Easy to grow summer flowering plants from seed suitable for a garden in Geneva

Growing summer flowering plants from seed in a heated glasshouse in Geneva, Switzerland can be a rewarding experience. Here are ten easy-to-grow flowering plants that you can start in a heated conservatory and later transplant into your garden:
- Cosmos: This low-maintenance plant produces daisy-like flowers in shades of white, pink, and red. Sow seeds in early spring and transplant when the risk of frost has passed.
- Marigolds (Tagetes): Marigolds are popular for their bright yellow, orange, and red blooms. Start the seeds indoors 6-8 weeks before the last frost date and transplant them after the risk of frost has passed.
- Sunflowers (Helianthus annuus): Sunflowers come in various sizes and colors, from short, dwarf varieties to towering giants. Sow seeds indoors 4-6 weeks before the last frost date and transplant once the risk of frost has passed.
- Zinnias: Zinnias are drought-tolerant, easy-to-grow flowers that come in various colors and sizes. Start seeds indoors 4-6 weeks before the last frost date and transplant outdoors after the risk of frost has passed.
- Nasturtiums (Tropaeolum): These vibrant, edible flowers are perfect for adding a splash of color to your garden. Sow seeds indoors 4-6 weeks before the last frost and transplant when the risk of frost has passed.
- Calendula (Pot Marigold): Calendula’s bright yellow and orange flowers are also edible. Start seeds indoors 6-8 weeks before the last frost date and transplant outdoors after the risk of frost has passed.
- Sweet Peas (Lathyrus odoratus): These fragrant, climbing flowers can add a touch of romance to your garden. Sow seeds indoors 6-8 weeks before the last frost and transplant outdoors after the risk of frost has passed.
- Snapdragons (Antirrhinum majus): Snapdragons are known for their colorful, tubular flowers. Start seeds indoors 8-10 weeks before the last frost date and transplant after the risk of frost has passed.
- Rudbeckia (Black-eyed Susan): These resilient flowers produce bright yellow, daisy-like blooms with dark centers. Start seeds indoors 6-8 weeks before the last frost date and transplant outdoors after the risk of frost has passed.
- Salvia: Salvia produces spikes of tubular flowers in shades of blue, purple, red, and white. Start seeds indoors 8-10 weeks before the last frost date and transplant outdoors after the risk of frost has passed.
Remember to follow the specific germination, light, and temperature requirements for each plant variety. Once the risk of frost has passed and seedlings have been hardened off, you can transplant them into your garden, ensuring they receive the appropriate amount of sun, water, and nutrients for optimal growth.