How To Grow Marigolds From Seed Outdoors. Now lightly cover with some more compost. In this case, once the seeds germinate, transplant them outdoors after the last frost.
If you do nothing, they will all grow together and the strongest will take over and kill the tinier ones. Marigolds can be grown easily as companion plants in pots and containers and in the vegetable garden to attract pollinators and natural pest predators and to kill nematodes, repel aphids and camouflage carrots. Marigolds can be sown straight in the ground where they are going to flower, so make sure the soil you sow is weed free by using a trowel to remove the weeds.
In general, you can plant smaller.
They also don't need a soil that is particularly rich in organic matter and seem to grow better in a leaner soil. This variety will grow to reach about eighteen inches in height and sheds water from its flowerheads more easily than other african marigolds. Marigolds can also be started early indoors under grow lights for transplanting outdoors about six to eight weeks before the last frost date. It is important to place your marigolds outdoors in full sun.