Q.Zinnia seedling leaf curl
8weeks old zinnia seedlings! Some of them are doing very well but most of them have the bottom leaves curling and drooping downwards! Im using universal potting mix and no fertiliser because im scared i will end up over fertilising them. First is healthy one with leaves still horizontal position, havnt repotted it yet, the second pnes i repotted

Certified GKH Gardening Expert
This appears to be a classic case of overwatering. If the soil stays moist for more that two or three days at a time, then it is way too wet.
Make sure to let these dry out very well between watering. Since these were started in such a large container, there will be a lot of soil that stays wet for long periods. There are not enough roots to pull that water out, so it will sit in the soil, and likely cause rot.
I would only repot to what it needed to keep the seedling alive for a few weeks, and then transplant. This will prevent overwatering, and will allow the soil to dry out enough to prevent issues in the future.
This article will give you more information on the care of these: https://www.gardeningknowhow.com/ornamental/flowers/zinnia/growing-zinnia-flowers.htm

The larger pot has been very wet! Thanku!! Im thinking of mixing pertile to the potting mix, would that help soil dry out fast?