Yes, dill and tomatoes grow well together, but timing matters
Dill and tomatoes are genuine companion plants—they support each other's growth and can share the same garden bed without competing for resources. Dill attracts beneficial insects like parasitic wasps and hoverflies that prey on common tomato pests such as hornworms and aphids. The herb also has a shallow root system that doesn't interfere with tomato roots, which grow deeper into the soil. In return, tomatoes provide afternoon shade that keeps dill from bolting too quickly in hot weather.
The catch is that dill grows fast and can mature before your tomatoes are ready to harvest. If you plant them at the same time, dill will flower and set seed while tomatoes are still ripening, which means you'll need to decide whether to pull the dill early or let it complete its cycle. Most gardeners plant dill in succession—a few seeds every two to three weeks—so they always have young plants available while tomatoes are still producing.
Key Takeaways
- Dill's shallow roots won't compete with tomato roots, and the herb attracts predatory insects that eat tomato pests like hornworms and aphids.
- Plant dill seeds every two to three weeks rather than all at once, so you have young plants throughout the tomato season instead of one mature crop that bolts.
- Dill flowers are edible and attract pollinators, but once it sets seed it stops producing leaves, so harvest or replant before that stage if you want fresh dill all season.
- Space dill plants 6 to 12 inches apart around the base of tomato plants or between rows, keeping them at least 6 inches away from the tomato stem itself.
How dill protects tomatoes from pests
Dill flowers attract parasitic wasps, which lay their eggs inside tomato hornworm larvae and aphids. When the wasp eggs hatch, the larvae consume the pest from the inside, killing it before it can damage your tomatoes. Hoverflies, also called flower flies, are another beneficial insect drawn to dill blooms. Adult hoverflies feed on nectar and pollen, but their larvae are voracious aphid hunters—a single larva can eat 50 to 60 aphids before it pupates.
This pest control is most effective when dill is flowering, which is why succession planting works better than planting all your dill at once. If you plant a large batch of dill seeds on the same day as your tomatoes, the dill will flower for a few weeks and then finish its life cycle, leaving your tomatoes unprotected during the rest of the growing season. By planting dill every few weeks, you may support that some plants are always in bloom and attracting beneficial insects.
Planting dill and tomatoes together: spacing and timing
Plant dill seeds directly into the soil around tomato plants after the soil has warmed to at least 60°F. Sow seeds about one-quarter inch deep and keep the soil moist until seedlings emerge, which usually takes 7 to 10 days. Once dill seedlings are 2 to 3 inches tall, thin them so plants are spaced 6 to 12 inches apart. The exact spacing depends on the dill variety—dwarf varieties like 'Fernleaf' can be closer together, while full-size dill needs more room.
Keep dill at least 6 inches away from the tomato stem to avoid shading the lower leaves or creating humidity that encourages fungal disease. Plant dill between tomato rows or around the perimeter of your tomato bed rather than directly against the plant. If you're using stakes or cages to support tomatoes, plant dill on the side that gets afternoon shade from the support structure—this slows bolting and extends the harvest window.
For succession planting, mark your calendar to sow new dill seeds every 2 to 3 weeks starting when you plant tomatoes. Stop planting dill about 6 to 8 weeks before your first expected frost, since dill won't have time to mature and flower before cold weather arrives. In warm climates where frost doesn't occur, you can plant dill year-round as long as temperatures stay above 50°F.
When dill and tomatoes compete for space
Dill bolts—meaning it flowers and stops producing leaves—when temperatures consistently exceed 75°F or when the plant reaches maturity, whichever comes first. Once dill flowers, the leaves become thin and bitter, and the plant's energy goes into seed production rather than foliage. In hot climates, this can happen in as little as 4 to 6 weeks from planting. In cooler regions, dill may produce leaves for 8 to 10 weeks before flowering.
If you want fresh dill leaves throughout the tomato season, harvest the plant before it flowers by pinching off the top 2 to 3 inches of growth. This delays flowering by a week or two but eventually the plant will bolt anyway. That's why succession planting is the most reliable strategy—you pull out the bolted dill and replace it with a younger plant that still has weeks of leaf production ahead.
If you let dill flower intentionally, the blooms are edible and attractive to pollinators, which can improve tomato fruit set. You can also collect dill seeds for next year's garden or for cooking. Just be aware that once you decide to let dill flower, you're choosing flowers and seeds over fresh leaves.
