Marigolds flower from June to the first frost and put up with both drought and neglect. They are sown in March, germinate in a week and cost almost nothing. Three species are sold, they look different and they are used for different things, and that is also where most guides stop.
Three species, three uses
| Species | Common name | Height | Spacing | Best for |
|---|---|---|---|---|
| Tagetes patula | French marigold | 20 to 30 cm | 20 cm | Edging, pots, soil improvement |
| Tagetes erecta | African marigold | 40 to 90 cm | 30 to 40 cm | Border and cutting |
| Tagetes tenuifolia | Signet marigold | 20 to 30 cm | 20 cm | Edible flowers |
Our variety Vanilla F1 is an African marigold with double creamy white flowers instead of the usual orange. The flowers are edible and often used to decorate baking.
Sowing marigolds
Sow indoors 6 to 8 weeks before planting out, so in March or April.
Cover the seed with 0.5 cm of compost. The seeds are long and thin and are easiest sown one by one.
Hold 18 to 22 degrees. Germination takes 5 to 10 days and is even.
Prick out at the first pair of true leaves into individual pots.
Harden off and plant out at the end of May, once the frost risk has passed.
Sowing direct in place works from late May but flowering then starts in July.
Position, soil and feeding
Full sun and free-draining soil. Marigolds want lean soil: in rich, freshly manured ground you get a large green bush with few flowers. Give no nitrogen feed during the season. If you need to feed at all, use a high-potassium feed every third week from budding.
Once established they take drought, but in a pot they need water every day in July.
Nematodes: what is actually true
The claim that marigolds suppress nematodes in the soil is repeated everywhere, usually without the conditions. Here they are.
The species matters. The effect is documented above all for the French marigold (Tagetes patula). Its roots release a compound called alpha-terthienyl.
It takes a stand, not a few plants. Three marigolds between the tomatoes do nothing measurable. It is about growing the area densely covered.
Time is decisive. Reckon on three to four months on the same ground to bring the nematode pressure down.
It works where the roots are. The effect sits in the soil around the roots, not in the air around the leaves.
In practice that means marigolds work as a green manure on a bed you want to rest for a year, not as a companion between the rows. As a companion they have a different value: they pull in pollinators, and deer and hares avoid the scent.
Edible flowers
Marigold petals are edible and taste anything from mild citrus to spicy depending on the species.
Signet marigold (T. tenuifolia) has a clear citrus flavour and suits a salad.
African marigolds like Vanilla are used mostly to decorate baking and dishes.
Dried petals can be stirred into oven-roasted granola or into tea.
Pick in the middle of the day when the flowers are dry, and use only the petals. The green base of the flower head is bitter.
Deadhead properly
Removing spent flowers gives more blooms, but do not just pinch the head off. Cut the stem back to the nearest pair of leaves. The plant then breaks two new shoots instead of leaving a bare stub.
Do it once a week from July and the plant flowers until frost.
Slugs
Marigolds attract slugs, especially small plants in June. Do not plant out too early and put protection out for the first weeks. Some growers use them deliberately as a trap crop along the edge of the vegetable garden for exactly that reason.
Saving your own seed
Let a few flower heads dry on the plant until they are brown and papery. Pull out the long black and white seeds and store them dry and dark.
An open-pollinated variety gives offspring that resemble the parent. An F1 hybrid like Vanilla does not: the seed germinates but the flowers scatter in colour and form. If you want the same result next year, buy fresh seed.
More annuals sown the same way are among our flower seeds, and if the marigolds suit your vegetable garden you can read on in growing edibles.
Author: Emma Vogiatzi
Fact checked by Erik Hoekstra
Last updated 2026-08-31