Each year, I try to grow a few different fruits and vegetables. Sometimes the unknown crop turns out to be a dud that produces a lackluster harvest, a pitiful yield, or simply proves to be poorly adapted to my garden. But now and then, we discover a real gem. A plant that thrives in our local climate and soil and tastes delicious. A crop so good, you must grow it again next year.

Instead of pre-ordering the seed packet for next year, you could try to save this year’s seed for free. But will those saved seeds grow a crop identical to the previous year?

Step One: Know Your Vegetable

The first step in seed saving is distinguishing between open-pollinated and hybrid vegetables.

Hybrids are the result of crossing specific parent plants to produce offspring with selected traits such as uniformity, disease resistance, enhanced flavor, and more. However, the offspring of hybrid plants grown in your garden won’t necessarily carry those desirable traits into the next generation. To maintain those traits, hybrid seed production must be highly controlled.

Open-pollinated vegetables, on the other hand, have traits that reliably carry through to the next generation. That’s why many of the unique or experimental plants I grow are open-pollinated. If I like the vegetable or fruit, I can save its seeds and grow them again next year.

The Nuances of Open-Pollination

While open-pollinated crops may seem simple, there are some details to consider. Certain vegetables like tomatoes, peppers, peas, and beans have self-pollinating flowers and need little to no special care for seed saving.

Heirloom vegetables are a type of open-pollinated crop traditionally grown and passed down through generations. They were the backbone of vegetable gardens before hybrids became popular and gardening interest waned. While heirlooms tend to be consistent from generation to generation, there can still be some minor variability even within a single named variety like the ‘Mortgage Lifter’ heirloom tomato.

Other crops, such as sweet corn or cucurbits (squash, cucumbers, pumpkins), are cross-pollinated via separate male and female flowers, which may come from entirely different plants. This makes it difficult to control the genetics of the next generation. If you want to save seeds from cross-pollinated crops, distance is one technique to prevent wind or insect pollination from mixing varieties.

For wind-pollinated crops, the minimum separation distances vary:

• Spinach: 1,300 feet
• Sweet corn: 5,200 feet (in case you were wondering, that’s nearly one mile)

For insect-pollinated crops, the minimum separation distances include:

• Broccoli and onions: 2,600 feet
• Kale and collards: 4,000 to 26,000 feet from certain cole crops
• Melons, radishes, squash, pumpkins: 1,300 feet

These distances are quite large, but they’re how seed companies maintain stable genetics in their seed lines. Of course, they also use other techniques, such as isolation structures and staggered planting times to ensure flowers bloom at different periods.

Seed Saving for Real World Gardeners

While these guidelines might discourage you from saving seeds, you don’t have to be a purist. In my garden, I don’t strictly follow these separation distances, but I still save seeds. After all, if I like the parent plant, maybe I’ll enjoy the offspring too.

Observing plant genetics in action is fun and can lead to delightful surprises, some of which may become staples in your garden.

Good Growing Tip of the Week: Certain crops, such as carrots and beets, are biennial, meaning they need two growing seasons to produce seed. If you plan to collect seed from biennial crops, be sure to account for the extended time that garden space will be occupied.