Wet seedlings with some white mold and small brown fungus growing in soil of plants - Ask Extension
Hello.
I have provided detailed background here and my question below. Please scroll to “QUESTION” at the bottom.
I have started seedlings f...
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Wet seedlings with some white mold and small brown fungus growing in soil of plants #929740
Asked April 27, 2026, 9:51 AM EDT
Hello.
I have provided detailed background here and my question below. Please scroll to “QUESTION” at the bottom.
I have started seedlings for my vegetable garden for the summer. The seedlings consist of cherry tomatoes, Roma tomatoes, beefsteak tomatoes, Rutgers tomatoes, jalapeños, big Jim peppers, and banana peppers. I used a seed starting kit and when the seedlings grew their first true leaves, I planted them in 4 inch pots, which was on April 11. I use a variety of types of grow lights, since that is what I have, and I make sure each plant has enough light.
I did put all of the pots into a couple larger container to contain the mess and each pot was touching another pot. The pots are on a 3 tier shelving unit which I kept in a closet behind a closed door to keep pets from having access to the plants. I watered every other day or so and added a little bit of fertilizer for potted plants on April 20th.
This morning (April 27) I needed to move the plants out of the closet and noticed some white fungus on the top of the soil in almost all of the pots and a few pots have this small brown fungus growing around the edge of the pot. The last day I watered was April 24 and the soil all seems wet still.
I have realized I did not give them proper airflow and overwatered. Right now I have spread the pots out and have a gentle fan on them to help dry them out. Someone online said cinnamon can help so in a panic I put cinnamon on top of the soil. This is the orange color in the photos.
QUESTION:
I am planning to dry the soil out as much as possible today and transplant the plants to new pots with new soil, scraping away the fungus and mold. Is this the correct next step for this issue?
Additionally, the stems seem skinny and I do have tall leggy plants. This is not unusual for me in past years due to the variety of grow lights and different distance from the plants to the grow lights. However, some of the plants are really skinny on the stem by the soil and get thicker going up the stem. Is this also common for an amateur set up like mine? Or could this be a sign of something worse?
I have read damping can be a problem in this situation. If damping were to kill the plants, 1. Am I able to defend against damping and 2. When would the plants die?
Last question: should these plants survive and produce vegetables, are the vegetables safe to eat?
Thank you very much for your help. This is not my first time starting a vegetable garden from seeds but it is my first time experiencing the fungus and mold and I am a bit worried. I can send more pictures if needed, I seem to only be able to attach 3.
Montgomery County Maryland
Expert Response
Mold can be very common on moist potting soil, especially (as you noted) when air circulation is poor and humidity may be somewhat high due to the limited airflow. Different potting mix brands use their own blend of ingredients, and some may have materials that happen to be more conducive to fungal growth than others. (For example, those including "forest products," which can be common in many potting mixes and which consists of broken-down wood or bark, could be supporting mushroom growth like the brown gel-textured fungus pictured. The white type of mold is more typical of potting mix fungal outbreaks, and could be growing on any number of materials.) Fungal spores are airborne and can easily contaminate any organic material used to grow plants (generally potting soil), so nothing will remain sterile for long, even if the material was sterilized before the manufacturer bagged it.
If the stems are not succumbing to damping-off (a different fungus than what you've pictured, which usually does not produce visual surface growth), most other fungi appearing on the soil are not going to cause problems for the plant, but as you noted, their presence indicates a need for better airflow and perhaps less frequent watering. There aren't any effective fungicides labeled for indoor use (that is a key criteria) that would be worth trying, nor would they be needed once the plants go outside. You can skip applying any cinnamon in the future, as it's not proven (at least in a kitchen-use form) to have any significant impact on plant fungal diseases or soil-borne fungi.
As for the stem thickness, it's hard to say what is going on, but stems can thicken in response to better airflow and currents that sway the stems in a breeze, since thicker tissues help them stabilize themselves. Stem "legginess" (stretching and often becoming spindly or tipping/leaning over) is quite common when plants are grown indoors unless any grow lights used are quite bright. Damping-off fungi tend to kill the stem tissues at or very close to the soil level, and as such they collapse plants at a very young age, usually well before they reach above a few inches tall.
Yes, the fruits/harvest these plants will produce once they are growing outside will be fine to eat.
Miri
If the stems are not succumbing to damping-off (a different fungus than what you've pictured, which usually does not produce visual surface growth), most other fungi appearing on the soil are not going to cause problems for the plant, but as you noted, their presence indicates a need for better airflow and perhaps less frequent watering. There aren't any effective fungicides labeled for indoor use (that is a key criteria) that would be worth trying, nor would they be needed once the plants go outside. You can skip applying any cinnamon in the future, as it's not proven (at least in a kitchen-use form) to have any significant impact on plant fungal diseases or soil-borne fungi.
As for the stem thickness, it's hard to say what is going on, but stems can thicken in response to better airflow and currents that sway the stems in a breeze, since thicker tissues help them stabilize themselves. Stem "legginess" (stretching and often becoming spindly or tipping/leaning over) is quite common when plants are grown indoors unless any grow lights used are quite bright. Damping-off fungi tend to kill the stem tissues at or very close to the soil level, and as such they collapse plants at a very young age, usually well before they reach above a few inches tall.
Yes, the fruits/harvest these plants will produce once they are growing outside will be fine to eat.
Miri
