Growing herbs indoors with artificial lights, slow growth

Question

I’ve seeded herbs indoors in windowsill containers (24 in. each), with two T5 lights about 3-5 inches from top of container and the whole setup is surrounded by reflective plastic (like the ones used for car screens). Lights are on a timer, with 12 hs light/12 hs dark.

The distribution is in the first container: Basil – Chives – Parsley – Sage.

In the other container is:
Marjoram – Rosemary – Oregano – Tarragon – Thyme.

In the first container, the seeds were large enough to sow them about 1 in. apart, but those in the second are so small that they’re growing in “clusters. ” I make sure not to over water them and spray a small amount of water every day, making sure the soil is damp but not wet. The containers drain very well through holes in the bottom so I can see if there is much water added, as it would collect in the trays below.

All of them germinated in a week (approx), but except sage, which is doing well. All the rest stay as sprouts forever and almost none have “true leaves. ” Should I thin all of them, how far from each other? What else can I do?

 

 

Thank you so much for your advice.

The potting soil I’m using is (copied from the vendor’s site):organic blend of Canadian sphagnum peat moss, perlite  coconut coir, starter charge, beneficial microbes, 78+ Ionic Chelated Micro-Nutrients and Multi-Nutritional and Organic Compounds. It doesn’t seem go be just a starting soil. They claim you can use it without fertilizer for 3 months. Should I fertilize anyway?

As for the temperature, it is indoors in an AC house at about 75 Farenheit, and 80 F inside my setup due to the 2 lamps (T5’s 24 inches wide).

I’m attaching some photos of my setup responding to the e-mail I received from you. I do not know how to attach photos in this site. Total view  and detail about how different seedlings are growing  (all the small seeds are growing like marjoram).
As I said, the bigger seeds are about 1 inch apart, and the smaller in clumps.

I do not intent to re-pot them outdoors, this should be my source of fresh herbs year round.
You say I should  prick them, but I do not know to what extent:
Should I leave the ones growing at 1 inch as they are, or should I leave just one or two total?
Same thing for the “clumps” should I leave them at about only 1 per inch or just one or two total?

Thanks again for your help

Answer 1

What type of soil did you use? If you used seed starting soil, I would give the plants a little heavily diluted water soluble fertilizer. Seed starting soil has none and could keep them from growing once sprouted.

I would also consider changing your watering from misting to watering from below (setting the pots in a shallow water bowl for a bit to water them). Watering from above can encourage dampening off and also it may only be making the surface of the soil wet and it may not be reaching the roots. If the drainage is good, you should not have problems with over watering.

Finally, how is the temps around the seedlings? Lower temps can slow growth. You may want to set them on a heat source, like a heating pad on the lowest setting with a towel on in. Just to raise the soil temp a bit.

As for the seedlings growing in clumps, this is not an issue. You can "prick them out" when they get their first set of true leaves. Gently remove the clump from the soil and use a tooth pick or something similar to carefully tease apart the different seedlings and repot individually.

Answer 2

Thank you so much for your advice.

The potting soil I'm using is (copied from the vendor's site):organic blend of Canadian sphagnum peat moss, perlite coconut coir, starter charge, beneficial microbes, 78+ Ionic Chelated Micro-Nutrients and Multi-Nutritional and Organic Compounds. It doesn't seem go be just a starting soil. They claim you can use it without fertilizer for 3 months. Should I fertilize anyway?

As for the temperature, it is indoors in an AC house at about 75 Farenheit, and 80 F inside my setup due to the 2 lamps (T5's 24 inches wide).

I'm attaching some photos of my setup responding to the e-mail I received from you. I do not know how to attach photos in this site.Total view and detail about how different seedlings are growing (all the small seeds are growing like marjoram).
As I said, the bigger seeds are about 1 inch apart, and the smaller in clumps.

I do not intent to re-pot them outdoors, this should be my source of fresh herbs year round.
You say I should prick them, but I do not know to what extent:
Should I leave the ones growing at 1 inch as they are, or should I leave just one or two total?
Same thing for the "clumps" should I leave them at about only 1 per inch or just one or two total?

Thanks again for your help