Other herbs that pair well with tomatoes
Basil is the most famous tomato companion and works for similar reasons—it repels some pests and doesn't compete for root space. Unlike dill, basil thrives in the same warm conditions as tomatoes and won't bolt as quickly, making it easier to maintain throughout the season. Parsley, chives, and cilantro also grow well alongside tomatoes, though cilantro bolts quickly in heat just like dill does.
Marigolds are often planted near tomatoes because they attract beneficial insects and may deter some soil-dwelling pests, though scientific evidence for this is mixed. Nasturtiums act as a trap crop—pests prefer them to tomatoes, so planting nasturtiums nearby can draw insects away from your main crop. Borage flowers attract pollinators and beneficial insects while its deep taproot brings up nutrients from lower soil layers without competing with tomato roots.
Common mistakes when planting dill with tomatoes
The biggest mistake is planting dill too close to the tomato stem. Dill grows tall and bushy, and crowding it against tomatoes creates shade and traps humidity around the lower tomato leaves, which encourages early blight and other fungal diseases. Always leave at least 6 inches of clear space between the dill plant and the tomato stem, and thin seedlings aggressively—it's better to have fewer, well-spaced plants than a dense cluster.
Another common error is expecting one planting of dill to last the entire tomato season. Dill matures and flowers whether you want it to or not, so plan for succession planting from the start. If you wait until your first dill plants bolt to plant more, you'll have a gap of several weeks with no dill flowers and fewer beneficial insects visiting your tomato bed.
Overwatering dill is also a problem. Dill prefers soil that is moist but not soggy, and it's more drought-tolerant than tomatoes. If you water heavily for tomatoes, dill may develop root rot. Water at the soil level rather than overhead to keep dill foliage dry, and let the top inch of soil dry out between waterings.
Harvesting dill while tomatoes are still growing
Begin harvesting dill leaves once the plant is 6 to 8 inches tall, usually 3 to 4 weeks after planting. Pinch off the top 2 to 3 inches of growth, which encourages the plant to branch and produce more leaves. Harvest regularly—every few days if possible—to delay flowering and keep the plant producing tender new growth. The more you harvest, the longer the plant will stay in the leaf-production stage.
Dill leaves are best used fresh, though they can be dried or frozen for later use. Dry dill by hanging small bunches upside down in a warm, airy location out of direct sunlight, or strip the leaves and dry them on a screen. Frozen dill retains flavor better than dried dill for most cooking purposes—chop fresh leaves and freeze them in ice cube trays with a little water, then pop out cubes as needed.
Frequently Asked Questions
Can I plant dill and tomatoes in the same pot?
Yes, but only in a large container at least 18 inches deep and 24 inches wide. Plant one tomato in the center and dill seedlings around the perimeter, spaced at least 6 inches from the tomato stem. Water carefully since both plants will share the same soil moisture, and dill may bolt faster in a container due to heat buildup. This works best in cool climates where temperatures stay below 75°F.
Does dill attract bad insects to tomatoes?
Dill attracts beneficial insects that eat tomato pests, not pests themselves. Some insects like spider mites may visit dill flowers, but they're not drawn there specifically and won't cause significant damage. The beneficial insects that dill attracts—parasitic wasps and hoverflies—far outweigh any minor pest pressure.
What if my dill flowers before my tomatoes are ready to harvest?
Pull out the flowering dill and plant new dill seeds when ready. The old plant has finished its useful life for leaf production, and leaving it in the ground wastes space. Plant a fresh batch of dill seeds, which will germinate and grow while your tomatoes are ripening, ensuring you have beneficial insects around during the final weeks of the season.
Can I use dill flowers in cooking while tomatoes are still on the vine?
Yes, dill flowers are edible and add a mild, slightly sweet flavor to salads, pickles, and fish dishes. Harvesting flowers doesn't harm the plant's ability to produce more blooms, so you can use them while still benefiting from the pest-control insects they attract. Just be aware that once dill is flowering heavily, it's producing fewer leaves.
Is dill safe to plant near tomatoes if I use pesticides?
Pesticides kill beneficial insects along with pests, which defeats the purpose of planting dill. If you use any pesticide on tomatoes, avoid spraying near dill plants and wait at least a week before planting new dill. Organic insecticides like neem oil or spinosad are less harmful to beneficial insects than synthetic pesticides, but they still kill some helpful bugs.