How do you know if a seed is good?

Take the seeds and place them in a container of water. If the seeds sink, they are still viable; if they float, discard them, because they probably won't sprout. First, take a paper towel and moisten it with a spray bottle. Place 10 of the seeds to be tested on the paper towel, and then carefully fold the damp paper towel over the seeds.

Place the paper towel and seeds in a plastic bag, seal it and label the bag with the variety and date. How do you know if your seeds are still viable? Simple, do a seed germination test. Place the seeds in a little water. Those who sink are still viable, those who float are dead.

The flotation test is not reliable. To perform the flotation test, place the seeds in a cup of water to see if they sink or float. The idea is that if they have enough mass to sink, they should be viable. The problem is, with all the millions of different shapes, sizes, weights, and textures of seeds, this test is not reliable.

Some seeds will always float and others will sink regardless of viability. They are small and have so little mass, that even the freshest seeds will float immediately if they fail the test, even when they are viable. So, despite all the recommendations, don't waste time with this test. This is the easiest method.

Simply place the seeds in a cup, jar, or bucket of water and let them soak. Bad seeds will continue to float indefinitely, while good seeds will sink in a few hours. This information can be used to compare the quality of different seeds based on their age and also to estimate the seeding value of a seed package. The purpose of the germination test is to determine if you need to plant some additional seeds to get as many plants as you want, or if you shouldn't bother planting those old seeds.

Place the seeds in rows to help you remember what they are if you're trying different types. This is an example where within a single species, some seeds float and others do not, depending on genetics that have nothing to do with the viability of the seeds. Some seeds germinate best after a period of humid cold that mimics the effects of winter on the seed. Seeds don't last forever, and you don't want to waste time or garden space trying to grow seeds that are no longer viable.

When you have higher viability, it means that more seeds will germinate and you can plant fewer seeds to achieve the desired number of plants in your garden. Seed packs usually indicate the planting year for which the seeds were packaged, as well as the germination rate. If your germination rate is less than 60%, consider buying new seeds or planting them more densely to compensate for the low germination rate. The flotation test works well for large seeds the size of corn, peas, tomatoes, or peppers, but it doesn't work if the seeds are very small, such as carrots or lettuce.

If your germination rate was less than 50%, you can use the heavier planting method above or throw away the seeds. Then, place a second paper towel over the top of the seeds to make sure they are surrounded by moisture. The seeds you received from a friend or from a seed exchange may not have a date, and their germination rate may never have been tested. It's best to mark the seed lines with an ice cream stick or a mark on the side to find out where the seeds are expected to appear.