What are the best ways to store garden seeds in our homes? Is the fridge a good option? Let’s look at the conditions seeds need to remain dormant yet viable for future sowing.
If you are new to starting plants from seed, Seed Starting for Beginners have everything you need to know to get started.
Storing Seeds at Home
We know seeds can last longer if stored properly but what does this mean for keeping seeds in our homes?
The goal is to keep seeds dormant (not growing) but viable (capable of it).
The good news for gardeners is the normal conditions in our homes tend to be fine for short-term seed storage. By “short term” we mean a year or two.
Some seeds will certainly remain viable longer than this, but, generally, a lot of common seeds (e.g. annuals including vegetables) have peak germination rates in the first few years and begin to wane after that. You can still sow them but you’ll likely need to sow extras to make up for the decline, and the older the seed, the less likely it is to sprout.
The main factors affecting seed storage success are moisture, temperature, and light.
If you can keep your seeds dry, in average household temperatures or lower, and away from light, your seeds will store just fine.
While the fridge is certainly an option, but, if it’s just for a year or less, that lower temperature won’t make much difference. For longer-term storage, it can help.
- Seed Storage Tips
- Best Temperatures
Seed Storage Tips
Optimum Seed Storage
The lower the temperature and moisture levels, the longer most seeds stay viable.
Best temperature | 32-41°F (0-5°C)
Most fridges are in this range.
Also, room temperature (70°F/21°C or lower) is fine for short-term storage (1 year).
Store dry seeds and keep dry | Relative humidity below 50% | Keep away from light.
If moisture is an issue, use silica gel pack in containers.
While long-term seed storage units like they have at the Global Seed Vault require special conditions we cannot provide at home, basic seed storage for home gardeners is much simpler.
This is because even in less than optimal conditions, seeds tend to remain viable for their first few years.
As gardeners keeping seeds at home, this means average household conditions are generally good enough to keep a pack of seed fresh from one year to the next. And sometimes longer.
Location in Your House
Common storage locations include:
Again, the actual location doesn’t matter—the conditions (moisture, temperature, light) do.
In the short term, any differences between storage methods are likely minor.
If we’re just storing seeds until next spring and maybe even the year after, your seeds will store best with:
- moderate temperature or lower (more on this below)
- moderate or lower humidity (the lower, the better)
Knowing that viability diminishes over time, I keep my seeds sorted by Best Before date to be sure I use them up in the right order.
You’ll also want to choose a location where any critters like mice can’t get them.
That said, some seeds just don’t store well no matter what you do. Your seed packet will likely list special instructions if any special storage conditions are best.
Harrington’s Rule—Storage Temperature Matters
In the world of botany we have Harrington’s Rule for seed storage.
The cooler and drier, the better.
Not all seeds, but generally storage life:
- Doubles for every 10-degree Fahrenheit (5°C) drop in temperature and also
- Doubles for every 1% drop in seed moisture content.
We probably aren’t going to do much about the moisture content of our leftover seeds, nor will we have a way to measure it, but temperature is something we can usually manage by choosing a cooler room in the house.
Room Temperature Versus Fridge
Your typical room temperature is around 70°F (21°C) and your fridge is around 40°F (4°C), so that 30-degree difference should significantly extend the life of your seeds over the long run.
But, in the short-term (a year or so with fresh seeds), it doesn’t make much difference.
If you do choose the fridge, use airtight containers to prevent moisture from getting in.
Freezer Storage Pros and Cons
With seed banks, their standard storage temperature is around -18°C or just under 0°F which also happens to be the temperature inside many home freezers.
So the freezer may seem like an even better place to store your seeds—and it may be if you are planning to store the seeds for many years—so long as moisture levels are low.
The natural cycle of most seeds we grow is to mature and dry out. Their metabolic rate lowers and they stay dormant until germination is triggered.
One group that cannot tolerate cold or freezing conditions includes seeds from tropical trees, which are usually quite large seeds (think avocado), so check if you are uncertain. These retain higher moisture levels causing them to ice up and die when temperatures are too low. So exclude this group.
Otherwise, you can use the freezer for long-term storage if you are confident moisture levels will remain low.
I only use the fridge and freezer for seeds like delphiniums that require a moist chill period prior to sowing. That’s really a germination trick, not a storage tip.
And there you go.
If your home has stays around 70°F (21°C) or less, with moderate or low humidity levels, and the seeds are kept dry in darkness, they will store just fine for a year or two.
The fridge or freezer (if moisture levels are not an issue) can be helpful for longer-term storage.
Seed Viability Test
- How To Check If Seeds Are Viable | Step-by-Step Germination Test Instructions
- Getting Started With Seed Saving (Flowers, Fruit, & Vegetables)
- Clever Seed Saving Tip For Best Results
- Vivipary: When Seeds Sprout Inside Fruits Like Tomatoes
- How to Save Heirloom Tomato Seeds
- How to Harvest Zinnia Seeds
- Best Soil Temperatures For Sowing Vegetable Seeds
- Empress of Dirt Printable Garden Planner (includes seed inventory sheets)
- Printable Plant Name Labels for Organizing Seeds (& More)
~Melissa the Empress of Dirt ♛