Introduction

Microgreens, also known as microgreens, are young seedlings of vegetables, herbs, or grains harvested just a few days after germination. They are characterized by their tiny size, concentrated flavors, and rich nutrients. Increasingly popular in vegetarian cuisine and haute cuisine circles, they are both easy to grow and very versatile in the kitchen.

In this article, we will discover how to produce microgreens using a simple empty jam jar. This method is practical for those who lack space or do not want to invest in sophisticated gardening equipment. You will see that with a few tips and a little attention, you can enjoy homemade microgreens all year round.

What are microgreens?

Microgreens are the very first stage of plant growth, before reaching the stage of a young shoot or more developed seedling. Harvesting usually takes place after the appearance of cotyledons (the first “false” leaves) and sometimes just as the first true leaf begins to form.

The most common varieties of microgreens include:

• Leafy vegetables (kale, mustard, spinach, lettuce, etc.)
• Aromatic herbs (basil, coriander, parsley, etc.)
• Legumes (peas, lentils, mung beans, etc.)
• Grains (wheat, oats, barley, etc.)

Their reputation is growing due to their high nutritional value. Indeed, microgreens contain concentrated amounts of vitamins, minerals, and health-beneficial compounds. They hold a special place in vegetarian and vegan cuisine, as they allow for varied nutritional intake and enhance the flavor of many dishes.

Why grow microgreens in a jam jar?

The jam jar, usually made of glass, offers several advantages for growing microgreens:

1. Recycling and reuse
   Growing microgreens in a jam jar is an excellent way to reuse a container that is no longer needed. Instead of throwing it away, it is given a second life. This is a small gesture in favor of the environment.

2. Practicality and space-saving
   Jam jars are compact and easy to place on a windowsill, a kitchen corner, or any space with minimal natural light. For people living in apartments or without a garden, this solution is ideal.

3. Moisture retention
   The glass allows you to see the moisture level of the substrate and control germination. Additionally, thanks to the shape and vertical walls of the jar, moisture is relatively well retained inside, promoting the initial growth of seedlings.

4. Light management
   Although most microgreens like to receive light, some types of seeds need a short period in the dark (germination phase) before enjoying more intense light exposure. Jam jars can easily be covered with a cloth or placed out of light at the beginning of cultivation.

Necessary materials

To grow microgreens in a jam jar, you will need:

• A clean jam jar: Any size can work, but a jar of about 250 to 400 ml is sufficient in most cases. Make sure it is well cleaned and free of any food residue.
• Suitable seeds: It is best to obtain seeds certified for microgreens production or untreated vegetable seeds. Radish, cress, mustard, sunflower, pea, and lentil seeds are excellent choices to start with.
• Substrate: You can use special seedling soil, coconut fiber, or even an alternative support like paper towels (although the yield may be lower). Seedling soil is the easiest to manage and provides good results.
• A saucer or bowl: To drain excess water or keep the jar slightly tilted, facilitating the removal of excess moisture during the germination or watering phase.
• A spray bottle or a watering can with a fine spout: To water the seeds and young shoots without disturbing them.

Seed selection and precautions

Before you start, make sure to choose seeds suitable for microgreens cultivation. Some seeds sold commercially are chemically treated to facilitate storage or prevent diseases, and they are not recommended for consumption as microgreens. Ideally, look for seeds from organic farming or labeled “special germination.”

Regarding quantities, know that microgreens are sown quite densely. A standard jam jar (about 300 ml) can hold the equivalent of one to two tablespoons of seeds, depending on their size. Radishes, for example, are relatively large compared to cress seeds, so adjust the quantity accordingly.

Furthermore, check for any allergies. Although rare, some people may be allergic to certain legumes or seeds. Be attentive to your sensitivities or those of your surroundings.

Cultivation steps

1. Preparing the jar

• Thoroughly clean the jam jar with hot water and soap, then rinse and let it air dry. It is important to start with a clean container to reduce the risk of mold or contamination.
• If you prefer, you can disinfect the jar by filling it with boiling water or soaking it in a lightly bleached solution (then rinse well).

