Quick one - first ever grow

I’m not a pro here. It’s the end of week three and been watering when the top of the soil appears to be drying out. Under a cheap LED grow light for 16 hours a day. Day 15 I thought I’d snapped the seedling so I propped it back up with soil and it has continued to grow. Day 20 I fed the plant with a cheap tomato fertilizer I bought in the UK. Water with rain water collected outside. Bought a cheap ph meter that doesn’t work so it’s going well so far. Will continue to feed once a week. This really is a trial to see if I can grow without being a scientist.