Why Are My Microgreens Yellow? (Solved & Explained!)

You’ve decided to start growing your own delicious, nutrient-packed microgreens yourself. Good for you! I mean it, they are so good for you! But you’ve noticed that what are supposed to be micro ‘greens’ are looking sort of micro ‘yellows.’ Alex Lafreniere from Plant Hardware tells us that the yellowing, or Chlorosis, is caused by a lack of chlorophylls, the parts of a plant that absorb and reflect light.

Lafreniere, a microgreens producer, suggests that this yellowing may be because your plants are receiving too little or too much light and therefore are not producing the chlorophylls. These chlorophylls absorb yellow and green light waves from the sun and reflect green light waves. That is why we see the color green. When there aren’t enough chlorophylls, we see the reflected yellow waves.

The rest of this article will go on to discuss common issues and solutions when growing microgreens.

What are the other causes of yellow microgreens?

If you think you have been giving your microgreens the perfect amount of sunshine, then you may be wondering what other reasons may cause your microgreens to yellow. Lanfreniere states issues with fertilizer, soil pH, watering, aging, pathogens, and root damage may also cause plant yellowing, however, it is less common with seedlings and therefore unlikely the cause of yellow microgreens.

What is a blackout period?

A blackout period is a time when your microgreens are not exposed to sunlight or other light sources. This ensures that your microgreens are not overexposed to light and produce an adequate amount of chlorophylls to be healthy and green. Soak and Soil suggests that you should make sure that your microgreens should have 12 hours of dispersed light and 12 hours of darkness daily.

Will my yellow microgreens turn green?

Depending on why your microgreens are yellow, there may be a chance that they could turn green again. Plant Hardware tells us that if your microgreens have been exposed to too much light they may become green when moved into a less intense light source.

If your problem was related to pathogens that interfere with plant functions, this is likely not reversible. If inadequate nutrients are the cause, it is potentially reversible depending on the nutrients themselves. Some nutrients may be locked in place while others are able to move throughout the plant.

Are there any microgreens that should be yellow?

Microgreens can actually come in an array of different colors and you may find some that are meant to be yellow such as popcorn kernel microgreens or yellow beet microgreens. Sometimes, it may be the entire sprout and, sometimes, it may just be the stem or the veins that are yellow.

Having microgreens of different colors offers a visual pallet when creating colorful meals or dishes. They may also have a different taste if you allow them to remain yellow by limiting their sun exposure. For example, popcorn microgreens may taste sweet.

How can I prevent my microgreens from turning yellow?

Ensure that you are giving your microgreens the appropriate amount of light and blackout periods. Be sure not to overwater or underwater your plants. Give them a little bit of water at a time and test monitor how much is appropriate for your plants. Finally, ensure that their soil has nutrients without over-fertilizing them. These fertilizers can build up in a plant and actually do more harm than good.

What are the common problems when growing microgreens?

It isn’t uncommon for many microgreen beginners to see a variety of issues when starting out. Microveggy lists some common issues such as mold or mildew, falling over, slow germination, uneven growth, yellowing, and dirty harvesting.

What causes mold or mildew?

A variety of factors related to moisture could cause mold and mildew on your microgreens. For instance, overwatered soil, high humidity, and overseeding may all lead to this issue. You can prevent this by not overwatering, ventilating, and avoiding planting too many seedlings at once so that they aren’t growing tightly packed together.

Why are my microgreens falling over?

Weak, wilting microgreens can be disappointing because they tend to lack that crispy crunch that we associate with vegetable freshness. If you notice that your microgreens are beginning to fall over to one side it is likely because of underwatering.  

Why aren’t my microgreens germinating?

The germination period for most microgreens is about two to three days. Some may take longer depending on the kind of microgreen. If your microgreens aren’t germinating, give them more time.

One way to speed up the germination process is to presoak your microgreens to wake them up from dormancy before planting them. Weighting the seed with a covering or thin layer of soil will also benefit their germination.

What causes uneven growth?

Have you ever noticed that your houseplants often grow towards the window? That’s because your intelligent plant knows to move towards its energy source, the sun. If your microgreens are growing unevenly, it is likely because some of them are getting more light exposure than others. To fix this, be sure to rotate your container and ensure that all of the greens are getting the same amount of light.

How can I prevent dirty harvesting?

As mentioned above, you can increase your microgreens’ germination rate by covering with a thin layer of soil. However, this can sometimes lead to dirty sprouts at harvest time. Microveggy suggests adding a layer of loose soil followed by a layer of compacted soil. As they grow, this top layer will allow for the microgreens to push through without carrying excess dirt.

Growing your own microgreens is a very satisfying process, especially when everything goes right. However, it usually takes time, experience, and learning from your mistakes to grow the perfect microgreens that are green, crisp, and fresh.

If your microgreens aren’t looking so great, take some time to investigate the issue and try again. With a little bit of curiosity and patience, you too can grow delicious microgreens.