Good day! I would like to ask for some help to determine what I am doing wrong in growing my sunflower. The sunflower was started from seed about 3 weeks ago and now it has grown a few sets of true leaves. Lately I've noticed that the lower two leaves have started to wilt and the top leaves are starting to yellow. The seedling was not transplanted. The soil is constantly moist, but not waterlogged. The pot is fairly large about a foot deep, with drainage holes. The soil is mixed with garden soil, compost, coir and perlite. It receives about 4 hours of direct sunlight everyday.
I've tried watering it deeply on the assumption that the leaf wilting is caused by dehydration, and foliar feed it with an all purpose liquid fertilizer on the assumption that the yellowing of the leaves is caused by nutrient deficiency. But the condition of the seedling did not improve.
Any insight on this would be greatly appreciated.