How to grow seedlings with strong healthy stems under lights?

[wsmoak]

I started broccoli and spinach seedlings, and instead of strong vertical stems, they're sort of laying over or S-curved.

I don't think it's "damping off" which I've read about -- they aren't dying, they're just laying over sideways a bit.

My theory is that I have the lights too close to the plants.

How far above the top set of leaves should the lights be?

What else do I need to watch out for?

-Wendy

 

[silkiechicken]

I put the lights about 1 inch from the top of the seedlings. I find that they get long necks when started inside, largely because I put the seed about 1/8 of an inch under, while outside, they very well and often end up about 1/2-3/4 of an inch if not more deeper. This shallow planting that happens inside is what I think gives them that long neck... here at least. The seeds I accidentally have fall down the sides of containers pop up with leaves just at the surface as if they are outside.

To combat this, I just start everyone out in a flat, and transplant them into their own container up to their cotyledons just a few days after they fatten up a bit.

If you move the light away, they will just get longer. With plants like tomatoes under lights, a fan on them a few hours a day toughens them up.

 

[digitS']

Those were my thoughts, Silkie': Not enough light causes stretching.

Wendy, you may not be able to move the lights close enough and their environment is too warm. That is something that you may be able to deal with the easiest . . . maybe .

I don't usually set up lights for the seedlings, just use a large south window. Since, I can close doors and vents to allow this room to cool - it works fairly well.

Seedlings are usually grown at between 58F and 68F in a greenhouse. Besides all the natural light, they may even have supplemental lighting. It is often difficult for someone at home to duplicate the growing conditions in a commercial greenhouse with all that light.

If you have less than optimum light - lower the temperatures - the plants will do less stretching.

Steve

 

[wsmoak]

Thanks. I think they have enough light...


110209_4489 by wsmoak, on Flickr

I had the lights lower; I'll put them back down.

Unfortunately I have no sunny south-facing windows, there is a porch on the south side and LOTS of trees.

The house stays 60-65, but it is warmer under those lights, around 70F.

I set up a fan across the room and it's down to 68F. If that's not enough I can move them closer to the glass door, it's colder there. The fan is going to drop the humidity though.

Here is what the sideways seedlings look like:


110209_4490 by wsmoak, on Flickr

Thanks for all the advice so far! The tomato seedlings have *just* emerged and I'd really like them to turn out well.

-Wendy

 

[journey11]

The tops look like they're going strong. Possibly the seed needed to be planted a little deeper (I find seed starter is so light and fluffy; I usually stick mine just a little deeper than you would to direct seed it in the garden.) Or maybe it was too warm when they germinated and they came up too quickly. Being cold weather crops, they don't need to be as warm as tomatoes or peppers.

But either way, your tops look good and healthy. They won't straighten up, but I think they look strong enough to go on and produce. Your light set up looks good to me and close enough on them to be strong. I'll usually keep mine about 2" of the tallest seedling. If they don't touch the bulb, they won't burn.

 

[silkiechicken]

Ah, yeah, that stemy part is usually what is under ground as far as I know. Didn't think too much about the temp, but that would be another compounding issue with indoor growing. When jan rolls around, our apartment temp goes from about 64 to 70 because I've got the egg incubator and 3-4 lamps going.... I take everything home eventually, but it gets warm inside for those few months. LOL Who needs heaters if you can grow stuff?

That said, leaves look good, and when mine get to about that size, I harden them off by setting them outside in the daytime on the north facing balcony. Down here, I only have a north facing balcony to grow things on, but things seem to do ok.

 

[digitS']

Wendy, I don't see a lot wrong with those spinach plants.

My broccoli seedlings tend to drop over some. I've been concerned about it each year but they always seem to pull out of it and grow.

A plant can be productive and still not be a perfect specimen of stalwart planthood. Indoor life, even if it is just for a few weeks, is a bit unnatural for them. Of course, outdoors in the cold is a strain or even, impossible.

You may be doing as well for them as is possible at the moment.

Steve

 

[Organics North]

That spinach does not look bad to me!
I find spinach is very tough to start indoors without a spindly stem.. Even with 5000 lumen per square foot!

Here is some thoughts:
Maybe rotate the trays to keep them moving different directions. Also look at the reflectors on those lights see if you can improve on them to get a little better light spread. (Tape some mylar up on them.)
ON

 

[desertcat]

I'm far from being an expert on broccoli, but the seedlings I bought last year and the ones I started this year, have both been pretty floppy until they got a really good root system. Then they've developed straighter and stronger stems.

 

[wsmoak]

Here's an update from yesterday, just before I planted them in the garden:


110302_4597 by wsmoak, on Flickr

As someone suggested, I think they were not planted deep enough, as that darker colored part of the stem ought to be under ground. Hmmm... I started them in a flat and carefully scooped them out to place in the 4" pots. Am I supposed to cover them all the way up to the cotyledons at that point, or perhaps leave the pot 3/4 full and fill it more later?

Thanks,
--
Wendy