What’s the difference between sprouts, cress, microgreens, and baby greens? Learn how to identify different stages of plant growth, and follow a single crop through this growth process – a variety of Kohlrabi called Purple Micro Kohlrabi!
Purple Micro Kohlrabi is a beautiful brassica with a mild kohlrabi flavor. It gets its name from its beautiful purple stems - see below!
Simply put, sprouts are germinated seeds. Sprouting is synonymous with germinating, marking the dawn of a seed’s life and its explosive growth period. During sprouting, the seed coat softens to allow water molecules to pass through its pores. Seeds absorb a lot of water, sometimes enough to triple in size! High water content is the reason sprouts are so crunchy. At this stage of development, the plant lacks chlorophyll, which gives plants their leafy flavor - resulting in a mild, “barely-there” flavor unique to sprouts.
When you eat sprouts on a sandwich or a salad, you can identify the seed by its long, pale, protruding root (usually white or light green). Sprouts are typically harvested, served, and eaten whole.
Kohlrabi Sprouts - Kohlrabi seeds will begin to sprout around day 2. At this point, an embryonic root shoots out of the seed and looks for nutrients and water.
Sprouts have been called "The Riskiest Food in Your Grocery Store" and #1 on food poisoning expert Bill Marler's "Six Foods Bill Marler Never Eats". There have been so many cases every year of people getting sick from consuming sprouts (even a few deaths!) that the FDA even launched a “Sprout Safety Alliance”. So what’s risky to eat and what’s not?
Sprout safety begins with production. Most sprouts at a grocery store or in a bistro sandwich have been intentionally grown in large quantities in optimal sprouting conditions to become sprouts. Mass-produced sprouts are never actually planted; instead, they are packed into cloth bags and repeatedly soaked in water. In high humidity and low light, the seed germinates (sprouts!) faster, but those conditions also allow bacteria to thrive. Close quarters, along with high temperature, high humidity, and low light, are heaven for bacteria, and hell for anyone who has ever felt sick after eating sprouts. Along with bacteria, toxic fungi (mold) can also form easily.
People also most often eat sprouts raw, eliminating any chance for cooking and high heat to kill bacteria. If you’re growing sprouts at home be sure to sanitize the container between batches with a mild bleach solution to kill any lingering microbes that could infect future batches (but more on home growing tomorrow!).
Once a sprout grows its first leaves, it becomes a cress. Those teensy ‘first’ leaves are called cotyledons, and they’re different from a plant’s ‘true’ leaves.
A plant’s true leaves usually look different from its cotyledons (i.e., larger, a different shape, color, and texture), and represent the final leaf shape of the plant. Cotyledons and ‘true’ leaves are analogous to baby and adult teeth. Most plants have two leaf stages, but some varieties such as chervil, cilantro, and parsley have three or more leaf stages. Imagine if human teeth had more than two stages of growth!
Plants with one cotyledon are called ‘monocots,’ and plants with two are called ‘dicots’ – a plant will be one or the other. Cotyledons provide a food reserve to sustain the plant until it can extract energy and nutrition from the sun and the soil (photosynthesis). After the plant begins to photosynthesize, the cotyledons either join the photosynthesizing party or drop away (and no one likes a flake).
Plants shed their cotyledons at varying rates – some only last a few days, others hang around for much longer. Depending on the look you’re going for, microgreens are harvested when they have developed their first set of 'true' leaves.
Kohlrabi Cress – Around day 5-7, roots dig into the soil (or a soil-alternative medium, such as coco husk), and the stem shoots up with two unfurling cotyledon leaves (it’s a dicot!). This stage is what most people think of when they picture “microgreens”—a thin stem with two small (cotyledon) leaves at the top—but it is, in fact, a cress. The first tiny leaves should show up around day 5 and grow until day 7.
Microgreens come after the cress stage. At the point of harvest, microgreens are anywhere from 2-4 weeks old. Despite their young age and small size, microgreens pack quite a punch in the flavor department, tasting surprisingly like their fully mature selves. While sprouts and cress of different plants all look relatively similar to one another, they start to distinguish themselves through looks and flavor at the microgreen stage.
Kohlrabi Microgreens – After a few more days (roughly day 14), the cotyledons fade, and the first set of true leaves emerge from the central stem. Kohlrabi’s true leaves are a green-purple and taste sweet and tangy with a mild-vegetable flavor.
Following the microgreen stage, some plants develop into baby greens. The distinction between micros and baby greens isn’t as clear – but it’s helpful to think of baby greens as older, “overgrown” microgreens with more than one set of true leaves. Baby greens are essentially just smaller versions of the more mature plant -think of baby spinach and spinach, or baby kale and kale; same, but different – baby varieties are just a little smaller and taste a little different.
Kohlrabi Baby Greens – In the following few days (roughly day 21), Micro Kohlrabi will grow taller and develop more sets of true leaves. At this point we have baby greens, or as we sometimes sigh at Farm.One, “overgrown micros.”
Mature Kohlrabi – One to two weeks later (day 28-42), we will have mature kohlrabi greens, and if planted correctly, a vegetable bulb will begin to form. Kohlrabi’s cruciferous vegetable is mildly spicy and most resembles a turnip or cabbage (“kohl” and “rube” literally translate to “cabbage" and "turnip” in German).
Flowering Kohlrabi – Fast forward three months - if left to grow, Kohlrabi begins to flower to produce seeds and self-sow. This is called “bolting,” or the premature production of seeds when a plant “bolts” stems from the center stem. Bolting can be seen in a variety of vegetables, from beet to cilantro to celery. Once a plant begins to bolt, its vegetation will become bitter (sometimes inedible).
Thank you to Dan Bernstein for co-authorship of this article!