Why Are My Seedlings Turning Yellow?

Any gardener knows the trials and tribulations of caring for seedlings. They’re very fragile in their beginning stages, and their upkeep can become frustrating.

Seedlings need much care and attention to get to their healthy, green state.  Often you’re left wondering, “Why are my seedlings turning yellow,” or, “Why do my seedlings keep dying?”

yellow leaves on seedlingsPin

You’re not alone – we understand the frustration. That’s why we’re here to help.

How To Determine If The Yellow Leaves On My Seedlings Are A Problem

The first question we have to address is how to identify yellow seedlings.

When healthy seedling leaves go from a beautiful, lush green to a yellow or dull brownish color, your seedlings have taken a quick turn for the worst.

Cotyledons are the first thing to sprout in the germination process of plants. Their whole purpose is to provide nourishment from the seed and begin the development of the plant.

Once the plant grows more leaves, the cotyledons will wither, turn yellow, and fall off, as they’re no longer needed. In this case, yellow seedling leaves are perfectly normal.

Causes Of Yellow Seedlings

Once the cotyledons have fallen off, the larger, more mature true leaves will take over food production for the seedling.

You should see your leaves develop into a dark green color. But, if you find they’re turning a yellow or brownish color, you have a problem.

Several things could cause yellow seedling leaves.

Overwatering

Watering issues are the most common problem gardeners encounter with their seedlings. Soggy soil can do much more harm than good.

When you overwater a plant, oxygen is being pushed out of the soil, resulting in drowning roots. This will cause the roots to rot and leaves to turn yellow.

Lack Of Sunlight

One of the most important aspects of growing a healthy plant is making sure it receives enough sunlight. If you’ve placed your seedling in a dark room or area, you can’t expect it to grow into a healthy, green plant.

Be careful using artificial lights. There’s no need to splurge on fancy lamps for your plant to grow properly; natural sunlight is enough.

Too Much Sunlight

Just as too little sunlight isn’t good for your seedlings, neither is too much sunlight.

Your seedling leaves will “sunburn” and whither if they’re exposed to too much sun, giving them a yellow appearance.

Insufficient Soil

If the soil doesn’t provide enough nutrients to the seed, the seedling leaves will turn yellow and die. Similarly, if the soil isn’t situated correctly in the planter, the roots can rot from a lack of oxygen.

Improper Fertilization

While fertilizer is not necessary for a seedling, it can stimulate growth in your plant by providing the soil with nutrients. A simple balanced 10-10-10 fertilizer is a good starting plant food.

But it’s important not to go overboard with fertilizer. Excessive fertilization will strangle the plants’ roots, cause fertilizer burn and prevent them from growing.

How To Prevent Seedlings From Yellowing

If you’ve identified one of the above mistakes as a potential cause for your seedlings turning yellow, there’s no need to worry. We’ve provided some solutions:

Overwatering or Inadequate Watering Practices

To solve overwatering, make sure your soil is never soggy and drain the plant’s excess water.

Allow the soil to dry between waterings. It will prevent your plant’s roots from drowning.

Lighting

When it comes to lighting, it’s as simple as keeping an eye on how much light your plant is taking in. Not too much and not too little.

Don’t place your plant in an area that receives no natural sunlight, but avoid burning the plant from too much sun.

Using A Bulb or Grow Light

If using a bulb, place your plant directly under the artificial light – about 2″ or 3″ inches away from the bulb. Leave your plants under the light for about 12 to 16 hours per day (depending on the plant type).

Then, give your plant a break and place it in a dark area for at least 8 hours.

Replacing The Soil

Sometimes, the solution to reviving a plant is as simple as replacing the soil. Often, the starting soil isn’t nourishing the seed as it should. Using a quality seeding soil mix can prevent this from happening.

Using Fertilizer

If you’re still having trouble giving your plant enough water and sunlight, you might want to look into using a fertilizer.

To ensure you’re fertilizing your plant correctly, consider looking into a soil testing kit. Soil testing will help identify any nutrient deficiencies or excess essential nutrients. It will measure the soil’s pH levels and help you determine how often to fertilize your soil. And when in doubt, a general rule of thumb for gardeners is to fertilize your seedlings every two to three weeks using a balanced liquid fertilizer. That way, they receive the proper minerals they need to grow without overdoing it.

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