Nasturtium, or Tropaeolum majus, is a popular and straightforward plant to cultivate in many gardens. This vigorous grower is entirely edible, offering a unique, peppery flavor profile that comes from compounds called glucosinolates, similar to those found in mustard and horseradish. Maximizing the yield and flavor of this versatile plant requires understanding the specific timing and techniques for gathering each of its distinct parts.
Identifying the Prime Time for Picking
The optimal time to harvest any part of the nasturtium plant is generally in the early morning, just after the dew has evaporated from the foliage. During this period, the plant’s moisture content is highest, which translates to a fresher, crisper texture and a more concentrated flavor profile. Harvesting in the heat of the afternoon, when the plant is water-stressed, can result in wilted material and a less intense taste.
The growth stage significantly affects the flavor of the leaves. For the best culinary quality, focus on picking younger, newly expanded leaves rather than older, tougher foliage. The younger leaves contain the highest concentration of volatile oils, which contribute to the sharp, peppery bite.
Nasturtiums respond well to consistent harvesting, a practice that mimics the effect of pruning. When the plant is routinely trimmed back, it is stimulated to produce more lateral shoots and fresh growth, resulting in a prolonged and abundant yield. This continuous encouragement ensures a steady supply of tender leaves and fresh flower buds throughout the growing season.
Gathering Leaves and Stems
Harvesting the leaves and tender stems requires precision to ensure the plant remains vigorous and continues its production cycle. Use clean, sharp tools, such as small pruning snips or scissors, to make a quick and precise cut, minimizing damage to the remaining plant tissue.
The ideal location for the cut is near the junction where the leaf petiole, or stem, meets the main trailing vine. Taking the entire petiole preserves the structure of the leaf for use as a garnish or in salads. Avoid indiscriminately pulling leaves, as this can damage the main stem and introduce potential entry points for pathogens.
When harvesting, practice moderation, never removing more than one-third of the plant’s total foliage at any given time. Over-harvesting can shock the plant, causing a temporary halt in growth and reducing the overall long-term yield.
The tender stems can also be collected alongside the leaves, offering the same peppery flavor with a slightly crunchier texture. These stems are often used in preparations where a firmer structure is desired, such as finely chopped in pestos or used as a garnish.
Collecting Flowers and Seed Pods
Harvesting Flowers
The brightly colored nasturtium flowers are gathered when they are fully open. To harvest, gently twist the short stem, or pedicel, at its base where it connects to the main vine. This separates the flower cleanly without tearing the surrounding tissue. Flowers should be collected for immediate use as a garnish or for stuffing, as they are highly perishable and their structure quickly degrades after picking. Continuous removal of spent or fully opened flowers signals the plant to invest energy in producing more blooms, prolonging the flowering period.
Harvesting Seed Pods
After the flowers fade, they develop into small, green, ribbed structures known as seed pods. It is crucial to harvest these immature pods while they are still firm, plump, and bright green, before they have begun to dry out or turn yellow. The immature seed pods are often utilized as a substitute for capers, thanks to their pungent, peppery flavor and firm texture. To collect them, snip the tiny stem connecting the pod to the plant. These pods must be processed immediately after harvesting, typically by brining or pickling in vinegar, to preserve their texture and flavor.
Cleaning and Storing the Harvest
All harvested material, including leaves and flowers, should be gently rinsed under cool, running water to remove any dust or small insects.
After rinsing, the material should be gently patted dry with a clean cloth or paper towel. Excess moisture can accelerate spoilage and compromise the crispness of the leaves.
For immediate consumption or use within a few days, leaves and flowers can be stored in the refrigerator. The best method involves placing them loosely in a container lined with a slightly damp paper towel to maintain humidity and keep the tissues fresh.
For longer preservation, leaves can be coarsely chopped and frozen into ice cube trays with olive oil, creating convenient portions for cooking later. The immature green seed pods are not suitable for freezing or simple refrigeration and must be processed immediately into a brine or vinegar solution to create the preserved “nasturtium capers.”