MICRO GREENS & BABY LEAF

Microgreens: larger than a sprout, smaller than a baby salad leaf - they're the latest trend to hit the gourmet food world and a diverse crop growers are beginning to embrace.

Microgreens have actually been in production for a few years now, although variety in the past was limited to largely fresh wheat grass for juicing, snow pea shoots and a few other garnishes. Microgreens originated in California where innovative chefs started using them to incorporate colour, flavor and texture into their dishes - a trend which rapidly spread across the U.S. Now microgreens are being produced commercially in many countries and the diversity of production methods and species grown is ever increasing. Microgreens have many of the health benefits of sprouts, most pack a powerful punch of flavor for their tiny size, and these delicate mini plants are springing up on trendy restaurant menus at an explosive rate. Microgreens appear as toppings, garnishes and flavourings in salads and feature in many up-market dishes as well as being sold in produce stores and supermarkets.

What makes microgreens & baby leaf so unique is perhaps the diversity of crop species being produced and the fact that they are incredibly well-suited. Microgreen & baby leaf plants grow in soilless media with high cleanliness and hygiene requirements.

DEFINING MICROGREENS & BABY LEAF

It can be rather hard to define at exactly what stage of growth a particular crop species would be called a microgreen or baby leaf. Generally, microgreens are larger than a sprout and have produced at least two true leaves after expansion of the seedling leaves or cotyledons. However some growers harvest them at the seedling leaf stage while others let their microgreens develop and produce up to four true leaves. Many even grow their crop to the specifications of their market, allowing chefs to decide how many leaves they want on their microgreen product at harvest. Many species are simply grown to a predetermined height – often 2 to 3 inches before harvesting. Microgeen seed is grown at a high density so that the developing seedlings grow tall and straight with a tender almost blanched stem and bright, well-developed leaves.

Baby leaf is grown 6 to 8 inches and then harvested.

HEALTH-GIVING PROPERTIES OF MICROGREENS & BABY LEAF

Some species are grown specifically for their healthy compounds and properties and these have found a niche market within the health food industry. The most well known of these is wheatgrass, which has been grown for many years as a fresh or frozen health supplement after juicing. Wheatgrass is considered a highly nutritious and cleansing food source rich in vitamins, minerals, amino acids, antioxidants and enzymes. Other species such as flax, chia, broccoli and varieties of red brassica also have health compounds. The darkly colored purple/red varieties of radish which produce intensely-coloured young leaves contain high levels of antioxidants linked to having anti-cancer properties.

SHOOTS AND TENDRILS

Pea shoots have been in use as a gourmet salad item or garnish longer than most other microgreens, however their popularity continues to grow and other `shoots' such as sunflowers are now also making an appearance. Pea shoots have a tender flavor similar to young snow pea pods and a long, white, succulent yet crunchy stem which adds both texture and flavor to many dishes. In the past the snow pea has been grown for shoot production, however there are new varieties have been developed for the production of pea tendrils. Pea tendrils are the part that the plant uses to attach onto supports; they are long, thin, feathery and decorative which makes them popular as a garnish. Varieties of peas which produce less leaf and more attractive tendrils have been bred and yield a higher weight of harvested product and will even regrow if not cut too low at harvest. Corn shoots are another microgreen harvested at the 2 – 3 inch stage these taste like mild fresh sweet corn.

FLAVORFUL GREENS

Some of the flavorful microgreens may come as a surprise to both hydroponic producers and customers. Many commonly available vegetables now have a mini microgreen version which has the same flavor but can be used in more diverse ways

SPICY GREENS

Some greens are grown for their attractive appearance, texture or color, while others are highly sort after for their flavor and aroma. Many of the microherbs are grown specifically for their distinctive flavor which is often more subtle and delicate than the mature plant. Other `spicy or pungent' greens may be used in combination with the lesser flavoured types in salad mixes or used on their own as an important constituent of a dish.

TENDER GREENS

While lettuce varieties often make up the bulk of mesclun or baby leaf salad mixes, the tender or succulent species used for microgreen production are quite diverse and includes a range of leaf sizes, shapes, colours and textures.

ARUGULA

Arugula is one of the most popular microgreens due to its distinctive tangy, nutty almost astringent flavor which is well developed in even tiny seedlings.

BASIL

Both green varieties of basil such as Genovese and red types such as Dark Opal are another widely grown microherb. Some lesser known types of basil such as lemon, Thai and cinnamon basil are also grown as microgreens for specialised markets. Basil microgreens are also highly attractive and have a subtle flavor and aroma which is not overpowering in salad mixes. Basil germinates and grows rapidly in microgreen systems; however it has a higher heat requirement than many of the traditional greens and heating is usually required for winter production.

