Marigolds are one of the most popular annual plants grown in landscapes, gardens and containers. Marigold flowers are easy to grow, come in a wide variety of sizes and bright yellow, orange and red color combinations, and, most important to gardeners, they are, what is called, companion plants for many vegetable plants. Planting marigolds among your vegetables helps keep many damaging pests away.
Start your marigold seeds inside six to eight weeks before the last frost in your area. Marigold plants will flower 45 to 50 days after planting. You can also plant directly into your garden or landscape after the last frost by following the directions for planting seedlings, but you will need to thin the seedlings.
Plant your marigold seeds in good potting soil that is in flats or containers. Your seeds should be planted 1/4 inch deep.
Add water to the potting soil that you planted your marigold seeds in to maintain a moist environment for the seeds to germinate and grow. Monitor the soil moisture so it does not dry out or become soggy.
Locate your planted marigold seeds where they can receive strong light and are warm. Your seeds will germinate faster (three to five days) in warm soil.
Transplant your seedlings into your garden or landscape after the last frost and when the seedlings have developed their second or third leaf set.
Select only healthy seedlings or plants to grow that do not show signs of wilt or disease. It is also better, if you are purchasing your plants, to select plants that either do not have buds or flowers because you want your marigold plants to use their energy to develop strong roots before they use up their energy to produce flowers.
Use a shovel or trowel to dig up 8 to 10 inches of soil where you intend to plant your marigold seedlings. As you dig up the soil, break up any large clods of soil. By digging up your soil you are aerating it, which your marigold plants will benefit from.
Work compost or organic material, such as old leaves and vegetation, into the soil you have dug up. Marigold plants prefer rich, well-draining soil, so the addition of compost or organic material will feed your marigold plants.
Plant your marigold plants so they receive full sun and are 8 to 18 inches apart, depending on the variety you are planting. Small varieties can be spaced closer than varieties that grow taller and broader.
Water your marigolds to keep the soil moist, usually once or twice a week, more frequently during very hot spells. Add mulch around your marigold plants to keep the moisture in the soil and weeds away.
Fertilize your marigold plants every four to six weeks with a general all-purpose fertilizer for flowers. Or, work in compost around your marigold plants once a month.