Feasting on flowers has a long culinary history. In the Victorian area, edible flowers were particularly popular and used to create elegant designs of candied violet and borage to top cakes and desserts. In more recent times, edible flowers are recognized not only for their beauty and decorative value, but also for flavor, aroma, and nutritional aspects. Edible flowers are incredibly versatile; they are brewed as tea, used as a spice or vegetable, dried, candied, incorporated into baking, or simply scattered fresh as a garnish. They are grown commercially by hydroponic producers for restaurants, candymakers, tea blenders, produce stores, salad mix producers, and bars, where modern mixologists incorporate edible flowers and floral infusions into drinks.
Within the range of edible flowers, some are merely colorful additions to brighten up salads or as garnishes, while others pack a real flavor punch, creating a gourmet experience of even the simplest dishes. Many strongly flavored herbs produce flowers with a similar flavor and aroma to the foliage, while others are completely surprising and provide added interest to taste profiles.
Cultivation, Harvesting, and Storage of Edible Flowers
However, as mentioned, edible flowers are more than colorful petals. Many common hydroponic crops, include broccoli, cauliflower, and artichoke, are the floral tissue of the plant. The spice saffron derives from the stamen of the crocus flower and capers are the picked flower buds of the caper bush. Some plants may be grown specifically to produce edible flowers, while others service a dual purpose of providing fresh fruit, vegetables, or herbs as well as a crop of flowers for consumption or garnishes. Smaller hydroponic growers often don’t intentionally focus directly on edible flower production; instead, they simply allow a few plants to flower at the end of their life cycle for a harvest of blooms.
Hydroponics and indoor gardening offers some distinctive advantages when it comes to producing edible flowers. Since the fresh blooms are very fragile, washing them after harvest is often not an option. So, a growing environment that is clean, dust free, has no contact with manures or pesticides, and protects the delicate petals from outdoor elements produces the highest-quality edible product.
Choosing which hydroponic system to use for edible flowers is largely dependent on the species being grown. Many of the most commonly used edible flowers produced in hydroponics are herbs and salad greens, which can easily be grown in nutrient flow technique (NFT) and other solution-culture systems. Small, compact annuals are also well-suited for NFT, or they can be grown in substrate-based systems. Larger plants such as broccoli, squash, artichoke, elderberry, and lavender are more suited to substrate-filled containers or beds with drip irrigation due to the extensive nature of their root system.
Edible Flower Harvesting and Storage
Edible flowers should be harvested early in the day and only those that are half open or recently fully opened (species dependent) should be selected. Harvested flowers should be then placed immediately into cool conditions, inside a plastic bag, and under refrigeration to prevent excessive moisture loss. Flowers with long stems can be placed into a jar of water and kept in a cool place until used. Most edible flowers have the petals removed before use and for some, such as marigolds and roses, the bitter white base of the petal should be removed. Edible flowers may be used fresh in salads, salad dressings, and vegetable dishes; cooked in stir-fry dishes; stuffed and fried or baked; incorporated into baked goods; added to herbal butters; made into pancakes; candied with sugar; or preserved into jams, jellies, dried mixes, pickles, wines, or drink syrups.
Types of Edible Flowers
Correct identification of the flower species is important as not all blooms are edible. As such, only harvesting edible flowers from those cultivated as an edible crop is always a good idea.
Garlic chive flowers and the pink blossoms of the chive plants are often used as both a flavorings and garnishes. They have a distinctive onion flavor that can be relatively strong. If a grower wishes to harvest both chive foliage and flowers, then a compromise needs to be reached in terms of production. Often, groups of chive plants are set aside for flower harvest. Temperatures greater than 81˚F with a long day length promote the formation of flower stalks, which also restricts foliage development. On the plants used for foliage, those tough, fibrous flower stalks are totally removed.
Coriander, or cilantro, is another herb with edible flowers. The white blooms are milder in flavor than the foliage. However, the flowers should be harvested before seed begins to set, which can occur rapidly under warm growing conditions.
The white or pale pink flowers of a basil plant have a mild, spicy flavor, while chervil and fennel flowers have a faint anise flavor. Mint flowers often taste mildly of mint; however, this is quite variable between the different species of mint, so taste testing the flowers before harvest is recommended to avoid overly strong blooms. The flowers of woodier herbs such as thyme, sage, oregano, and rosemary all have flavors and aromas like the foliage, though often they are a milder herbal taste. Arugula flowers, a popular addition to salad mixes, are small and white with a spicy flavor that can become strong under certain growing conditions. Borage flowers have long been used as a garnish and edible bloom due to their attractive blue color and size. They have a mild cucumber-like flavor and are not overpowering in salads and drinks.
