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Marigolds and Tomatoes: Quintessential Companions
When you think of companion planting, one of the most common pairings that comes to mind is marigolds and tomatoes. But just what makes these two such a good match?
While there’s plenty of gardening advice out there suggesting why they might work well together, only a few studies have been done that can confirm their benefits. As such, you may have to try the pairing for yourself to see if it works for your garden. Don’t hesitate to play around with planting time, placement, and marigold variety to see what works best. After, all every garden has its own set of unique circumstances!
Marigolds Repel Tomato Pests
One of the most commonly touted benefits of planting marigolds and tomatoes together is that marigolds will keep harmful pests away. Marigolds are known to prevent root-knot nematodes and whiteflies, and there’s anecdotal evidence of their smell keeping other bad bugs, like the tomato hornworm and aphid, at bay. Some have suggested rabbits, deer, and other large tomato-eaters are also deterred by the smell.
Root-knot nematodes are microscopic worms in the ground. They attach themselves to the roots of plants and cause them to swell, causing stunted growth and death to the host plant. Marigold roots release a chemical that can kill nematode eggs. For the best protection, plant marigolds a week or two ahead of the tomatoes. You can also try planting your tomatoes where marigolds were growing last year.
While most companion planting is based on what gardeners themselves observe, scientists conducted a study recently that showed that the limonene in marigolds (also found in citrus peels) can prevent a buildup of whiteflies on tomatoes. It only works when they’re planted together from the start, though – if whiteflies have already infested your crop, adding marigolds later won’t help much.
Snail and Slug Trap Crop
While not quite the same as repelling, marigolds can act as a trap crop for snails and slugs when placed around the perimeter. Marigold leaves and stems are a tasty treat for the slimy creatures, and they aren’t as likely to eat your tomatoes when the marigolds are around.
Marigolds Attract Pollinators and Pest Eaters
In addition to preventing bad bugs, marigolds attract beneficial pollinators, like bees and butterflies, which will help pollinate your tomatoes (and the rest of the garden, too).
Ladybugs, which are also attracted to marigolds, will additionally help by eating any stray aphids.
Marigolds often draw in parasitic wasps. The name might not sound like something you want to attract to the garden, but the wasp larvae are actually parasitic to tomato hornworms. So in this case, the parasitism will benefit you!
Similar Growth Needs
Both marigolds and tomatoes require the same growing conditions – they like full sun and well-draining soil. They both enjoy regular watering, though neither appreciates being left soggy for too long.
Pretty much any tomato will pair well with one of the following marigold types, but you can also compare your seed packets during selection so that you pick one that will best match your tomatoes’ needs.
Types of Marigolds to Plant with Tomatoes
The three most common types of marigolds to plant with tomatoes are African, French, and signet. All will attract pollinators and repel certain pests, but which one you use will depend on your garden layout and your preferences.
African Marigolds – Most African marigolds are large – from 1-3 feet tall – and have blooms 4-5 inches wide. They come in the traditional colors, usually orange, red, and yellow. African marigolds may deter deer in particular.
French Marigolds – French marigolds are smaller, with only 2-3 inch blooms at a height of around a foot. This variety is ideal for nematode protection. They come in many colors – including the beautiful strawberry blonde varieties!
Signet Marigolds – Signet marigolds are the smallest variety, with petite flowers and a slightly bushier appearance. They’re perfect for attracting pollinators.
How to Plant Marigolds and Tomatoes Together
Planting marigolds and tomatoes together is fairly easy if you keep a few tips in mind.
Plant marigolds a week or two before the tomatoes to help avoid nematode and whitefly buildup. You can start them several weeks ahead from seed or get them from a greenhouse, but either way transplanting a marigold into the garden will increase your odds of controlling pests. Leave 18-24 inches of space for your tomatoes when planning and planting marigolds.
Once you’ve added the tomatoes into the garden, water them both as needed. Allow the soil to dry out between waterings.
Marigolds appreciate deadheading, and they will bloom more profusely if their dead blooms are clipped regularly. The exception is signet marigolds, which normally bloom happily without any major care.
At the end of the season, work your dead marigolds back into the soil for potentially continued nematode protection.