“What’s Wrong With My Seedlings?”: A Troubleshooting Guide
If you’re struggling with some seedlings this year, you’re not alone - even experienced growers have some crop failures each year! Seeds can be finicky things, and while some varieties are more forgiving than others, many are quite specific about what they need in order to thrive. In this article, we break down the most common problems and their solutions.
“It’s been weeks, and my seeds haven’t germinated!”
Some seeds are very slow or sporadic to germinate - it’s not uncommon for a few varieties to take 3-4 weeks or more. But if you’ve patiently waited nearly a month and still haven’t seen signs of growth, it is probably due to these common causes:
Inadequate moisture levels. The cell tray should be misted regularly so that it doesn’t ever become bone dry, nor should it ever be completely soaked (the seeds can rot). This is probably the most typical cause for no germination.
Seeds planted too deeply. If the seeds are planted deeper than recommended, it can be tricky for them to break through and sprout. Most cut flower seeds get planted approximately 1/8-1/4” deep, although some varieties need to get “surface sowed” as they need light to germinate - like scabiosa, snapdragons, and celosia. Be sure to follow package directions.
Temperature too warm or too cold. The majority of cut flower seedlings do best at room temp or a bit warmer than that, and may germinate better with a heating mat underneath the tray. However, cool-weather varieties (typically flowers that bloom in springtime, like sweet peas) will germinate best in much cooler temperatures.
And sometimes, it’s just an issue with the seed supplier… and we don’t judge you one bit if you want to blame it on this, lol.
“My seedlings are too tall and falling over!”
“Leggy” seedlings are a common issue among home growers, and this is due to the seedlings not getting enough light. Generally speaking, only the sunniest south-facing windowsills are going to provide adequate light for seedlings kept indoors - and even then, we typically recommend the addition of a grow light for about 12 hours per day. If growers are using exclusively grow lights, it’s important to ensure that there are enough grow lights and that the trays are placed close enough to the light. Unfortunately, it’s impossible to provide specific distance recommendations here because it depends on the light’s wattage and size - but if the seedlings are becoming lanky, that’s a good indication that they’re not getting enough light.
When recognized early enough, and promptly given more light, leggy seedlings can beef up and still thrive. In the plant world, we are always aiming for wrestlers, not basketball players - the stocky seedlings are going to be the healthiest, most productive, and yield the best blooms for you!
“Uh oh, my seedlings’ leaves have started to turn yellow?”
This is one of the trickiest ones to diagnose and remedy, because it can be due to a variety of factors, including:
Improper watering - typically due to too much (as opposed to not enough) water! Since growers are so afraid of underwatering their beloved seedlings, some accidentally water them too much. This can cause the leaves to look droopy, soft, and start to turn yellow. If this sounds like your plants, let the tray of seedlings dry out a bit more between watering, and you should notice improvements within a week or so.
Nutrient deficiencies. This is likely the case if it’s a slow-growing seedling that has been in a cell tray for a long time, and has yellowing leaves and stunted growth. A lack of nitrogen is the most likely culprit and, thankfully, they’ll likely perk up once transplanted to the garden. Be sure to first amend your bed’s soil with a balanced, organic fertilizer or mix in some compost, and they should bounce back quickly.
“They looked great in the tray, but then I transplanted them to the garden and now they’re wilted!”
Transplant shock is a common and frustrating issue with some flower varieties (I especially struggle with Sweet Peas, Iceland Poppies, and Zinnias in this way) but the good news is that most plants recover after the first week or two. Some plants are especially vulnerable to transplant shock, which refers to the adjustment period while a plant establishes its roots in a new growing location. The plant may look extremely unhealthy for a few days or a week while it acclimates to its new environment - it’s not uncommon for them to be yellowed, wilted, or leaves to drop. After a few days in their new location, though, most will recover just fine.
Transplant shock can be minimized by properly hardening off your seedlings, handling them very gently, transplanting them on a mild day (e.g. not during a storm and not during the hottest day of the season) and watering them well.
A healthy delphinium seedling getting transplanted to the garden
