What Are Seeds?

Seeds do not have a true expiration date like food, but over time, their viability diminishes. Many seeds can be stored for several years if kept under specific conditions, although their germination rates tend to decrease over time.

Fresh seeds naturally have the highest germination rates, often reaching 90 percent or more for high-quality varieties. These rates decrease with the age of the seed; however, many of the varieties will still germinate into some viable plants after the recommended seeding date.

It also makes sense to test older seeds before sowing to determine if they’re worth using or if new ones need to be purchased. A simple germination test involves taking a sample of the seeds and placing them on moist paper towels to observe how many will sprout within a week or two.

The time of germination of different plant species varies considerably. Fast-germinating seeds such as radishes and lettuce might surface within 3-7 days, but slower-growing types (like carrots or parsley) can take as long as 2-3 weeks. The speed of germination is also influenced by temperature, moisture, and the seed’s freshness.

Seeds are the reproductive part of the plant, containing an embryo and food reserves within them, while the bulb is a modified stem that stores energy for the plant. Seeds need to germinate to become plants, but bulbs are already mature and contain plants within them, waiting to grow when conditions are right.

A good rule of thumb is to plant seeds at a depth of around 2 to 3 times their own diameter. Tiny seeds, such as lettuce or wet flower seeds, need to be covered very lightly or not at all, while big seeds, like bean seeds, can be planted 1-2 inches deep. As always, consult individual seed packets for suggested spacing.

Yes, seeds can be allowed / encouraged to germinate in mediums such as paper towels, rockwool, or a specialty seed starting mix. All you need is moisture, the right temperature, and good oxygen. The soil offers additional benefits, including nutrients and a suitable environment for young plants to grow.

There are various methods to improve difficult germination. 

Pre-soaking: Softens hard seed coats by immersing them in water. 

Scarification: Physically (Mechanical or Scarification) breaks the hard seed shells around the seed in water to penetrate the seed for a consistent moisture and temperature environment for germination. The use of fresh, top-quality seeds also greatly increases success.

You can save seeds from a lot of store-bought vegetables, but how successful you are depends on the vegetable. Organic seeds are much more likely to germinate than commercially grown seeds (non-organically grown seeds), which may have been chemically treated to keep them from sprouting. Hybrid types won’t grow true to type from saved seed.