Companion Planting: The best neighbours for Tomatoes & Chillis

Tomatoes and chillis are cornerstones of the homestead garden — productive, rewarding, and surprisingly social. The right neighbors can help them thrive: attracting pollinators, keeping pests in check, improving soil, and making the most of limited space. Below are the companions we reach for again and again, why they work, and practical ways to plant them so you get healthier, more abundant crops.

Why companion planting matters

Companion planting is about ecological relationships. Some plants attract beneficial insects that eat pests. Others mask the scent of your crops or act as trap crops, keeping pests away from your prized fruit. Certain herbs and flowers also improve soil structure, add organic matter, or make maintenance easier by creating a healthier microclimate. When you pick companions with compatible water and light needs, you end up with a more resilient patch.

Top companion plants and what they do

Basil

Why: Attracts pollinators, may deter some flying pests, and keeps a similar moisture and fertility profile to tomatoes and chillis.

How to use: Plant basil between tomato plants or at the base of chilli plants. Harvest frequently to encourage bushy growth. In containers, a pot of basil next to chilli plants helps maximize space.

Borage

Why: Excellent at attracting bees and other pollinators; its flowers bring beneficial insects. Borage is also thought to deter tomato hornworms, and its leaves can be cut and used as a mineral-rich mulch.

How to use: Interplant borage among tomatoes or chillis; it grows tall enough to sit between rows without shading too much. Cut back if it gets too large.

Marigolds (especially French marigolds, Tagetes patula)

Why: Known for deterring certain soil nematodes and attracting predatory insects. Planting a generous border of marigolds can reduce pest pressure around Solanaceae.

How to use: Plant marigolds along bed edges or in interspersed pockets. Use them widely rather than a single plant — their protective effect is cumulative.

Nasturtiums

Why: Act as trap crops for aphids, whiteflies, and some beetles; their flowers and leaves are edible and attractive to pollinators.

How to use: Let nasturtiums trail at the edge of your bed or grow them in pots nearby. Check them regularly and remove heavy aphid infestations to keep pests off your tomatoes and chillis.

Alliums (chives, garlic, onions)

Why: Their strong scent can deter aphids and other pests, and their flowers attract beneficial predators like hoverflies and parasitic wasps.

How to use: Plant chives at the bases of tomato plants, and garlic or onions around the perimeter. Be mindful of spacing so all plants get enough light.

Parsley, cilantro, and dill (herb allies)

Why: These herbs attract beneficial insects — parasitic wasps, lacewing,s and predatory flies — that help control caterpillars and aphids.

How to use: Scatter them through and alongside beds. Allow a few to bolt for flowers that attract beneficial insects, but pull bolted herbs if they begin to shade or crowd your vegetables.

Legumes (bush beans, fava beans)

Why: Nitrogen-fixers that can improve soil fertility for heavy feeders like tomatoes and chillis. Beans can also be a short-term canopy that reduces weeds early in the season.

How to use: Plant bush beans in separate rows or alternating sections, rather than directly next to sprawling indeterminate tomatoes, to reduce competition and disease spread. In small beds, use beans in rotation or in nearby beds.

Practical layout ideas

4x4 or single raised bed: Plant 2–3 tomato plants spaced for their variety (bushy determinate or taller indeterminate with stakes). Interplant basil and parsley at the base, tuck borage or marigolds in the corners, and let nasturtiums trail over the edge.

Row planting: Set tomatoes or chillis in the center, marigolds at both edges, and chives or garlic staggered along the row. Use legumes in a short adjacent row to return nitrogen to the soil later in the season.

Containers: Keep chillis and tomatoes in large pots; companion herbs like basil, chives, or a small marigold pot can live in the same container if it’s big enough, or sit in neighboring pots to prevent root crowding.

Watering, fertility, and disease notes

Match companions by water needs: Tomatoes and chillis like steady moisture. Select companions with similar needs (such as basil, borage, and chives) rather than dry-loving plants that will compete.

Keep airflow: Dense interplanting can increase humidity and disease. Give tomatoes and chillis enough space and prune lower foliage to improve air circulation.

Mulch and consistent watering: Use organic mulch to stabilise soil temperature and suppress weeds. Water at the base to avoid wet foliage and reduce the risk of fungal diseases.

Rotate Solanaceae: Tomatoes, chillis, peppers, and potatoes share many pests and diseases. Rotate them out of the same bed for 2–3 years whenever possible.

Companions to avoid

Potatoes: Share many diseases with tomatoes and chillis (late blight, blight pathogens) — avoid planting them together or in immediate succession.

Fennel: Generally inhibits nearby plants and attracts pests that can be problematic; keep fennel well away from your vegetable beds.

Crowding with heavy feeders or tall, dense plants: Avoid planting sun-hogging crops that will deprive tomatoes and chillis of light or create overly humid conditions.

Maintenance tips that make companions pay off

Monitor and act: Check trap crops, such as nasturtiums and marigolds, for concentrated pest populations and remove heavily infested growth.

Encourage beneficials: Let some plants flower (such as parsley, dill, and borage) so that predators and pollinators stick around.

Harvest herbs often: Regular cutting of basil, chives, and parsley keeps them vigorous and reduces shading of your main crop.

Putting it into practice

A simple starter plan: Plant three indeterminate tomato plants spaced 60–90 cm apart (24–36 in). Put basil between plants and along the front; add three or four marigolds around the bed edges; tuck a couple of borage plants in low-traffic spots; let nasturtiums trail over the curb. For a chilli container, plant one chilli in a 10–15 L (2.5–4 gallon) pot with a basil plant at its base and a chive cluster in a nearby pot.

Companion planting is not a silver bullet, but done thoughtfully, it multiplies the strengths of individual plants. At GreenHearth Homestead, we select companions that share our needs, attract beneficial insects, and reduce pest and soil problems, allowing our tomatoes and chillis to produce more and require less intervention. Try one or two combinations this season and notice how the garden’s balance shifts — small changes yield lasting rewards. If you’d like, please tell me your bed size and plant varieties, and I’ll sketch a companion layout for you to use.