How to Sow and Plant

Marigold may be grown from seed sown early indoors and transplanted outside after frost, or sown directly in the garden after frost, or from potted plants.

Sowing Seed Indoors:

• Sow indoors 4-6 weeks before the last frost using a seed starting kit
• Sow seeds ¼ inch deep in seed starting soil
• Keep the soil moist at 70-75 degrees
• Seedlings emerge in 7-14 days
• As soon as seedlings emerge, provide plenty of light on a sunny windowsill or grow seedlings 3-4 inches beneath fluorescent plant lights turned on 16 hours per day, off for 8 hours at night. Raise the lights as the plants grow taller. Incandescent bulbs will not work for this process because they will get too hot. Most plants require a dark period to grow, do not leave lights on for 24 hours.
• Thin to one seedling per cell when they have two sets of leaves.
• Seedlings do not need much fertilizer, feed when they are 3-4 weeks old using a starter solution (half strength of a complete indoor houseplant food) according to manufacturer’s directions.
• Transplant hardened-off seedlings to the garden after the frost.
• Before planting in the garden, seedling plants need to be “hardened off”. Accustom young plants to outdoor conditions by moving them to a sheltered place outside for a week. Be sure to protect them from wind and hot sun at first. If frost threatens at night, cover or bring containers indoors, then take them out again in the morning.  This hardening off process toughens the plant’s cell structure and reduces transplant shock and scalding.

Sowing Directly in the Garden

• Direct sow seeds in average soil in full sun after all danger of frost. In frost free areas, sow from fall to early spring. In the Deep South, a spot that receives shade during the afternoon helps protect plants from excessive heat. 
• Prepare the bed by turning the soil under to a depth of 8 inches. Level with a rake to remove clumps of grass and stones. 
• Most plants respond well to soils amended with organic matter. Compost is a wonderful form of organic matter with a good balance of nutrients and an ideal pH level, it can be added to your planting area at any time. If compost is not available, top dress the soil after planting with 1-2 inches of organic mulch, which will begin to breakdown into compost. After the growing season, a soil test will indicate what soil amendments are needed for the following season.
• Sow seeds about 6 inches apart and cover with ¼ inch of fine soil.
• Firm soil lightly, water and keep evenly moist.
• Seedlings emerge in 7-14 days.
• Thin plants to stand 9-12 inches when seedlings are 1 inch high.

Planting Potted Plants:

• Select a location in full sun with good rich, moist, well drained organic soil. In the deep South, a spot that receives shade during the afternoon helps protect plants from excessive heat. 
• Prepare the bed by turning the soil under to a depth of 8 inches. Level with a rake to remove clumps of grass and stones. 
• Most plants respond well to soils amended with organic matter. Compost is a wonderful form of organic matter with a good balance of nutrients and an ideal pH level, it can be added to your planting area at any time. If compost is not available, top dress the soil after planting with 1-2 inches of organic mulch, which will begin to breakdown into compost. After the growing season, a soil test will indicate what soil amendments are needed for the following season.
• Dig a hole for each plant large enough to amply accommodate the root ball.
• Set level with the surrounding soil. Fill with soil to the top of the root ball. Press soil down firmly with your hand leaving a slight depression around the plant to hold water.
• Water thoroughly, so that a puddle forms in the saucer you have created. This settles the plants in, drives out air pockets and results in good root-to-soil contact.
• Use the plant tag as a location marker.

How to Grow

• Keep weeds under control during the growing season. Weeds compete with plants for water, space and nutrients, so control them by either cultivating often or use a mulch to prevent their seeds from germinating.
• Mulches also help retain soil moisture and maintain even soil temperatures. For annuals an organic mulch of shredded leaves lends a natural look to the bed and will improve the soil as it breaks down in time. Always keep mulches off a plant’s stems to prevent possible rot.
• Keep plants well-watered during the growing season, especially during dry spells. Watering during dry spells will improve flowering--although it will produce lots of succulent leaves.
• Until plants become established, some protection from extreme winds and direct, hot sunlight may be necessary. Good air movement is also important.
• After new growth appears, a light fertilizer may be applied. Keep granular fertilizers away from the plant crown and foliage to avoid burn injury. Use low rates of a slow release fertilizer, as higher rates may encourage root rots.
• Deadhead marigolds to keep them flowering from late spring until frost.
• Monitor for pests and diseases. Check with your local Cooperative Extension Service for pest controls recommended for your area.
• Remove plants after they are killed by frost in fall to avoid disease issues the following year.

Growing Tips

• Add marigolds to sunny beds, borders and containers. Plant marigolds with both sun-loving annuals and perennials in your garden. Marigolds combine well with lavenders, salvias or sages, cosmos, daylilies, coreopsis, and nasturtium. 
• Marigolds are frequently planted among vegetable crops to prevent pest and disease problems. 
• Many shorter marigold varieties are great for containers.

Common Disease Problems

Alternaria Leaf Spot: Small, round reddish brown spots with white to gray centers form on the upper surface of the leaves. The lesions may encircle the stems and cause wilt. This disease is worse in warm, wet or very humid weather. Burpee Recommends: Avoid getting water on the foliage. Remove infected plant parts and do not work around wet plants. Provide plenty of air circulation. Contact your Cooperative Extension Service for fungicide recommendations.

