First grow from seed

Growing in the same condition, two plants do well but two others are struggling. I would rule out more fertilizers and snake oils. Could be phenotype. Plants grow from seeds are usually not equal. I prefer to first run large batch from seed. Then, I would choose a good one to make mother of clone to continue until I get to bored. Could be some bad things in the soil. Any things goes from strange bacteria, strange fungus, root knotting tiny red worms. For worm/bugs/nematode: I mix abamectin 3 ml per liters. Pour that in place of water on all plants. Read safty and usage data. If its fungus, I mix trichorderma to the soil. If it is bacteria, soil will smell rotton. Soil need better drainage or less watering. I use two o[ptions: 1) Mix new soil with better drainaige and add micorhizae. Fungus competes with bacteria. Micorhizae is a family of benefical fungus. Small plants will be in ICU. And will take a month or two to catch up. This is the hardest and most popular option. 2) Nobody belive the second option. I grow pig weeed as companion plant in cannabis pot. Pig weed sucks up excess salt fertilizer. Spread root to take up free space. Water drains much better. Pig weed root releasess beneficial plant growth stimulator. Pig weed root nurses benefical microbes. It is counter intuitive to intentionally grow plants that compete with cannabis on fertilizers. However, I get good result easily when growing pig weed with cannabis. Another thing, plants are growing in nature in communities with big variety of species. There are interactions among plants. With right mix, the plants can havy symbiotic relationship in both growing and defending each other.