Tomato seedlings not growing?

[Dirtmechanic]

They’re under grow lights 14 hours in a room ~70 degrees

fyi: my pepper seedlings are doing the same thing as the tomatoes. I have sugar snap peas in the same conditions that are doing great, as are my broccoli and cabbage seeds.

So...its a temperature thing according to your own words and what your plants are indicating. The plants you have that are cool season tell us why the hot season plants are struggling. Perhaps separating them and intensifying the toms and pepper environment to 80f will improve them markedly, but then the cooler season veggies may begin to balk.

 

[Coolbreeze89]

This is my old starter set-up. What I want to point out is the white paper hanging from the sides to reflect the light back to the plants. That made a lot of difference in how leggy they got. They grow to the light so if the light is coming from one direction they grow in that direction.

View attachment 34436

Expect your tomatoes to grow a lot faster than the peppers.

I’ll add a white sheet to my setup - I have some old plastIc that would be perfect!

 

[Coolbreeze89]

@majorcatfish : I’m using4 of these: Osunby LED Grow Light 45W UV IR

 

[majorcatfish]

@majorcatfish : I’m using4 of these: Osunby LED Grow Light 45W UV IR

i'm not really revised in led lighting, so my advice might not work for you...will be keeping an eye on your progress

 

[Coolbreeze89]

i'm not really revised in led lighting, so my advice might not work for you...will be keeping an eye on your progress

Thank you.
Based on everyone’s suggestions, I’ve:
-added white panels to reflect more light inward
-increased the temp of the tomatoes and peppers to about 80-85
-I haven’t added any fertilizer yet, but will do so once true leaves form
-I’ve told myself to be patient! That’s the hardest one!

 

[YourRabbitGirl]

This is the first year I’ve started seeds indoors. My tomato seeds sprouted, grew two leaves...and stalled! They’re under grow lights 14 hours in a room ~70 degrees, in organic potting soil. I water when the soil starts to get dry, from below. I moved them up from a seed tray to a 3” peat pot a couple days ago, and they had lots of root growth (when I transplanted them, I buried most of the stem as they were a bit leggy, even with the lights just a couple inches up). They don’t seem to be growing though for the last 10 days or so? Any suggestions? Thanks!

fyi: my pepper seedlings are doing the same thing as the tomatoes. I have sugar snap peas in the same conditions that are doing great, as are my broccoli and cabbage seeds.

To grow tomatoes from seeds, start the seeds indoors 6-8 weeks before the last expected frost. Plant the seeds in small pots using potting soil and place them in a sunny, warm location. Then, lightly water the seeds daily until they sprout.

 

[digitS']

There are several things that I have to keep in mind when it comes time to move seedlings. Foremost is to be careful -- large hands and clumsy digitS'.

There is no choice about disturbing the roots. Through photosynthesis, damage is likely to be repaired. Photosynthesis is mostly taking place in the leaves. The seedlings with healthy leaves can recover from transplanting shock.

Allow the plants to develop their true leaves. At one time, I might have realized the importance of leaves and thought that meant that I should grab them by the stems. Not for me! A Seedling has only one stem. If it is damaged, I've killed it. There is little choice but to hold them by the leaves. I absolutely cannot be trusted with seedlings as tiny as snapdragons. They are in DW's care. Other seedlings like tomatoes and peppers, I can handle but I want to see those true leaves even if I am mostly trying to hold them by the seed leaves.

Temperatures and sunlight should be in balance. Without instruments to measure, it's difficult to know how much light your window is admitting, difficult to know how much is being emitted by lamps. In photosynthesis, heat isn't a replacement for light. Plants aren't warm-blooded mammals although they metabolize nutrients within a range of temperatures. Growth occurs. Adequate warmth with too little light results in plants wandering off, looking for more light. We call that legginess.

Steve

 

[flowerbug]

There are several things that I have to keep in mind when it comes time to move seedlings. Foremost is to be careful -- large hands and clumsy digitS'.

There is no choice about disturbing the roots. Through photosynthesis, damage is likely to be repaired. Photosynthesis is mostly taking place in the leaves. The seedlings with healthy leaves can recover from transplanting shock.

Allow the plants to develop their true leaves. At one time, I might have realized the importance of leaves and thought that meant that I should grab them by the stems. Not for me! A Seedling has only one stem. If it is damaged, I've killed it. There is little choice but to hold them by the leaves. I absolutely cannot be trusted with seedlings as tiny as snapdragons. They are in DW's care. Other seedlings like tomatoes and peppers, I can handle but I want to see those true leaves even if I am mostly trying to hold them by the seed leaves.

Temperatures and sunlight should be in balance. Without instruments to measure, it's difficult to know how much light your window is admitting, difficult to know how much is being emitted by lamps. In photosynthesis, heat isn't a replacement for light. Plants aren't warm-blooded mammals although they metabolize nutrients within a range of temperatures. Growth occurs. Adequate warmth with too little light results in plants wandering off, looking for more light. We call that legginess.

Steve

i don't know why people want to handle them so often anyways. just plant into a few inc h cell pot to begin with and then leave them alone until they're ready to go out into the garden, by then the stems are strong enough to survive the transplanting just fine. i've never lost any to breaking them when they have a 1/4" aka 1cm stem...

 

[Coolbreeze89]

i don't know why people want to handle them so often anyways. just plant into a few inc h cell pot to begin with and then leave them alone until they're ready to go out into the garden, by then the stems are strong enough to survive the transplanting just fine. i've never lost any to breaking them when they have a 1/4" aka 1cm stem...

First on my “do differently next season” list is to skip the plastic cell trays and start with bigger option!

 

[YourRabbitGirl]

So...its a temperature thing according to your own words and what your plants are indicating. The plants you have that are cool season tell us why the hot season plants are struggling. Perhaps separating them and intensifying the toms and pepper environment to 80f will improve them markedly, but then the cooler season veggies may begin to balk.

How to Save Tomato Seeds

1. Rinse tomatoes in water to remove dirt before harvesting seeds. ...
2. Cut open ripe tomatoes one variety at a time and squeeze the pulp, juice, and seeds into a container. ...
3. Pour into a container with a lid. ...
4. Label and set aside the containers for three days at a temperature, not more than 70°F (21°C).