Hello Aaron,

I am no expert, but I notice what looks like Algae in your middle photo. That stuff can be very harmful to your seedlings. Your bottom photo shows new seedlings with very little root volume available per seedling. Those will need to be re-potted to larger pots almost immediately. I now start my seeds in 3-inch square pots to give me a little more time before needing to re-pot them. You can click the photo to see a larger version, and then click the X in its upper-righthand corner to dismiss the larger photo.

The larger zinnias in that photo are in serious need of being repotted to larger pots. My next larger pots are 5-inch square pots. I have been doing this for years, but I still have an awful lot to learn. You might want to purchase one or more books on the subject of gardening under lights.

None are as up-to-date or detailed as I would like, but one I like is Gardening Under Lights. That is a clickable link.

ZM (not associated with any product or vendor mentioned or linked)

Sorry, I missed your question until now. And, you may have already figured out that while LED lights don't put out much heat, the light intensity can be too much for some plants. Seedlings like bright light, but there is a difference between bright light and full sun. And, the intensity of LED lights varies by how close they are to plants. Plants at 18" from a light source still get about half as much light as they would at 6". At 24" the same plants would get around 38% of the light output.

You should start with all your lights set at their highest and slowly lower them if the seedlings start to stretch.

@zen_man - yeah, have been dealing with a considerable amount of Algae. I'm not sure how to deal with it since I'm wanting to keep the lids on for seedlings to start up. Even so, the ones that are not covered have some on them too. I read that sprinkling cinnamon can fight the Algae. I have also started circulating air in the room but still having some issues.

Algae growth is usually because the soil medium never dries. Fertilizer, especially nitrogen and phosphorus, can help algae become a problem. Allow the soil surface to dry between waterings. Increased air flow will help. Mix any fertilizer at 1/2 strength for seedlings. Good luck.

I'm growing Szechuan Button also. Did you move the seedlings after they sprouted? That burn looks more like drying out or fertilizer burn. Light burn doesn't look like that to me. The Szechuan Button does stay very light green. Both that and the Kirigami Oregano have the same light green almost chartreuse color to the leaves