Must-Know Tricks to Grow Microgreens Indoors During Winter with Grow Lights

There are many varieties of microgreens, from peas and sunflowers to radish and broccoli. These popular choices share similar growing habits but offer distinct flavors and textures, giving gardeners the joy of discovering personal favorites.

One of the biggest advantages of growing microgreens is that they can thrive indoors year-round under grow lights, without taking up much space. While the process may seem simple, there’s an art to getting it just right.

This blog will cover practical tips and tricks to make growing microgreens smoother and more successful, especially helpful for those embarking on this new adventure. Growing indoors is a great way to stay connected to the garden through every season, enjoying quick growth, rich nutrients, and fresh flavor, all with a setup that fits easily anywhere in the home.

Many gardeners even grow microgreens under lights during mild seasons, when natural sunlight is plentiful. There are good reasons for that, and this blog will explain why. Let’s get to it.

 

1. Sunlight is important, but consistency matters more.

Even when natural sunlight is limited, artificial lights or fluorescent lights can provide an adequate light source to maintain steady plant growth. With the right light system, organic seeds, and a simple setup using coconut coir or peat moss, home gardeners can grow healthy microgreens full of flavor and high nutritional value throughout the winter months.

2. Skip the garage and choose a controlled location.

Sprouting microgreen seeds in a garage might seem convenient, but if the space lacks temperature control, growth will quickly stall. A controlled environment means the right light intensity, color temperature, and balanced moisture levels. 

3. Choose fast-growing microgreens that are more forgiving.

Radish, mustard, arugula, and broccoli microgreens germinate quickly and tolerate moderate indoor light conditions. These varieties maintain steady growth under artificial lights and adapt easily to limited natural light, making them dependable choices during the winter months.

4. Consider slower-growing microgreens for a challenge.

Basil, cilantro, and beet microgreens need longer light exposure, slightly warmer temperatures, and consistent moisture to develop evenly. These crops respond best to a stable indoor environment with balanced light intensity and warmth, rewarding the effort with rich color, strong aroma, and concentrated flavor once mature.

5. Set up full-spectrum LED grow lights 4–6 inches above trays.

Light placement needs to be at a sweet spot, close enough to provide full, even coverage but not so near that seedlings dry out or scorch. Maintaining this balance supports steady growth and prevents stress on tender stems and leaves.

6. Choose the right light for the plants.

Full-spectrum LEDs that mimic natural daylight (around 6,500K) encourage strong stems, deep green color, and compact growth. As seedlings develop, the light height should be adjusted to keep intensity consistent and prevent leggy or pale sprouts caused by uneven exposure.

7. Consider grow planters with built-in light systems.

While it’s possible to install and adjust grow lights manually, many grow planters now come with integrated lighting designed to deliver the correct light spectrum and intensity. These setups eliminate much of the trial and error, providing a reliable environment that’s ready to use and easy to maintain indoors.

8. Maintain 12–16 hours of light daily for balanced growth.

Microgreens depend on steady light cycles rather than intense bursts of sunlight. A simple timer helps keep lighting consistent and prevents overexposure, especially convenient if it includes a self-activating feature. 

9. Microgreens speak louder than words.

Growth patterns often reveal exactly what’s needed. Pale or elongated stems suggest insufficient light exposure and may need slightly longer lighting periods. On the other hand, curled leaves or dry edges indicate too much light or heat. 

10. Keep the temperature between 65–75°F (18–24°C).

Warmth supports steady germination and prevents fungal issues that thrive in cooler, damp conditions. Avoid placing trays near drafty windows or heating vents. A small fan circulating air can reduce humidity buildup and promote stronger stems, especially in compact indoor spaces.

11. Use shallow trays with good drainage and a light, fine-textured growing medium.

Microgreens develop shallow roots, so 1–2 inches of soil or coco coir is enough. Overly dense soil retains too much moisture and encourages mold. 

12. Fill seedling trays with care.

Lightly press seeds into the surface without burying them. Microgreens germinate best when the top layer remains moist and receives adequate airflow, allowing roots to establish quickly and evenly.

13. Mist, don’t pour, when watering.

A spray bottle gently wets the soil surface, preventing seeds from being displaced or the soil from becoming compacted.

14. Water consistently for steady growth.

Once seedlings are established, bottom-watering, adding water to the tray below, keeps foliage dry and reduces the risk of disease. The goal is even moisture throughout the growing medium, not oversaturation, ensuring healthy, vigorous microgreens.

15. Harvest at the first true leaves for peak flavor and nutrition.

Most microgreens are ready within 7–14 days, when the first set of true leaves appears. At this stage, both flavor and nutrient content are at their highest.

16. Harvest correctly or suffer the consequences.

Pulling leaves by hand can damage the seedlings and halt further growth. Instead, use clean scissors to snip just above the soil line. For example, radish microgreens offer a crisp texture and peppery flavor at this stage, while waiting too long can result in dulled taste and tougher stems.

17. Rotate trays for even light exposure and uniform growth.

Even under good lighting, the edges of trays may receive slightly less intensity. Rotating trays daily promotes balanced development, prevents stems from leaning toward the light, and ensures consistent color and texture across all microgreens.

18. Disinfect trays and tools between cycles.

Warm, humid conditions encourage mold and bacterial growth, but this can be minimized by rinsing trays with a mild vinegar or hydrogen peroxide solution before each planting. Keeping tools and surfaces clean further prevents cross-contamination and supports healthy, vigorous microgreens.

19. Cover new seeds lightly and maintain gentle warmth.

After sowing, sprinkle a light layer of potting mix or coconut coir over the top of the seeds to help retain moisture. 

20. Cover trays loosely with a plastic bag to mimic greenhouse conditions.

Keeping the environment humid without trapping excess water creates conditions similar to a greenhouse and helps speed up germination. Once the first signs of sprouts appear, remove the cover to allow airflow and prevent slow growth or mold.

21. Choose the right type of light and monitor intensity.

Different crops respond uniquely to the light spectrum and light intensity. For compact, nutrient-dense plants, full-spectrum LEDs with a balance of blue light and warm tones effectively simulate natural light and support strong, healthy growth.

22. Focus on the color temperature of microgreens.

The best lights for microgreens typically have a color temperature around 6,000–6,500K, providing ample light without overheating the growing area. Maintaining the correct temperature ensures consistent growth and vibrant, healthy leaves.

Final Thoughts

Growing microgreens is more than placing a tray under a windowsill or in a garage and expecting it to thrive. By managing light distance, moisture, and temperature, it’s possible to produce crisp, nutrient-rich greens year-round. With each cycle, small adjustments and fine-tuning improve results, ultimately yielding trays of fresh, flavorful microgreens ready to harvest whenever needed.