Green Onion Plants Became Limp and Died

Asked February 22, 2016, 2:11 PM EST

Hi! My friend and I have been growing green onions in planters in our school classroom for a research project. We had planted them in Miracle-Gro soil, water them every day (except for weekends but we give them extra water on Fridays), and placed them next to a large window. We had grown them for about 6-7 weeks when we came back from a weekend and noticed that they were definitely dead or dying. Personally, I garden at home but I've never dealt with green onions or container plants. We did some research as to what might help the plants grow better when we plant them again but we haven't been able to find anything that directly relates to our problem. We had our plants set-up in two separate containers, each with 4-5 holes on the bottom, and sitting in larger black containers. They were planted about an inch or two of soil and we put several seeds in each of the holes we made. The plants took about a week to germinate and then started growing well, with them all growing upwards. After a few more weeks the green onions stopped getting any wider and became limp. We pulled a couple out to discover that they had no, or very thin, roots. What are we doing wrong? We were wondering if they needed more sunlight or hotter temperatures? Or, if there was a different soil or a fertilizer we should use? For our project, we won't need to actually harvest the green onions, but we will need them to be healthy and growing as we expose them to different substances. The photos I attached show the plants when they were growing well, they've since become limp and are laying down across the soil.

Bergen County New Jersey onions vegetables seedlings indoor onion transplants

1 Response

When seed starting indoors you have to consider the potting medium, the containers, lights, and watering.
There are many types of Miracle Gro Soils and you did not mention what you used. Avoid dense heavy potting mixtures and garden soils. It is recommended to use a soilless mixture which is a mixture of peat moss, perlite, vermiculite, with small amounts of fertilizer, and lime which promotes good drainage.
The containers appear to be too deep for the seedlings. You can use the shallow seed starting trays underneath the window box containers as long as they have holes for drainage. Once the seedlings germinate, place the transplants 1 to 2” beneath a light fixture for 14 to16 hours a day. Attaching thin chain or wire to either end of your light fixture will allow you to raise and lower the tubes. If the lights are too far away from the transplants, then they will be leggy. It is okay to trim the tops if they do get a little leggy.
Watering every day may be too much. Water to keep the media moist, but not wet. It’s OK if the surface of the growing media dries a bit.
Sounds like you will have to start over. See our website for step by step information on Starting Seeds Indoors, Videos, Options for Lights, and our Vegetable Profile on Onions. Good Luck.