Aster Yellows: Plants are stunted, develop witch's brooms (excessive growth), petals turn green and become deformed. This virus-like condition is spread by leafhoppers. Burpee Recommends: Remove infected plants and control leafhoppers. Remove weeds in the area which serve as alternate hosts to the disease.

Botrytis: This fungus causes a grey mold on flowers, leaves, stems and buds. It thrives in cool wet weather conditions. White flowers are more susceptible than darker colors.  Burpee Recommends: Remove affected plant parts, avoid watering at night and getting water on the plant when watering. Make sure plants have good air circulation. Contact your Cooperative Extension Service for fungicide recommendations.

Damping Off: This is one of the most common problems when starting plants from seed. The seed emerges and appears healthy; then it suddenly wilts and dies for no obvious reason. Damping off is caused by a fungus that is active when there is abundant moisture and soils and air temperatures are above 68 degrees F. Typically, this indicates that the soil is too wet or contains high amounts of nitrogen fertilizer. Burpee Recommends: Keep seedlings moist but do not overwater; avoid over-fertilizing your seedlings; thin out seedlings to avoid overcrowding; make sure the plants are getting good air circulation; if you plant in containers, thoroughly wash them in soapy water and rinse in a ten per cent bleach solution after use.

Verticillium Wilt: causes a wilting of the leaves and stems on several branches. Leaf margins cup upward, leaves turn yellow and drop off. This will enter through the roots, migrating up the stem and plugging a plant's transport vessels. It is transmitted in the soil. It can also be spread by water and tools. Burpee Recommends: Practice at least a 4 year crop rotation. Remove and burn crop debris.  

Common Pest and Cultural Problems

Aphids: Greenish, red, black or peach colored sucking insects can spread disease as they feed on the undersides of leaves. They leave a sticky residue on foliage that attracts ants. Burpee Recommends: Introduce or attract natural predators into your garden such as lady beetles and wasps who feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap.

Leafhoppers: Leafhoppers cause injury to leaves and stunt growth. They also spread disease. Burpee Recommends: Remove plant debris. Use insecticidal soaps. Consult your Cooperative Extension Service for other insecticide recommendations.

Slugs: These pests leave large holes in the foliage or eat leaves entirely. They leave a slime trail, feed at night and are mostly a problem in damp weather. Burpee Recommends: Hand pick, at night if possible. You can try attracting the slugs to traps either using cornmeal or beer. For a beer trap, dig a hole in the ground and place a large cup or bowl into the hole; use something that has steep sides so that the slugs can’t crawl back out when they’re finished. Fill the bowl about ¾ of the way full with beer, and let it sit overnight. In the morning, the bowl should be full of drowned slugs that can be dumped out for the birds to eat. For a cornmeal trap, put a tablespoon or two of cornmeal in a jar and put it on its side near the plants. Slugs are attracted to the scent but they cannot digest it and it will kill them. You can also try placing a barrier around your plants of diatomaceous earth or even coffee grounds. They cannot crawl over these.

Spider Mites: These tiny spider-like pests are about the size of a grain of pepper. They may be red, black, brown or yellow. They suck on the plant juices removing chlorophyll and injecting toxins which cause white dots on the foliage. There is often webbing visible on the plant. They cause the foliage to turn yellow and become dry and stippled. They multiply quickly and thrive in dry conditions. Burpee Recommends: Spider mites may be controlled with a forceful spray every other day. Try hot pepper wax or insecticidal soap. Check with your Cooperative Extension Service for miticide recommendations.

Thrips: Thrips are tiny needle-thin insects that are black or straw colored. They suck the juices of plants and attack flower petals, leaves and stems. The plant will have a stippling, discolored flecking or silvering of the leaf surface. Thrips can spread many diseases from plant to plant. Burpee Recommends: Many thrips may be repelled by sheets of aluminum foil spread between rows of plants. Remove weeds from the bed and remove debris from the bed after frost. Check with your Cooperative Extension Service for pest controls. 

FAQ

Can I use marigolds as cut flowers? Yes, for fresh bouquets, cut newly opened blooms early in the morning and immediately set the stems in a jar of warm water. Later, strip the stems of lower leaves that might foul the water and arrange the flowers in a vase with fresh water. Marigolds will last up to a week, even longer if you add some floral preservative to the vase water. Marigolds are also great for dried arrangements and floral crafts. Cut perfect blossoms at their peak; remove foliage from the stems; and hang upside down in a warm, dry place such as an attic until dry. The flowers will shrink a bit, but their color will remain strong. Insert wire into the marigold stems if needed for support in an arrangement.

My marigolds are tall, skinny with small flowers, what happened? Usually this is a result of overcrowding. Make sure to space or thin plants at the recommended spacing.

Do marigolds attract beneficial insects to my garden? Yes, they attract pollinators such as bees and butterflies, as well as other beneficial insects.

Do marigolds make good companion plants? Yes, they are good companion for beans and cucumbers because they can repel beetles. They can also repel nematodes in the garden.

Are marigolds edible? Yes, the flowers of smaller flowered marigolds make a lovely garnish on salads.