Choosing the right Mylar bags for seed storage comes down to thickness, size, and how well they protect against light, oxygen, and moisture. When you get these basics right, you can keep seeds viable for many years with minimal loss in germination.
Why Mylar Bags Work So Well
Mylar is an aluminum polyester film that provides a solid barrier against air, light, and moisture. This covering retards seed aging, molds, and pest protection much better than paper packets or regular plastic bags.
In long-term storage of seeds, the aim is to provide a low, dark, cool, and dry environment with low oxygen levels inside the bag. Mylar bags can preserve seeds in a state of readiness to be planted years later when combined with oxygen absorbers and (optionally) desiccants.
Choose the Right Thickness
The thickness of Mylar bags is quantified in mil (thousands of an inch) and has a direct impact on durability and protection against light.
2-3 mil: Good temporary storage or snacks; not very good long term storage seeds as they are less difficult to puncture.
4–5 mil: Hard middle ground of herbs, coffee and small food, can be used with seeds, but must be taken care of and kept in bins.
5-7 mil: Use where you need to store long-term items that require excellent light, moisture and physical protection.
7+ mil: A strong material commonly employed in large-scale storage or upright gusseted bags.
The most common bag size applicable to home gardeners is the 5-7 mil bag: not too thin to keep out the light and not so thick as to become difficult to seal and store.
Pick the Best Size and Style
Seeds do not require big and heavy bags. The smaller sizes are much easier to organize and rotate.
1-cup/small flat bags: This bag is perfect when you have a single variety or a small collection of heirlooms.
1/4-gallon or 6 by 9 inch bags: Ideally used to package large amounts of a single variety or seed blends.
Gusseted bags (stand-up): large when you need to store a lot of seeds or create an emergency seed bank.
When filling the bag, strive to fill it with the same amount of seed as the volume of the bag to create a small air space. This aids in the efficient operation of the oxygen absorbers and lowers the chances of moisture pockets.
Oxygen Desiccants and Absorbers.
The Mylar bag is half the batt, and the inside environment is as well. Oxygen absorbers eliminate the majority of oxygen and retard oxidation, mold and insect infestation.In order to contain moisture, desiccant (silica gel) is used particularly in humid climates. Approximately, one 300 c.c. An oxygen absorber per gallon of air in the bag is used as a rule of thumb, and a smaller amount is used when dealing with small seed pouches. Pairs of Mylar and oxygen absorbers with a small desiccant sachet provide seeds with the most stable environment in high-humidity regions.
Key Features to Look For
When comparing Mylar bags to store your seeds, observe the following characteristics:
Organic, BPA-free material to ensure the seeds can be used to produce a future food source.
Aluminum layer that prevents light through to protect the seeds (not transparent plastic windows).
Long term durability and barrier performance, 5-7 mil thick.
Top is heat-sealable so you can create an airtight closure using an iron or sealer.
Optional zip-lock strip to facilitate re-sealing the bag after use (convenient with seeds used more often).
When storing, always put the name of the variety of seed and the date on your bags. This is an easy practice and allows rotation and planning the following season garden much easier.
Storage Conditions Matter
Even the highest quality Mylar bags would not help to offset low storage conditions. In order to maintain seed life as long as possible:
Keep in a dry, cool and dark location, not subject to extremes in temperature or direct sunlight.
Do not use garages, sheds or attics where there is an alternation of heat and humidity.
Take into account a refrigerator or a cool basement where you can keep high-quality or rare seeds, and well-sealed Mylar and moisture control are essential.
One method is to store the seeds in Mylar bags with oxygen absorbers and then store those bags in a hardened container such as a bin or a bucket to provide additional protection against rodents and punctures. Give Pack Role’s puncture resistant mylar bags with complete customization a chance to keep your seeds fresh forever.
Through thickness, size, and quality of the barrier, and internal conditions, we can safely select Mylar bags that keep your seeds healthy and ready to sprout over many years to come. Customize mylar bags them today with Pack Role.
