What is an Open Pollinated Plant?
Open pollinated plants are plants with seed that has stabilized. This means that when an open pollinated plant cross-pollinates with other plants of the same variety, the seed that is produced as a result of the cross will grow into virtually identical plants like the parent plants. This is considered growing true to seed or true to type. For example, if a "Black Krim" tomato cross-pollinates with another "Black Krim" tomato plant, the seeds from the tomato fruit that results from this pollination will have seeds that will grow into a "Black Krim" plant.
You will often see open pollinated abbreviated as OP, especially on seed packets.
Open pollinated plants may be the original species of a type of plant or they could be hybrids that have become stabilized over the years, like "Kentucky Wonder" beans. Breeders start by crossing two different varieties and then plant the seeds from the resulting hybrid. If they like what the resulting plant is, they will keep on planting successive generations of that first hybrid, selecting the plants that are identical to the one they want to cultivate while discarding any that deviate in any way. They do this over and over, for several generations of seed, until all the seeds collected grow into uniform plants.
Stabilizing hybrids allows breeders to single out and maintain desirable traits, such as disease resistance, flavor, or higher yields.
What does Open Pollinated Mean to the Gardener?
The big advantage of OP plants is that gardeners can save their own seed. If you grow a variety you particularly enjoy or that does exceptionally well in your garden, it is nice to be able to save some seeds and plant the same variety next season.
The more you save the seeds and replant, the better adapted future plants will be to your growing conditions.
Are Open Pollinated Plants Better than Hybrids?
There’s not a lot of difference apparent when you are growing open-pollinated plants rather than hybrids. You can’t tell just by looking at them. There are some instances when hybrid seeds have a growing advantage, such as when they have been bred for disease resistance, heat tolerance, or bigger or more prolific flowers.
There is also a phenomenon called hybrid vigor which is especially pronounced in corn seed. The hybrid varieties tend to have an extra boost of energy that somehow allows them to produce more ears.
Open pollinated plants have a few advantages, too. They tend to be either very flavorful vegetables or beautiful flowers because the only reason they have lasted so many years is that someone chose to save their seed and regrow it. With all the options out there, no one would do that if they didn’t think the plants were terrific.
Open pollinated plants that are grown for more than 50 years are considered heirlooms.
There is also a great deal more variety to choose from in open-pollinated seed. And there are regional varieties that are suited to different growing conditions, while hybrid seed is usually developed to be one size fits all and often is developed for the commercial grower, not the home gardener.
So both types of seed have their pluses. Neither is better. It all depends on what you are looking for.
Only Open Pollinated Seed can be Reliably Saved
As mentioned, one of the biggest advantages of open-pollinated seed is that the home gardener can save seed to grow again next year. This isn’t as easy as it sounds. Saving seed requires more than simply collecting the seed at the end of the season because, as was mentioned above, open-pollinated plants can cross-pollinate with other dissimilar varieties and produce seed that is no longer the open pollinated variety.
To become adept at saving seed you have to read up on which plants will cross-pollinate with what other plants and how far the pollen will travel. Then you can grow them at a sufficient distance from one another so that the pollen of one never reaches the pollen of another. Another option is to choose plants that bloom at different times, so they aren’t pollinating at the same time. Seed saving is a fascinating topic that is too large to be covered here, other than to say that only open pollinated seed will grow true to type.