If your mail box is outside and there is critical daytime frost put your delivery in a refrigerator immediately to thaw slowly. Frozen seeds can be damaged and may fail to germinate. If possible, arrange for your mail to be collected at the post office or delivered to your door.
Seeds are best stored long-term in a cool and dry place. A refrigerator at 5-8°C/41-46.5°F is ideal. Do not freeze the seeds as they may be damaged when they thaw. Place your seeds in a zip bag and small tupperware box to ensure that they remain dry. You can also put some rice or a bag of desiccant into the tupperware box to absorb any accidental moisture.
Mandala seeds can remain viable for 3+ years with little or no loss in germination. This is a biological product and we cannot predict or guarantee the length of viability.