Another Spring of slow-growing indoor vegetable seedlings

[robrocke]

I feel like every year I've been adding one more new element to my annual Spring seed-starting regiment, but again this year after initially germinating quickly I am seeing slow subsequent growth. Here is a photo of my seedling tray (a mix of tomatoes and peppers as well as basil, borage, and amaranth) at about three weeks:

My seed-starting setup is located in a cool, unheated basement in the 60 degree range. I live in zone 7A.
1. First I added artificial grow lights that I place a few inches about my seedling trays as soon as they germinate.
2. Then I added a heat mat that I've been leaving on until the seeds first germinate.
3. Finally after feedback in this forum a couple of years ago I've been using a high-quality organic seed-starting mix.

Most of the seeds germinate quickly, although this year neither my Marigolds nor my Husk Tomatoes/Ground Cherries have sprouted at all. But the seedlings seem to grow so slowly after that.

A couple of thoughts/questions:
1. Is the ambient temperature in my basement an issue, and if so how I might remedy that? (It's really the best place for my seed-starting setup space-wise.)
2. Should I be leaving the heat mat on longer than just until initial germination? (I start a variety of plants in the same trays so the germination times are pretty variable. I'm always torn whether I should be turning the heat mat off for one set of seeds that have germinated or leaving it on for the other ones that have yet to germinate.)
3. At what point should I be feeding the seedlings? Historically I've been waiting for the first true set of leaves.

Any other helpful suggestions are welcome.

Thank you!

 

[Chuck]

I feel like every year I've been adding one more new element to my annual Spring seed-starting regiment, but again this year after initially germinating quickly I am seeing slow subsequent growth. Here is a photo of my seedling tray (a mix of tomatoes and peppers as well as basil, borage, and amaranth) at about three weeks:
View attachment 52303

My seed-starting setup is located in a cool, unheated basement in the 60 degree range. I live in zone 7A.
1. First I added artificial grow lights that I place a few inches about my seedling trays as soon as they germinate.
2. Then I added a heat mat that I've been leaving on until the seeds first germinate.
3. Finally after feedback in this forum a couple of years ago I've been using a high-quality organic seed-starting mix.

Most of the seeds germinate quickly, although this year neither my Marigolds nor my Husk Tomatoes/Ground Cherries have sprouted at all. But the seedlings seem to grow so slowly after that.

A couple of thoughts/questions:
1. Is the ambient temperature in my basement an issue, and if so how I might remedy that? (It's really the best place for my seed-starting setup space-wise.)
2. Should I be leaving the heat mat on longer than just until initial germination? (I start a variety of plants in the same trays so the germination times are pretty variable. I'm always torn whether I should be turning the heat mat off for one set of seeds that have germinated or leaving it on for the other ones that have yet to germinate.)
3. At what point should I be feeding the seedlings? Historically I've been waiting for the first true set of leaves.

Any other helpful suggestions are welcome.

Thank you!

Your plants are leggy and will get leggier because they aren't getting enough light. The 60 degree temps are too low for good growth. Leave the heat mat on @ about 75-80 degrees 24/7. I start to feed my seedlings when the first set of true leaves are fully formed although it won't matter much if you wait until the second set start to form. Leggy plants are weak plants as far as fungus is concerned and damping off disease is more prevalent in their present situation than otherwise.

 

[vette-kid]

Too cold, and peppers are slow starters anyway.

 

[tNtRanch]

I agree with the heat mat 24/7 I had my plants in 40 degree temps but with heat mat they seemed to do well. My peppers are slow too.

 

[robrocke]

Thanks for your thoughts and advice. It continues to be a tough Spring for my seedlings, despite hoping that I'm getting better at seed-starting every year. Here are a couple of photographs taken this afternoon (10 May 2019), about 6 weeks after initial planting. After my last post I turned the heat mat back on and have left it on 24/7. Once most of the seedlings had their first "true" set of leaves, I also began feeding them with an organic starter fertilizer at the recommended once every two weeks. Today is only the second time I've been able to start acclimating my seedlings outside. I know - they're not looking so good (yellowing leaves, etc.). I continue to be grateful for any advice and guidance. Thank you!

 

[Chuck]

These seedlings look a lot better than in the first pictures. It looks as if they are missing trace minerals. And of course natural light. All in all they look pretty good. Once outside they will shoot up.

 

[DirtMechanic]

There is an organic fertilizer by Espoma for tomato called tomato tone. It has a low nitrogen value and components like greensand for trace mineral supplements. I think it is a good general fertilizer too.

 

[TomatoNut]

If your tomato seedling remain leggy, plant them deeply in your garden. It will help make a stronger plant.

 

[headfullofbees]

Your plants are running out of nutrients: in order to get them taken up quickly, use a liquid feed (not miracle-gro) preferably made from tea extracted from composted pelleted poultry manure, or cattle/horse manure (which you can make in a few hours) or your urine, diluted 10-1 with water, to which has been added the requisite dose of seaweed extract.
Your tomatoes are not leggy, they are fine.

 

[TomatoNut]

Pay no attention to headfullofbees, robrocke when he tells you not to plant leggy things deep. Plant deep!! However, he's not wrong about the fertilize. But Miracle-Gro does offer organic products.

 

[DirtMechanic]

I always considered the holes I make as deep, but then I lays the plants in sideways after having mixed in fertilizer and soil at the bottom of the hole. Does that make me a dual citizen of the plant deep and plant shallow camps?

 

[TomatoNut]

Well at least you're not against planting deep.

 

[headfullofbees]

Not doing it though.

 

[TomatoNut]

Look, you plant your tomatoes on top of your house for all care. But planting deep is the best thing to do for leggy tomatoes!

 

[headfullofbees]

Look, you plant your tomatoes on top of your house for all care. But planting deep is the best thing to do for leggy tomatoes!

Look, if you want to argue with me, disrespect me, call me names, whatever you like, it's OK, I'm big enough to take it in good humour, and won't complain.
I also hope the management will see that I'm not injured or upset, and cut you a little slack whilst you get experienced on this forum.
Having said that, do you think it's fair to post unproven advice to others merely to spite me?
They have done you no harm, even if you believe I have.