2. Pre-soaking seeds (optional depending on varieties)

Some seeds, particularly larger ones like sunflower, pea, or bean seeds, benefit from a few hours of pre-soaking to facilitate germination. If you use radish or cress seeds, this step may be less necessary, as their seeds germinate quickly.

• Place the seeds in a glass of water and let them soak for 4 to 8 hours (or even 12 hours for some varieties).
• Then gently drain them using a strainer.

3. Placing the substrate

• Place a layer of substrate at the bottom of the jam jar. You can fill the jar up to about a third or half of its height to leave room for the roots.
• Lightly pack the substrate so that it is firm enough, but without compressing it excessively. A too compact substrate could suffocate the seeds.

4. Sowing the seeds

• Spread your seeds evenly on the surface of the substrate. You can sow them quite densely, but make sure they are not overlapped too thickly. The goal is to obtain a homogeneous carpet of young shoots later.
• If you wish, cover very lightly (a few millimeters) with a thin layer of substrate, especially if the seeds are quite large. For radish, cress, or other small to medium-sized varieties, it may be enough to leave them on the surface but ensure good moisture is maintained.

5. Watering and first day in the dark

• Using a spray bottle or a watering can with a fine spout, moisten the surface of the substrate. The goal is to maintain moisture without completely soaking.
• Optionally cover the jar with a cloth or perforated plastic wrap to prevent rapid evaporation and retain the necessary moisture for the seeds.
• Place the jar in a slightly heated place (ideally 20 to 25°C) and out of light for the first 24 to 48 hours, according to the specific recommendations for your seed variety.

6. Gradual exposure to light

• As soon as the seeds begin to germinate and small white radicles appear, you can remove the cover and expose the jar to light. Microgreens need moderate to strong light to perform photosynthesis and develop their beautiful green color (or slightly purple depending on the varieties, like purple basil).
• Ideally, place the jar near a sunny window, but avoid too intense direct light in midsummer, which could quickly dry out the support or damage the young shoots.

7. Daily maintenance

• Spray or lightly water once or twice a day, depending on the ambient humidity level. The substrate should remain moist, but not soaked.
• Ensure that water does not stagnate at the bottom of the jar. If necessary, gently tilt the jar to drain excess water.

8. Harvest

• Depending on the chosen seed variety, you can harvest your microgreens about 7 to 14 days after sowing.
• Radishes, for example, can be harvested in just a week, while peas require a little more time.
• To harvest, use small kitchen scissors and cut the shoots just above the substrate. You can also pick a portion and let the other continue to grow, but in general, microgreens do not really regrow after cutting; you will need to start a new sowing to renew production.

Managing common problems

1. Mold and fungi

In a confined and humid environment, white mold may appear. They may simply be radicles of seedlings, which give the impression of a fuzz on the surface. Make sure to distinguish these radicles (harmless) from real mold. If a true fungus settles, you will recognize it by its unpleasant odor or suspicious color (green, gray, black). To avoid this problem:

• Regularly ventilate by removing the cover
• Avoid overwatering
• Disinfect your jars and use clean substrate

2. Seeds not germinating

Several factors may be involved:

• Seeds that are too old or bad
• Lack or excess of water
• Temperatures too low or too high Ensure you respect ideal growing conditions, use quality seeds, and check the substrate’s moisture.

3. Excessive elongation of shoots

Etiolation occurs when seedlings are very thin and elongated, often pale green. This usually happens when shoots lack light. To avoid this phenomenon, provide them with brighter light and move the jar closer to a sunny window or an appropriate lamp.

What types of seeds to grow in a jam jar?

Although a wide variety of seeds can be grown, some are particularly well-suited:

1. Radish
   Radish microgreens are famous for their spicy taste and ultra-fast growth. In just 5 to 7 days, you will have vibrant and delicious shoots.

2. Cress
   Cress is also very easy to germinate, requires little substrate thickness, and offers a lively flavor reminiscent of mustard.

3. Mustard
   Mustard seeds grow quickly, and their microgreens have a pronounced, slightly spicy taste. They are somewhat similar to radish microgreens.

