Starting nasturtium indoors is a strategic move for gardeners who want an early jump on the growing season. This vibrant annual produces brilliant orange, yellow, and red blossoms that are not only edible but also add a peppery kick to salads. By sowing seeds under controlled conditions, you can ensure sturdy seedlings ready to transplant after the final frost, leading to a more robust and earlier flowering display in the garden.
Benefits of an Early Start
While nasturtium seeds are tough and germination is generally reliable outdoors, initiating the process inside offers significant advantages. An indoor start effectively lengthens the growing period, which is especially valuable in regions with shorter summers. This head start allows the plants to become established and bushier before they ever face the unpredictable weather outside, often resulting in a more abundant harvest of leaves and flowers.
Optimal Timing for Sowing
Timing is critical when learning how to start nasturtium inside. You should begin the process approximately 4 to 6 weeks before your local date of the last expected frost. Nasturtium seeds germinate well in standard seed-starting mix, but remember they prefer slightly warmer soil. Maintaining a consistent temperature between 70°F and 75°F (21°C to 24°C) during this phase will encourage the fastest and most uniform germination.
Container and Soil Preparation
Selecting the right setup is essential for healthy root development. Use seed-starting trays or small pots equipped with drainage holes to prevent waterlogging, which can cause the seeds to rot. The soil medium should be lightweight and well-draining; a high-quality seed-starting mix is ideal. Avoid heavy garden soil, as it can compact indoors and hinder the fragile roots of the young seedlings.
The Sowing Process Explained
To start the seeds, plant them about 1 inch deep into the prepared container. Because nasturtium seeds have a hard seed coat, gently nicking the shell with sandpaper or soaking them in warm water for 12 hours can significantly improve germination rates. After sowing, water the medium thoroughly but gently to settle the soil around the seed, ensuring good contact without displacing it.
Care and Transplanting Guidelines
Once the seedlings emerge, they will require ample light to develop stocky stems rather than becoming leggy. A sunny windows receiving 6 hours of direct sunlight or, preferably, grow lights placed a few inches above the plants will provide the necessary energy. Water the plants when the top inch of soil feels dry, aiming to keep the moisture consistent but never soggy.
Transplanting is all about timing and care. Wait until the seedlings have developed at least two sets of true leaves and the outdoor soil has warmed up. Before moving them outside, harden off the plants by exposing them to increasing amounts of sunlight and wind over a week. When planting in the garden, choose a sunny spot with poor to average soil; overly rich soil can promote lush foliage at the expense of flowers.
