Yes, dill grows well alongside tomatoes and can help your garden
Dill and tomatoes are companion plants—they grow in the same space without competing for resources, and dill actually improves conditions for tomatoes. Dill attracts beneficial insects like parasitic wasps and hoverflies, which prey on common tomato pests such as hornworms and aphids. The two plants have different root depths and nutrient needs, so they won't fight underground. You can plant dill seeds directly in the soil near tomato plants or start them indoors and transplant seedlings once they're a few inches tall.
The main thing to watch is dill's height and spread. Mature dill plants reach 2 to 3 feet tall and can shade smaller tomato seedlings if planted too close. Space dill at least 12 inches away from tomato stems, and plant it on the north or east side of tomatoes so it doesn't block afternoon sun. Dill also self-seeds readily—once it flowers and drops seeds, new plants will sprout the following season, which is helpful if you want continuous dill but can become a nuisance if you don't.
Key Takeaways
- Dill attracts parasitic wasps and hoverflies that eat tomato pests like hornworms and aphids, reducing the need for pesticides.
- Plant dill at least 12 inches away from tomato stems and position it where it won't shade the tomato plant during peak sun hours.
- Dill and tomatoes have different root systems and nutrient demands, so they do not compete for water or soil nutrients.
- Dill flowers and self-seeds, so you can harvest leaves early or let it mature and collect seeds for next season's planting.
How dill protects tomatoes from common pests
Dill flowers attract parasitic wasps, tiny insects that lay eggs inside tomato hornworms and other soft-bodied pests. When the wasp eggs hatch, the larvae consume the pest from the inside, killing it before it can damage your tomatoes. Hoverflies, which look like small bees, also visit dill flowers and lay eggs near aphid colonies. The hoverfly larvae then feed on the aphids. Neither parasitic wasps nor hoverflies sting or bite humans, and they leave once their food source is gone.
This natural pest control works best when dill is allowed to flower. If you harvest dill leaves for cooking before the plant flowers, you'll still get the benefit of the foliage, but the pest-control insects won't arrive until later in the season when dill blooms. Many gardeners plant dill in two batches—one early for leaf harvesting and one later specifically to flower and attract beneficial insects.
Spacing and positioning dill near tomatoes
Dill grows tall and can shade nearby plants if positioned incorrectly. Plant dill seedlings or seeds at least 12 inches away from the tomato stem, measured from the center of the tomato plant outward. If your tomato plant is staked or caged, measure from the edge of the cage or stake, not the stem itself.
Position dill on the north or east side of tomatoes so the dill plant grows in the direction away from the tomato's main sun exposure. Tomatoes need 6 to 8 hours of direct sunlight daily, and dill's feathery foliage can reduce that if it's planted to the south or west. In very hot climates, some afternoon shade from dill can actually benefit tomatoes by keeping soil cooler, but this works only if the dill is positioned to filter late-day sun, not block midday light.
When to plant dill for best results with tomatoes
Plant dill at the same time you plant tomato seedlings or just after, once soil has warmed to at least 60°F. Dill seeds germinate in 7 to 10 days in warm soil. If you start dill indoors, sow seeds 4 to 6 weeks before your last spring frost, then transplant seedlings outdoors after the frost date has passed and soil is workable.
For continuous dill harvest, sow new seeds every 2 to 3 weeks through early summer. This staggered planting means you'll have young dill plants for leaf harvesting and mature plants flowering to attract beneficial insects at different times. Stop planting dill about 8 weeks before your first fall frost so plants have time to mature and set seed before cold weather arrives.
Harvesting dill without harming the plant
Pinch off dill leaves from the top of the plant once it reaches 6 inches tall. This encourages bushier growth and delays flowering, giving you more harvestable foliage. Pinch just below a leaf node—the spot where leaves branch off the stem—and remove no more than one-third of the plant at a time.
If you want dill to flower and attract beneficial insects, stop harvesting leaves when the plant reaches about 18 inches tall and begins to form flower buds. Let the flowers open and mature into seed heads. Once seed heads turn brown and dry, you can collect them for next season or let them drop naturally to self-seed in your garden bed.
Dill varieties that work best in tomato gardens
'Bouquet' and 'Dukat' are compact dill varieties that stay under 2 feet tall, making them easier to position near tomatoes without shading. 'Fernleaf' is a dwarf variety reaching only 12 to 18 inches, ideal for small spaces or containers placed near tomato plants. Standard varieties like 'Mammoth' grow 3 feet or taller and work well if you have room to space them farther from tomatoes.
For leaf production, 'Dukat' and 'Bouquet' hold their flavor longer before flowering, so you get more harvests before the plant shifts energy to seed production. If your main goal is attracting beneficial insects, any variety will work once it flowers—the insect-attracting compounds are the same across all dill types.
Soil and water needs when growing dill with tomatoes
Dill and tomatoes have different watering schedules, which is one reason they pair well. Tomatoes prefer soil that dries slightly between waterings, while dill tolerates both moist and drier conditions. Water both plants when the top inch of soil feels dry to the touch, and you'll meet both plants' needs without adjusting your routine.
Dill doesn't need rich soil and actually grows better in moderate fertility. If your tomato bed has been amended with compost or fertilizer for tomatoes, dill will thrive in that same soil without additional feeding. In fact, over-fertilizing dill encourages leafy growth at the expense of flowering, which reduces the number of beneficial insects that visit. Use the same balanced fertilizer schedule for both plants, or skip extra feeding for dill entirely.
Frequently Asked Questions
Will dill take nutrients away from my tomatoes?
No. Dill roots grow shallower than tomato roots, and dill uses less nitrogen than tomatoes. The two plants occupy different soil layers and have different nutrient demands, so they don't compete. Dill may even improve soil structure as it decomposes at the end of the season.
Can I plant dill in a container next to a tomato pot?
Yes. Dill grows well in containers at least 6 inches deep and 6 inches wide. Place the dill container where it won't shade the tomato pot during peak sun hours. Container dill dries out faster than garden dill, so check soil moisture more often and water when the top half-inch feels dry.
What if dill self-seeds and spreads everywhere?
Dill seedlings are straightforward to pull out by hand when they're small. If you want to prevent self-seeding, cut off flower heads before seeds mature and dry. Alternatively, let dill flower in one area of the garden and pull seedlings from other spots as they appear—this gives you control over where dill grows each season.
Does dill attract any pests that harm tomatoes?
Dill occasionally attracts spider mites and aphids to itself, but these pests prefer dill over tomatoes and rarely move to nearby tomato plants. The beneficial insects dill attracts actually reduce the overall pest population in your garden, so any pests on dill are usually controlled by natural predators.
Can I plant dill in fall for spring tomatoes?
Dill is a cool-season plant and grows best in spring and fall. If you plant dill in fall, it will mature and flower before winter in most climates, then die back. Plant new dill in spring when you plant tomatoes for the best companion planting effect during the tomato growing season.