Seedlings germinated but aren't growing - Ask Extension
Hello, I sowed a variety of seeds in Espoma seed starting mix in early April, and they all germinated very quickly. However, they grew just a little ...
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Seedlings germinated but aren't growing #870241
Asked May 27, 2024, 9:57 AM EDT
Hello, I sowed a variety of seeds in Espoma seed starting mix in early April, and they all germinated very quickly. However, they grew just a little bit and have remained in a state of arrested development. The petunias, which I never had trouble with in the past, are miniscule; the size of the head of a pin. I blame this problem on the Espoma seed starting mix, which has become dry and compacted, although I spray the seedlings to keep them from drying. I have read some reviews from other people who have had the same problem with this particular brand. I normally use the Miracle Gro seed starting mix, but thought I'd give the Espoma a try. My question is, what can I do to salvage these seedlings and help them grow? Thank you!
Montgomery County Maryland
Expert Response
When you mention spraying for moisture, are you watering thoroughly, so extra water drains out of the pots or tray, or just misting with a handheld sprayer? Misting alone is not enough to keep the root zone of the seedlings moist enough, and germinating seeds are not very tolerant of drying out for very long.
The potting mix itself is not likely the only (or even a major) factor, but it's hard to rule it out without more information. What does the bag list as the components of the mix? For example, does it contain peat moss, coco coir (coconut fiber), mushroom compost, "forest products," or other ingredients? Mushroom compost, for example, can sometimes be high in "salts," which are mineral deposits that can effectively burn roots on sensitive plants, akin to over-fertilizing. Did the bag contain any time-release fertilizer? If so, was the bag old or was it stored in the hot sun (say, from last year's supply)? If so, some time-release fertilizers are vulnerable to releasing lots of nutrients in hot conditions, rather than metering it out more gradually every time the pellets are watered. Some seed-starting mixes don't contain fertilizer, so it's helpful to check. We would expect salt burn to stunt plants but also to scorch leaves, so if the foliage looks normal, this might not be a factor. Have you tested pulling-up a few seedlings to check their roots?
Are the seedlings under grow lights indoors, in front of a window indoors, or are they in containers outside? If under grow lights, about how long are the fixtures turned on each day?
Can you share photos of the setup and how the seedlings look currently? That may help us to determine what might be going on and how to proceed to nudge more growth. Other than petunias, what other types of seed were sown?
Miri
The potting mix itself is not likely the only (or even a major) factor, but it's hard to rule it out without more information. What does the bag list as the components of the mix? For example, does it contain peat moss, coco coir (coconut fiber), mushroom compost, "forest products," or other ingredients? Mushroom compost, for example, can sometimes be high in "salts," which are mineral deposits that can effectively burn roots on sensitive plants, akin to over-fertilizing. Did the bag contain any time-release fertilizer? If so, was the bag old or was it stored in the hot sun (say, from last year's supply)? If so, some time-release fertilizers are vulnerable to releasing lots of nutrients in hot conditions, rather than metering it out more gradually every time the pellets are watered. Some seed-starting mixes don't contain fertilizer, so it's helpful to check. We would expect salt burn to stunt plants but also to scorch leaves, so if the foliage looks normal, this might not be a factor. Have you tested pulling-up a few seedlings to check their roots?
Are the seedlings under grow lights indoors, in front of a window indoors, or are they in containers outside? If under grow lights, about how long are the fixtures turned on each day?
Can you share photos of the setup and how the seedlings look currently? That may help us to determine what might be going on and how to proceed to nudge more growth. Other than petunias, what other types of seed were sown?
Miri
