Q. The marigolds I grew from seed last summer had a combination of height and flower color I liked, so I saved some of their seeds. What can I expect if I plant them? --Ann Nelson, Chicago A: Whether the seeds will grow and what the plants will look like depends on the type of seed you started with and whether they came from hybrid or open-pollinated plants. Plant breeding is complex, but in the most general terms, hybrids are created to combine the best characteristics of two different plants in one plant; while open-pollinated plants are grown to preserve the best characteristics of a single plant over time. The next generation of seeds for each behaves differently. If your marigolds (Tagetes) grew from seeds of a hybrid marigold, the seeds you harvested might be infertile and unable to germinate. Even if they are able to germinate, the plants these seeds produce will have a new set of genes and will look unlike last summer's plants. But if the original marigold seeds were from open-pollinated plants, it's possible the seeds you harvested will produce similar-looking plants. It largely depends on whether this summer's flowers received pollen from the same variety of open-pollinated marigold. If they did, plants will be similar. But, as is often the case, there's a possible twist. Nature relies on bees, other insects or even wind to pollinate plants. If one of these introduced pollen from another kind of marigold, perhaps one that was growing in your neighbor's garden, then your seeds could have a different set of genes that will produce marigolds with different features. The original seed packet will tell you if the seeds you started with were from open-pollinated or hybrid plants. Seed packets always say if they contain F1 hybrid seeds. If this information isn't shown, you can assume the seeds came from open-pollinated plants. If you don't have the packet, the price you paid will suggest which type of seed you bought. Seeds from field-grown, open-pollinated plants are usually much less expensive. Hybrid seeds cost more because they are produced in controlled environments where pollen is often applied by hand. All seed growers must follow procedures that ensure the seeds they produce will grow into the plants that are described on seed packets. The surest way to grow marigolds with the same combination of height and flower color will be to buy fresh seeds for the same marigold variety. But you might get the plants you hope for if last summer you started with seeds of open-pollinated plants and the flowers on the plants they produced were pollinated by pollen from similar plants.
Robin Carlson, Chicago Botanic Garden