Nasturtiums are vibrant annuals, known for their attractive round leaves and trumpet-shaped flowers in shades of orange, yellow, and red. Both their foliage and blossoms are edible, offering a distinct peppery flavor. Native to South and Central America, these versatile plants add beauty and a unique taste to any setting.
Growing Nasturtiums Indoors
Growing nasturtiums indoors allows for year-round access to their fresh, edible greens and flowers. They also offer ornamental value, bringing vibrant color to indoor spaces.
Choosing compact or dwarf varieties like ‘Alaska’, ‘Peach Melba’, ‘Whirlybird’, or ‘Vesuvius’ is ideal for indoor cultivation, as they are less sprawling and better suited for limited indoor space. These smaller cultivars maintain a bushy habit and typically reach heights of 12 to 14 inches. Starting seeds indoors offers greater control over germination and early growth.
Caring for Indoor Nasturtiums
Nasturtiums require ample light to thrive indoors, ideally a bright, sunny location like a south-facing windowsill. They benefit from at least six hours of direct sunlight daily. If natural light is insufficient, supplementing with grow lights for about 16 hours a day can ensure healthy growth and flowering. Without enough light, plants may become leggy and produce fewer blooms.
Consistent soil moisture is important; nasturtiums prefer soil that is moist but not waterlogged. Overwatering can lead to root problems, while underwatering stresses the plant. Containers need drainage holes to allow excess water to escape. A well-draining potting mix is suitable; a peat-free multi-purpose mix with added grit or gravel can improve drainage.
Nasturtiums prefer poor soil and do not require heavy fertilization. Excessive nitrogen can promote leafy growth at the expense of flowers. If a boost is desired, apply a diluted balanced liquid fertilizer sparingly when seedlings are three to four weeks old. Maintain indoor temperatures above 55°F (13°C), with an optimal soil temperature for germination around 70-75°F (21-24°C). Avoid placing them near radiators or other heat sources, as high temperatures can stress the plants and affect the taste of edible parts.
Pruning and training help manage the plant’s growth and encourage a bushier habit. Regular trimming of foliage and deadheading spent flowers will promote new growth and extend the blooming period. This maintains the desired size and shape within your indoor environment.
Troubleshooting Indoor Nasturtium Issues
Indoor nasturtiums may face pest infestations. Aphids and spider mites are common pests. Organic methods like insecticidal soap or neem oil are effective for control. Regularly inspecting the undersides of leaves helps catch infestations early.
Leggy growth, characterized by long, stretched stems with sparse foliage, indicates insufficient light. Moving the plant to a brighter location or increasing supplemental grow light exposure resolves this. Pruning back leggy stems can also encourage bushier, more compact growth.
Lack of flowering stems from several factors. Too much nitrogen, often from over-fertilization, leads to abundant foliage but few flowers. Insufficient light is another cause, as nasturtiums need significant sunlight to produce blooms. Ensuring proper light and reducing nitrogen-heavy fertilizers can encourage blooming.
Yellowing leaves may signal overwatering, which can lead to root rot. Ensuring good soil drainage and allowing the top inch of soil to dry out between waterings prevents this. Nutrient deficiencies, less common with a balanced potting mix, could also cause yellowing; a diluted balanced fertilizer may be beneficial.
Harvesting and Enjoying Indoor Nasturtiums
Harvest nasturtium leaves and flowers as needed using scissors to prevent plant damage. Both leaves and vibrant flowers have a distinct peppery, slightly spicy taste, similar to watercress. This unique flavor makes them a versatile ingredient in the kitchen.
Leaves and flowers are excellent additions to salads, adding color and a pungent kick. They also serve as an attractive garnish for dishes, from sandwiches to pasta. Beyond fresh consumption, petals can be frozen into ice cubes or blended into smoothies, offering creative ways to incorporate their flavor and nutritional benefits, including vitamin C.