How can I prevent my marigolds from cross pollinating with other marigolds of different varieties? I want to harvest seeds that will grow and look just like their parents. My yard is really small, so each of my marigolds (they are planted in containers ) are placed just 30 cm away from each other. We also have a few bees that like to visit the garden.
My favorite type of marigolds are the signets. The signet varieties I currently have in my garden are lemon gem, red gem, tangerine gem and lemon star. It would be so frustrating if the seeds I saved will not grow into the same variety as their parent, because I really like these vareities and plan to give them to friends.
I agree that signet marigolds (Tagetes tenuifolia), which have lovely small single (and edible!) flowers are must-haves in the garden!
However, it seems that you are asking the impossible in expecting that the seeds from your plants will yield plants that look exactly the same as this year’s plants. This is primarily because your plants are hybrids, although cross-pollination can further confound the issue.
Here’s why: A critical issue to consider when deciding if it is worthwhile to save seeds is whether your plants are heirloom, open-pollinated plants (i.e., where pollination occurs by wind or insects, not human intervention) or hybrids. The Gem series of marigolds are hybrids, as are most marigolds.
Heirloom seeds are most likely to grow plants that closely resemble the parent plant, although even plants grown from heirloom seeds will differ somewhat from the parent plant, as the seeds are obtained from open pollination and are not clones of one another. Interestingly, plants grown from heirloom seeds are generally not as predictably “alike” as “first generation” hybrids.
Hybrid seeds are developed by cross-breeding 2 different plants, and the plants that grow from these seeds (this is called the “first generation”) are uniform and include traits from each of the parent plants. If you save the seed from a hybrid plant (e.g., one of your Gems), this will grow a “second generation” plant that resembles one of the (original) parent plants, but not the “first generation” plant from which you harvested the seeds. When you plant seeds from a hybrid plant, it is not possible to predict what kind of flowers will result – just be aware that these likely won’t look the same as your current crop. This is part of the fun of gardening, though, so you might still want to try collecting some seeds and see what happens when you plant them next year!
In addition to this uncertainty, consider also that pollen from neighbouring marigolds (not just those in your garden) will likely be carried to yours by the wind and the bees. This will also be a factor in determining what next year’s plants will look like – again, impossible to predict.
The University of Illinois Extension’s Hybrids & Heirlooms provides good information about what to consider when growing plants from seed.
I’m not sure if you usually purchase marigolds as small plants (that’s what I do – I’m lazy) or if you purchase seeds. This year, you may want to purchase the seeds of your favourite signet marigolds and sow them outdoors in your pots, once the danger of frost has passed (it is now March 26). The seeds germinate so quickly that there’s really no advantage in starting the seeds indoors. And you will be guaranteed a crop with identical flowers! At the same, time, you could put aside a few pots for your friends.