May is a vibrant month in the garden—the soil is warming, the days are longer, and it is prime time to get your hands in the dirt. Whether you’re growing vegetables, herbs, or flowers, planting the right crops side by side can make a big difference in your garden’s health and productivity. This is where companion planting comes in.

Companion planting is the art of pairing plants that benefit one another—through pest control, soil improvement, shade, support, or pollination. In contrast, some plants can compete or even hinder each other’s growth. By understanding which plants thrive together, you can boost yields, reduce disease, and make your garden more self-sustaining.

This guide will help you plan and plant a successful garden this May, focusing on the best companion planting combinations for a thriving, harmonious space.

What Is Companion Planting?

Companion planting is a time-tested gardening technique that uses the natural properties of plants to support one another. It can involve:

• Pest deterrence: Some plants repel pests that bother their neighbors.
• Pollinator attraction: Flowers can draw in bees and butterflies to help nearby crops.
• Soil improvement: Certain plants fix nitrogen or help break up compacted soil.
• Physical support: Tall plants provide natural stakes or shade for smaller ones.
• Flavor enhancement: Some herbs improve the flavor of nearby fruits or veggies.

Companion Planting Combos for May

As you’re planting your warm-season crops in May, here are some of the best plant partnerships to try in your garden:

1. Tomatoes + Basil + Marigolds

• Why they work: Basil helps repel tomato hornworms and improves tomato flavor. Marigolds deter nematodes and aphids while attracting pollinators.
• How to plant: Surround tomato plants with basil and interplant marigolds throughout the tomato bed.

2. Carrots + Onions + Lettuce

• Why they work: Onions help deter carrot flies. Lettuce grows quickly and provides a light canopy for young carrots.
• How to plant: Plant rows of carrots and onions alternately, with lettuce tucked in between as a living mulch.

3. Cucumbers + Nasturtiums + Dill

• Why they work: Nasturtiums attract aphids away from cucumbers and draw in pollinators. Dill deters cucumber beetles and supports beneficial insects.
• How to plant: Allow nasturtiums to sprawl near cucumbers and tuck dill into corners or pots nearby.

4. Beans + Corn + Squash (The Three Sisters)

• Why they work: A classic Native American trio—beans fix nitrogen, corn provides a natural trellis, and squash shades the ground to suppress weeds and retain moisture.
• How to plant: Form a small mound, plant corn in the center, beans around it, and squash around the outer edge.

5. Peppers + Oregano + Onions

• Why they work: Oregano deters pests and adds ground cover, while onions repel aphids and other insects. This combo supports peppers as they grow and fruit.
• How to plant: Plant peppers with onions nearby and low-growing oregano between rows.

6. Zucchini + Borage + Nasturtiums

• Why they work: Borage attracts bees and improves zucchini growth. Nasturtiums act as a pest trap and bloom beautifully.
• How to plant: Borage can grow alongside or behind zucchini, with nasturtiums trailing nearby.

7. Beets + Garlic + Lettuce

• Why they work: Garlic keeps pests away from beets. Lettuce acts as a living mulch, retaining moisture around slow-growing beets.
• How to plant: Plant garlic sparsely between beet rows and interplant lettuce as a quick-growing ground cover.

Plants That Don’t Get Along (Beware These Combos)

While some plants are best friends, others are not. Avoid these bad pairings:

• Tomatoes + Corn: Compete for the same nutrients and attract similar pests (like the corn earworm).
• Beans + Onions: Onions can stunt bean growth.
• Carrots + Dill: Dill can hinder carrot development as it matures.
• Cucumbers + Potatoes: Both are heavy feeders and susceptible to similar diseases.

Companion Planting Tips for Success

• Know your spacing: Don’t overcrowd—good air circulation is still important even with companions.
• Start small: Try a few combinations and observe how your garden responds.
• Use flowers strategically: Calendula, nasturtium, alyssum, and marigolds are versatile and beneficial in many garden areas.
• Rotate crops yearly: Companion planting works best when combined with crop rotation to prevent soil depletion and disease.
• Observe and adapt: Your garden is a living system. Monitor pest levels, plant health, and growth patterns to fine-tune your combinations.

Final Thoughts

Companion planting is both a science and an art—rooted in tradition, enriched by observation, and adaptable to your specific space. As you plant in May, think beyond individual crops. Think of your garden as a community. When plants support one another, your entire garden ecosystem thrives.

Whether you’re growing tomatoes on a sunny patio, tending raised beds in the backyard, or managing a full-sized vegetable patch, companion planting gives you a smarter, more sustainable way to grow. So, pair wisely, plant with intention, and enjoy a season of abundance and harmony in your garden.