Keep Your Garden Seeds Fresh from Year to Year with These 5 Storage Tips

After planting seeds in spring, many gardeners are left with lots of half-filled packets of vegetable, herb, and flower seeds, but there’s no reason to throw those old seeds in the trash.

Most seeds stay viable for at least a year or two after purchase. Some seed varieties can last for a decade or more with proper storage. Unfortunately, environmental factors such as temperature, humidity, and pests can all affect seed longevity and cause seeds to spoil faster than they should. By following these storage tips, you can avoid seed loss and keep your old seeds fresh until you’re ready to plant them.

How Long Do Seeds Last?

Seeds generally last at least a year after purchase, but some seeds spoil faster than others. Most annual flower seeds stay fresh for one to three years, while the germination rates of perennial flower seeds start to decline after two to four years. The longevity of vegetable and herb seeds varies widely, but these basic guidelines will help you judge if your old seeds are worth keeping around.

• Onion, parsley, corn, pepper, and parsnip seeds are relatively short-lived. Their germination rates decline rapidly after one to two years.
• Carrot, bean, pea, and spinach seeds last a little longer, but their germination rates drop after three years.
• Tomato, beet, squash, pumpkin, watermelon, brassica, cucumber, and radish seeds last the longest, and these hardy seeds can stay fresh for four or more years.

These guidelines are only estimates. The life span of your seeds is highly dependent on how you store them.

Factors That Affect Seed Longevity

Germination rates decline as seeds age. Old seeds are often much slower to sprout—if they sprout at all. However, the wrong storage conditions can reduce the viability of seeds and lead to early spoilage. To help your seeds last as long as possible, store them in a spot where they’re not exposed to the following stressors.

High humidity. Damp environments and excess humidity can cause seeds to rot or germinate prematurely. That’s why it’s so important to store seeds in airtight containers and dry locations where humidity levels are low.

High temperatures. Temperatures above 90°F speed up decay and cause seeds to spoil quickly, while cool temperatures keep seeds fresh. Although seeds can be stored at room temperature, they’ll last longer if you keep them in a location where temperatures stay between 32°F and 41°F.

Excess light. Too much light can lead to early spoilage and reduce seed germination rates. If you can’t store seeds in a dark cupboard, put them in opaque storage boxes or jars that keep out the light.

Pests. Rodents and other pests have a taste for seeds. Whenever possible, avoid storing seeds in sheds, garages, and other locations where pests are afoot, and choose rodent-proof seed storage containers made of metal or glass.

How to Store Seeds So They Last

There are just about as many ways to store seeds as there are seeds to store. Here are some basic guidelines to keep in mind if you want your seeds to stay fresh. Whether you’re storing store-bought seeds or seeds collected from your garden, here’s exactly how to store your seeds so they last.

1. Make Sure Seeds Are Completely Dry

It’s essential to ensure your seeds are dry before storing them, as they can quickly rot in sealed containers if they contain even a bit of moisture. Dry seeds should be relatively brittle and break rather than bend when you squeeze them between your fingers. If the seeds still feel moist or you notice condensation in your seed storage containers, spread them on a baking sheet and allow them to air-dry for a few days.

2. Label and Date Seeds

If you’re storing loose seeds, pack them in paper or wax seed envelopes and label them with the seed variety and the packing date. This helps you track the age of the seeds and when you should plant them.

3. Choose the Right Storage Containers

After the seeds are safely tucked away in envelopes or seed packets, store the packets in zip lock bags, mason jars, photo boxes, upcycled takeaway containers, or tins. Ensure the containers are airtight to keep the humidity levels low and rodent-proof if you’re storing seeds in a spot where pests may be active. Placing a few silica gel desiccant packets in the storage containers can reduce humidity issues, too.

4. Organize Seeds as Needed

Some growers may not want to organize their seeds at all, but if you have a lot of seeds, developing an organizational system can be helpful. You can organize seeds in jars by the types of seed or by their planting times, or you can store seeds alphabetically in a photo album, shoebox, or old card catalog. Adding lettered dividers between alphabetized seeds allows you to quickly flip through your collection and find the seeds you want to plant.

5. Store Seeds in the Right Spot

After organizing your seeds the way you like, store them in a cool, dark, dry spot until you’re ready to plant them. A kitchen cabinet or drawer can be a great place for storing seeds, but storing seeds in your fridge or freezer can keep them fresh even longer. Just keep in mind that refrigerators and freezers have relatively high humidity levels, so it’s doubly important to use airtight containers when storing seeds in these cold spots,

How to Use Old Seeds

Even when seeds are past their prime, you may still be able to get some use out of them. Rather than tossing old seeds in the trash, try some of these planting techniques.

• Before throwing old seeds out, test their viability by planting some test seeds in a seed-starting mix and tending them according to the instructions on the seed packets. If some of the seeds sprout, the rest of the seeds may be worth planting.
• Make up for the lower germination rates of old seeds by planting more seeds per planting hole. This increases the chances that at least some of the seeds sprout.
• Try your hand at “chaos gardening” by throwing old seeds in an underused corner of your garden. You never know what may sprout.