4. Sunflower
   Sunflower microgreens, more fleshy, require a little more space and pre-soaking. They offer a mild flavor and a crunchy texture.

5. Peas
   Pea shoots, tender and sweet, are often called “pea shoots” in English cuisine. They are very suitable for salads or stir-fries.

6. Basil
   Basil can be slower to germinate and grow, but its microgreens are very fragrant and ideal for enhancing tomato sauces, salads, and Italian dishes.

7. Fenugreek
   Generally appreciated for its slightly bitter and spicy flavor, fenugreek is easy to grow, especially if pre-soaked.

Incorporating microgreens into your diet

Once your microgreens are harvested, several options are available to incorporate them into your dishes:

• Salads and raw vegetables: Microgreens (radish, cress, mustard) enhance the taste of your mixed salads. Their crunch and freshness are very appreciated.
• Sandwiches: Add a handful of radish or pea shoots to your sandwiches or paninis for a light texture and subtle flavor.
• Soup and veloutés: Sprinkle your microgreens on a vegetable velouté or soup. They will bring a touch of color and an interesting flavor dimension.
• Spreads: Mix some microgreens with mashed avocado or a plant-based cream cheese, then spread it on whole-grain bread or toasts.
• Pizzas and pasta: Finally, sprinkle basil or mustard microgreens on a freshly baked pizza, or integrate them at the last moment into your pasta dishes for a concentrated flavor and a nice presentation.

What is the nutritional value of microgreens?

Microgreens generally contain a higher concentration of nutrients than the adult plant. Studies have shown that they are particularly rich in:

• Vitamins (A, C, E, K, and some B vitamins)
• Minerals (calcium, iron, zinc, magnesium, potassium)
• Antioxidants (polyphenols, carotenoids)
• Dietary fiber (in smaller quantities than the adult plant, but still present)

However, it should be noted that there are variations depending on the varieties. For example, red cabbage and broccoli microgreens can be particularly rich in anthocyanins (for red cabbage) or sulforaphane (for broccoli). In general, their interesting nutritional profile has made them a star of healthy nutrition and an excellent alternative to vary sources of vitamins and minerals.

Tips for successful and creative cultivation

• Alternate varieties: To avoid routine, try growing several varieties at the same time or in rotation (for example, radish and cress, then peas and sunflower).
• Be patient: Each seed has its own growth rhythm. Radish shoots appear faster than basil or sunflower.
• Layering: If you have several jars, you can stack your containers on a small stand. This saves space and plays with the aesthetics of your plants.
• Personalize your jars: For more conviviality, decorate your jam jars with labels, stickers, or colored ribbons. Not only does this add a touch of cheerfulness to your kitchen, but it will also allow you to quickly identify the cultivated variety.
• Monitor temperature: Microgreens appreciate a mild temperature between 18°C and 25°C. Avoid cold drafts and too hot areas (near a radiator, for example).
• Try rotation: For continuous production, sow a new jar each week. This way, you will have a regular harvest of fresh microgreens.

After the harvest: what to do with the substrate and the jar?

• The substrate: Since microgreens are harvested very early, the substrate will have consumed a modest amount of nutrients. You can reuse this soil for flower seedlings or compost it. If you notice potentially problematic mold, it is best to discard the substrate or sterilize it before composting.
• The jar: Simply clean your jam jar again with hot water and soap, or even put it in the dishwasher if possible (check that it can withstand the temperature). You can then start a new production cycle or use it to store food.

Conclusion

Growing microgreens in a jam jar is a rewarding activity accessible to everyone, even complete beginners in gardening. Space-saving, economical, and ecological, this method will allow you to enjoy young shoots rich in flavors and nutrients all year round. From preparing the jar to harvesting, each step is an opportunity to reconnect with life and witness the incredible power of germination.

Whether you are vegetarian, vegan, or simply curious to discover a new source of fresh food, microgreens can quickly become a major asset in your kitchen. They lend themselves to almost any recipe and allow for the exploration of multiple flavors. So why not grab one of your jam jars and give it a try? You will be amazed at how simple and fun it is to grow little plant wonders at home. Happy sowing and enjoy!