Let’s say your marijuana seeds arrived in the mail earlier than expected, or maybe you’re not just ready to start growing them. You might be worried that your weed seeds will spoil or go back—but have no fear! If you store marijuana seeds properly (and we’ll teach you how), they can last for months.

So, you found a place to buy marijuana seeds online and you took the plunge and ordered. Good for you! Now you eagerly run to the mailbox each day, heart all a-flutter, waiting for those magical seeds to arrive, and then suddenly — wonder of wonders — they’re here! It’s an exciting moment. But let’s say for one reason or another you can’t plant right away. Maybe you still need to set up your grow space. Maybe you’re planning ahead for when your current crop is harvested. Or who knows—maybe your Aunt Lulu is visiting and she thinks marijuana is the devil and you don’t want to alarm her. Never fear, intrepid grower: Your seeds should be ready to sprout whenever you’re ready for them—as long as you stick to a few simple storage tips.

How to Store Marijuana Seeds

Planting your seeds as soon as possible will only improve your odds of successful germination, but that doesn’t mean you can’t keep them viable for a long time—up to five years, and possibly longer. Some people report seeds remaining viable for more than a decade! Before contemplating your seed storage options, you’ll want to consider how long you plan to be putting them away. This will help you optimize your storage choice and make it easier to stick with it. Cannabis seeds don’t take kindly to many variations in temperature, so it’s best to be decisive and leave them alone until planting time.

Best Practices to Store Marijuana Seeds

The fundamental rule to follow is this: Seeds should be kept somewhere cool, dark, and dry. The ideal temperature is around 40 degrees Fahrenheit (or 5 degrees Celsius), and the ideal humidity is around 9%. You don’t want them getting too warm or too moist, lest they begin sprouting prematurely. If you’re just putting them away for a few weeks, a dark drawer or cabinet should be fine, provided the room doesn’t get too warm. (Let’s all take a moment to be thankful for the wonder of air conditioning.) If, however, you need to keep your seeds healthy longer-term, most experts recommend the refrigerator. You can empty out one of those produce drawers and create a seed repository—especially if it’s one that lets you dial the humidity down. It’ll keep them at the most consistent temperature, and protect them from excess moisture.

High and Dry

Since moisture is the enemy of effective seed storage, you want to keep the humidity as low as possible. To that end, some growers like to toss in a silica gel desiccant packet along with their seeds while they’re in storage. Silica packets are those little pillow-shaped things you sometimes find in vitamin bottles or shoes, where they’re used for the same reason: To absorb moisture. Don’t have any silica gel desiccant handy? You might also try tossing in a few dozen grains of uncooked rice.

Freezing Your Seeds: Yay or Nay?

Freezer storage is a real point of contention among growers. Some say it can hold seeds in stasis, extending their lifespan, while others are adamant that too much cold will damage them as surely as too much warmth with sprout them. This is one where you’ll have to read up and decide for yourself since right now there’s no consensus to be found; I personally think the fridge is a safer bet. Wherever you keep your seeds, you should seal them in a plastic bag and another external airtight container. A film canister is ideal since it’ll also protect them from light. If you can’t get your hands on one of those (who uses film these days?) a mason jar will work too, as long as you keep it somewhere dark. Make sure the jar is completely dry inside and out before you seal it up; the point is to avoid water as much as possible. And don’t forget to label your strains, so you’ll know what you’re growing!

Handle Your Marijuana Seeds With Care

When taking your seeds in or out of storage, here’s an important tip: touch the seeds as little as possible with your hands—preferably not at all. Oils from your skin can start to wear away the seeds’ protective outer shell, exposing the embryo within to oxidation. The best practice is to use a pair of tweezers to (gently) handle the seeds when needed. You needn’t take all the precautions they use at the Svalbard Global Seed Vault in Norway.

Not everyone can store their seeds 400 feet deep in a sandstone mountain (which, let’s face it, isn’t all that convenient). Just remember the mantra “cool, dark, dry” and your little treasures should be fine. When you’re ready to take the seeds out of storage and get growing, head on over to our comprehensive germination guide for the best techniques! And if you’re just getting a head start (you planner, you) and haven’t even bought your seeds yet, don’t miss our ridiculous selection of feminized, tested, and TLC marijuana seeds.