, would allow to check if any of them was not properly closed – the silica gel will change colour. The procedure should then be repeated for this particular case.
11.It would only remain necessary to add an external label with more data, according to the preferences of each bank, and to protect somehow the more delicate part of this set, the flame sealed tip. Both goals can be combined. A long, sticky label is rolled around the top and is used as a plank mould to pour inside a solidifying liquid.
12.Some substances were tried, such as melted wax, epoxy resins, etc. The conclusion reached was that the most practical solution consists of a mixture of wax (2/3) and pitch (= colophony or resin) (1/3) – this last substance used to harden the wax. The mixture is melted and poured with a dropper in the hole created by the label around the glass tip.
13.In order to avoid the top surface becoming scratched, a nail varnish could be applied.
When stretched with the flame and externally labelled, the vials should become of a final homogeneous size. In the UPM’s genebank they have traditionally been stored inside Kilner jars – long before finding that the last also were tight enough. Around 25 vials can be placed in each jar – thus obtaining a double security.
A third factor – the presence or absence of oxygen – has been the source of a contradictory literature over the years and, perhaps for this reason, it has largely been neglected from the practical point of view. However, recent research by Ellis & Hong (2007) suggests that ultradry seeds may be sensitive to oxygen; therefore, it is a factor that, at least tentatively, should be taken into account. Perhaps, the success of the UPM bank partly resides in the fact that air was originally substituted by CO2 in the atmosphere within the containers.
It should be noted that moisture content of 4-5% may be enough for the efficient conservation of some orthodox seeds such as those of many legumes (Ellis & al. 1988). However, as this author points out, these seeds do not suffer when ultradesiccated to 1-3%. In a genebank, with thousands of accessions being handled, the need to individualise the methods should be avoided. In this light, a general benefit to the use of ultradrying can be attributed – always speaking of orthodox seeds.
If we make an exception of those species growing in riverbanks, seed size seems to be a key factor to determine the orthodox or recalcitrant behaviour of a species. This is because mechanical damage produced during drying is more severe in large seeds. For example, the seeds of pumpkin (Cucurbita sp.) and of some Phaseolus species (P. lunatus) can be damaged through drying while the smaller watermelon seeds (Citrullus moschatus) or those from green beans (Phaseolus vulgaris) are orthodox. The internal composition could also set differences. When working with small seeds, it is possible to be fairly confident that they will be orthodox, whereas, with an increase in size, exploratory tests should be carried out.
To this date, the most commonly used procedure has consisted of drying the seeds with different procedures until reaching a moisture content of approximately 5-7%. After this, the seeds are placed in containers whose vapour tightness is most often untested and the success is mainly trusted to low temperatures. Ultradrying has been very rarely used, perhaps by no more than 50 banks – mostly of wild species in botanical gardens – out of more than 1 500 existing in the world. The UPM’s results have proved beyond doubt the efficiency of ultradrying in orthodox seeds at least under anaerobic conditions and also prove the comparatively lesser importance of temperature for ultradried seeds.