Summer Squash Flowers
Summer squash, also known as zucchini or courgette, provides two marketable products: fruit and the large edible flowers. The latter are often prepared as a delicate dish by stuffing, coating, and frying. Italian varieties such as Costata Romanesco are excellent producers of high-quality flowers, which are harvested at an early stage. However, all zucchini flowers are edible. Flowers and fruit with flowers attached are specialty crops. As such, they often receive premium prices compared to zucchini fruit alone to compensate for the lower yield and greater investment in labor and handling practices.
With squash plants, it is important to be able to distinguish between the male and female flowers. Male flowers form on a long, thin stalk, usually lower down on the plant. These are harvested for edible flower production. The female flowers, on the other hand, produce a small fruitlet, which later develops into the harvestable courgette fruit. By only harvesting the male flowers just as they open and leaving the female flowers to form fruit, courgette plants can provide two products from the same crop.
Courgette flowers have a short shelf life, thus they need to be harvested daily at the correct stages of maturity. They also need to be handled with care. The male flower stalks should be cut two to three inches down from the bud before the flower begins to fully open. For those growing edible squash blooms for market, the harvested blossoms should then be packed in rows on trays on shallow boxes and chilled immediately to slow the rate of flower opening and preserve the delicate tissue. Ideally, these should be prepared and eaten within a few hours of harvest. A market also exists for very small courgette fruit with the female flower still attached. Fruit needs to be harvested before the flower fades, typically at around two to three inches. Timing is critical for this process.
Since the shelf life of zucchini flowers is short, hydroponic growers with a local market have a real advantage in terms of getting a super-fresh, high-quality product to the customer. The production of squash plants for edible flower production is much the same as for those grown for fruit harvests, though the plants require a little more space to ensure the blooms have sufficient room to develop and to make harvesting easier. Maintaining good air flow around the base of the plants is also essential as the flowers can be prone to developing fungal rots when humidity is high and if an overly dense canopy of leaves develops. Media-based hydroponic systems are preferred for squash flower production as the plants have a large root system at maturity. Stone wool or coco fiber slabs, media bags, Dutch buckets with perlite, and similar substrates all work well for these flower crops.
Other Edible Flowers
Calendula and marigold are fast-growing annual plants, well-suited to hydroponics and perhaps some of the most widely recognized edible flowers. Their petals have a slightly bitter and peppery flavor and a bright orange-yellow color.
Elderberry is a small shrub that produces a large inflorescence of tiny white blooms with a sweet floral fragrance and flavor. These flowers are traditionally used to make cordials and syrups, but can be cooked and used to make desserts and preserves.
Lavender flowers have an intense, perfumed flavor that can be overwhelming if used in excess. The flowers can be used in salads, but they are more commonly used in sweet dishes and baking.
Nasturtium is an edible flower with a long history of use, particularly in salad mixes. The seed pods, which form after the flower has faded, can also be pickled and used as a caper substitute. Nasturtium flowers come in a range of yellow, orange, and red shades and have a spicy, peppery flavor that can become strong on older plants. Nasturtiums are a flowering annual that is easy to grow from seed. There are also new, more compact bedding plant varieties available for those with limited growing space.
Pansies, violas, and violets are other edible flowers well-suited to small growing spaces and thrive in NFT systems. These flowers have a mild, slightly sweet flavor and are often candied with sugar and used for cake decorating. Violets are sweetly perfumed and used for scent as much as for flavor.
Rose petals have a long culinary history in desserts, preserves, and syrups. The perfumed flavor, however, varies considerably between species and with different growing conditions.
Beside the green vegetable, garden peas also produce edible shoots, tendrils, and flowers with a mild pea-like flavor that can be used as garnishes and additions to fresh salads. Sunflowers are a multi-purpose edible flower. The large buds may be harvested before they open. Steamed, these are said to have an artichoke-like flavor. The open petals have a sweeter, yet slightly bitter taste.
With the increasing trend of seeking out new tastes, textures, and nutritional foods, edible flowers have grown in popularity and are now an established niche market for hydroponic growers. Tasting and trialing different edible flower flavors and textures are a great way to experiment with these diverse and innovative crops. While edible flowers are often very fragile, require careful handling during harvest, and highly perishable, they are a great addition to a hydroponic system that facilitates direct garden-to-table movement.