RADISH

Radish microgreens have a surprising flavor and some varieties are as hot and pungent as a fully mature radish root. There is a lot of diversity amongst the radish varieties used for microgreen production: colours include green pinkish red and vivid purple and this is one of the easiest greens to grow. Radish is used as a color spiker or garnish and the darker coloured types are high in vitamins, minerals and antioxidants.

CHIVES

Baby chive leaves are highly decorative and often used to replace mature chopped chive leaves. Chives are slower to germinate than many other microgreens and production times are longer. They can be sown at a very high density and the clumps harvested by cutting at the base when they reach the required height.

BROCCOLI

Broccoli microgreens are rich in the compound sulforaphane, considered to have many health benefits due to its anti-cancer and anti-bacterial agents.

WATERCRESS

Watercress is a less common microgreen possibly because of its slow rate of growth from seed. Watercress has a peppery flavor and makes an attractive, bright green garnish. It also has proven health properties and contains good amounts of vitamin A, C, calcium ion and folate as well as isothiocyanates which are cancer-fighting compounds. Watercress grows extremely well in NFT and solution culture hydroponic systems and has considerable potential as a microgreen crop.

PARSLEY

Flat leaved parsley is one of the most popular microherbs and can be grown at a high density and harvested at the one or two true leaf stage depending on customer requirements. Its flavor is mild but distinctive and it contains none of the fibrous stems that older mature parsley can develop.

CILANTRO

Cilantro microgreens are one of the most popular miniherbs and can develop a reasonably strong flavor under warm growing conditions. Cilantro is a warm season crop and needs at least 22to 26 degrees C for germination - conditions similar to what's required by basil minigreens, making them ideal to be cropped together where heating is required.

FRENCH SORREL

Sorrell has a very distinctive, sharp, acidic and slightly-bitter flavor and can be used as a salad spiker. Often mature sorrel becomes too intense or acidic, however the microgreen version is milder and less bitter, although can be slow growing and prefers cooler growing conditions.

MINT

Mint is a lesser grown miniherb, possibly because mint seed is tiny and slow to develop into a small plant. The flavor is mild, yet distinctive and the micro plants are highly attractive. Mint prefers cool growing conditions and performs well in NFT and other hydroponic systems where plenty of moisture is provided. Mint microgreens need to grown under shade in summer with the nutrient solution temperature monitored and chilled to prevent it from becoming too warm for good mint germination and production.

DILL

Dill microgreens have become popular in fish dishes, often replacing mature chopped dill. The flavor is very mild, but the foliage is similar to fennel in appearance - feathery and attractive, although very lightweight.

SHISHO

Red/purple and green shisho (perilla) - sometimes referred to as the Sushi herb used in Japanese cuisine - has become more popular as a salad green. Perilla is an attractive and well-flavored microgreen with leaves resembling an ornamental coleus. It's a challenging microgreen to grow because the seed needs to be relatively fresh to germinate well and also benefits from stratification at 5 degrees C under moist conditions before sowing. Perilla seed also needs light to germinate and should be lightly sown into the top of the growing media or mats.

SPINACH

English spinach has a dark green leaf and very mild flavor. Spinach seed can have a low germination rate, particularly if conditions become overly warm. Optimum temperatures for germination are 16 to 22 degrees C. Under high temperatures, a large proportion of the seed may fail to germinate and this can then rot in the microgreen system and cause disease. Spinach is a cool season crop which benefits from summer shading and nutrient solution chilling.

BEET

Beet types such as Bulls Blood is primarily grown for its intense red color on even very young seedlings.

TATSOI

Tatsoi has a rounded leaf and thick white petioles with a crisp texture and has a rapid germination and growth rate. This is a highly productive microgreen for hydroponic systems and has few problems.

MITZUNA

Mizuna has an attractive light green serrated leaf and is one of the fastest and most productive microgreens to grow. Germination is rapid and the crop usually has few disease problems. Mitzuna has a very mild mustard flavor and a wide range of uses.

AMARANTH

Red amaranth is grown primarily for its deep color and attractive leaves, although green types with pink stems also exist.

CHARD

Chard is available in a range of colors including yellow, pink, red and green and it has a mild spinach taste. Seed germinates readily although Chard is more of a cooler season crop with a slower growth rate than lettuce.

KALE

Microgreen kale produces succulent and tender leaves which are finely cut and almost blue-green in color. Another cooler season green, its color becomes paler under warm growing conditions.

MACHE

Also called corn salad or lamb's lettuce, mache produces rounded leaves with a lettuce-like growth. It's a common ingredient in baby leaf mixes and its microgreen version has many uses and can be harvested from the two to four leaf stage.

LETTUCE

Lettuce microgreens are relatively easy to produce in most systems, however germination problems can occur once temperatures reach 26 degrees C or higher with seed going into secondary dormancy. Shading and chilling may be necessary in hot summer climates for high quality microgreen production of lettuce.