I’m not trying to grow sprouts . . .

Cabbage and broccoli seedlings

Cabbage and broccoli seedlings

This is the first year I’ve attempted to start seedling indoors, using heat mats and grow lights. My set up includes two shelves with heat mats, on top of which I’ve placed covered seedling starting trays.  These sit under red and blue LED grow lights. 
So far, I think my results have been mixed at best.  With this set up, germination happens really quickly.  Within just a few days, the seeds start sprouting.  But, pretty much everything I am growing looks like it is attempting to actually become sprouts or micro greens. I’ve started lettuce, cabbage, broccoli, and two different varieties of onion.  The onion seedlings look best, though a bit floppy. As you can see in the picture, the cabbage and broccoli seedlings look pretty “leggy.”  As I said, this is my first time trying to start seedlings indoors, so if you have experience doing this, let me know if you think these look right . . . or not.  If not, any suggestions? 


Happy gardening!


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13 Responses to I’m not trying to grow sprouts . . .

  1. DoubleD says:

    How close to the plants do you have the lights? I keep mine practically on top of the plants and it helps alot to reduce the legginess. My kohlrabi starts are a bit leggy – but not as much as yours are appearing to be. Are the lettuces “stretching” too? How do the onions look? If all of them are “reaching” then you probably have your lights too far from the seedlings (only an inch or so is best) OR… those LED lights may not be providing enough light to grow them out properly. I hope if is the first and not the latter.

  2. Thanks DoubleD. Great suggestion! There is about 10 inches between the plants and the lights. I’ll move them closer. Another question. Do you keep the heat mat on the whole time the seedlings are under lights or do you turn it off after germination?


  3. Edward says:

    Your lights are definitely too far away. Once the seeds have sprouted, I would turn the heating mat off. You don’t want them to get used to being warm all the time. Once they go outside they will have cooler roots. That could also be adding to your legginess.

  4. Thanks Edward!

    So now I am wondering if this batch is a total loss and I need to start over . . .


  5. DoubleD says:

    I turn the heat mat off once the plants have all emerged satisfactorily. Since I just reseeded some cells that did not germinate – I will keep it on for two more days – and then turn it off.
    I think you may be able to save the plants you currently have. You can start more later (up to 3 weeks from now) and be fine – so I would not rush to give up on them.

  6. Susy says:

    I agree with everyone else. You want your lights right on the plants, they’re stretching toward the light.

    One this that also works well in seed starting is to have a small fan that circulates the air around the plants, it helps them become stronger and it also helps keep fungus down.

  7. Dan says:

    Seems like most things have been covered. I hate to say it but you may want to start over. It looks like they are almost 3″ tall and have only developed seed leaves.

    What date do you plant them out in your area?

    Can you provide any additional light from a south facing window?

  8. Dan, these seedlings are just a week old. They sprouted within a couple of days. I have more space under the grow lamps and could get another batch started easily enough.

  9. Dan says:

    Well see how they do first. I believe you are from the PNW like Sinfonian right? If so you should transplant cole crops out the first week of April and start them from seed inside Late Feb/Early March. If they don’t start to stock up just start some more around those dates.

    Also if you can provide natural light on top of the grow light it would help, along with putting the light right above the plants. You can possible grow them in your greenhouse too with the heat mat on. Cole crops only need temps of around 65f to grow.

    The onions you are growing can also be regularly trimmed to within 4″-6″ inches to keep them in order. It is actually beneficial for onions to be trimmed as it stocks them up and they produce more leaves.

  10. Yes, Dan, I am in the PNW. I’m following the planting schedule outlined by DoubleD since she is in the PNW as well. We both have greenhouses so I am following her plan for indoor starting and then transitioning to the greenhouse.

    Thanks for the onion trimming suggestion. I had no idea about that.

  11. Sinfonian says:

    Looks like I’m late to the party. Sandy, don’t worry, this happened to me last year too. Good news though, you HAVE a setup to start over and you are only a few weeks behind your perfect schedule, which is flexible. I didn’t, I tried the window sill method (bad idea).

    I agree that it would be good to start a new batch. Go ahead and work with these too. Think of it as succession planting. I planted my broccoli out leggy and it survived, as did my green onions. My cauliflower didn’t work, but I could have done something wrong. Everything was new to me last year.

    Good luck, I look forward to seeing what the LEDs do when they’re an inch away from the tops of the plants.

  12. Pingback: Tomato before & after and plum in bloom « The Zero Fossil Fuel 10 Year Challenge

  13. ginag says:

    My broccoli sprouts are leggy, too, and in full sun at a southern window. How did the leggy ones do once transplanted?

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