As an avid gardener with over 20 years of experience in Wisconsin, I’m always looking for ways to maximize my crops’ health, yields, and flavor. And if there’s one fruit that Wisconsinites love come summertime, it’s juicy, sweet watermelon!
Over the years, I’ve found that growing watermelons can be rewarding but comes with its fair share of challenges. From heavy feeding needs to diseases and pests, it takes careful planning and maintenance to get a successful harvest. This is where companion planting comes in handy!
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An Introduction to Companion Planting
For those unfamiliar with the term, companion planting refers to the practice of strategically planting different crops together so that they can benefit each other. The right companion plants can help watermelons access more nutrients, repel pests, attract beneficial insects, and enhance flavor!
But not all plants make suitable companions. You must consider each plant’s unique needs and characteristics and what it contributes to the garden ecosystem. When done correctly, this plant matchmaking helps create a thriving garden that leverages each plant’s strengths.
What Watermelons Need to Thrive
Before choosing companion plants, it’s helpful to understand what watermelons require for healthy growth:
- Warm weather – As a heat-loving crop native to Africa, watermelons need consistently warm temperatures between 70-85°F once planted outdoors.
- Full sun – At least 6 hours of direct sunlight fuels growth.
- Rich, well-draining soil – Watermelons prefer soil with lots of organic matter and nutrients, with a pH of around 6.5.
- Consistent moisture – Plants need about 1-2 inches of water per week to stay hydrated, especially when fruits start to form.
- Space to spread – The vining growth habit can extend over 15 feet!
Even when their basic needs are met, watermelons can still struggle with:
- Pests – Cucumber beetles, squash bugs, and whiteflies love to munch on watermelon foliage and transmit diseases.
- Diseases – Powdery, downy mildew, wilt, and blight are common watermelon afflictions.
- Poor pollination – The sweet fruits won’t form without enough bee visitors.
This is where companion planting saves the day!
How Companion Planting Benefits Watermelons
The right companion plants grown around or near watermelons can provide tremendous benefits:
Pest control – Certain plants naturally repel pests that attack watermelon plants. For example, radishes deter cucumber beetles, while nasturtiums repel whiteflies.
Space efficiency – Low-growing greens like lettuce and spinach make excellent living mulch under and around watermelon vines.
Nutrient provision – Nitrogen-fixing plants like beans enrich the soil with nitrogen that watermelons need in high amounts.
Pollination assistance – Flowers like cosmos, zinnias, and bee balm attract the pollinators needed for fruit sets.
Weed suppression – Dense plantings help crowd out weed growth that could compete with watermelon plants.
Soil health – Deep-rooted cover crops improve water drainage and aeration in the soil.
Flavor enhancement – Herbs like basil and borage boost watermelon sweetness!
Now that you know the perks, let’s explore some of the top companion picks for watermelons.
Flowering Companion Plants
Pest-Deterring Marigolds
No companion planting mix is complete without marigolds! These cheery flowers deter pests, especially soil-dwelling nematodes that attack watermelon roots. The strong scent of marigold roots even forms a “protective zone” around neighboring plants. Choose the French or African marigold varieties over smaller flowering American types for maximum benefit.
Dual-Purpose Nasturtiums
Edible and ornamental, nasturtiums earn their keep by repelling aphids, squash bugs, whiteflies, and other watermelon pests. Their bright orange and yellow blooms also attract beneficial insects for natural pest control. Both the leaves and peppy seed pods make tasty additions to salads!
Vegetable Companion Plants
Quick-Growing Radishes
Easy-to-grow radishes deliver a one-two punch by luring cucumber beetles away from watermelon plants with their strong scent and deterring borers with their spicy flavor. Plant a new batch every 2-3 weeks for continual cucumber beetle control all season. For variety, try red, white, or even black radishes!
Nitrogen-Enhancing Beans
All legumes contain Rhizobium bacteria that draw nitrogen from the air and convert it into a plant-usable form – a process called “nitrogen fixation.” Beans are no exception, making them the perfect “fertilizer factory” for heavy-feeding watermelons. Opt for compact bush beans so these aggressive growers don’t take over!
Dual-Purpose Lettuce
Cool-weather lettuce thrives in the shade and moisture under watermelon vines. A living mulch layer helps conserve soil moisture and crowds out weeds. Buttercrunch and red leaf varieties are heat-tolerant options. Just be sure to harvest lettuce before watermelons ripen, so the falling fruits don’t crush the greens!
Herb Companion Plants
Aromatic Mint
Mint’s potent fragrance confuses pests and deters their feeding and egg-laying behaviors. It repels ants, aphids, and spider mites that afflict watermelons. Just be sure to plant mint in containers – otherwise, you’ll end up with an invasive mint monoculture taking over your garden!
Versatile Oregano
Oregano offers something for everyone- with over 40 varieties to choose from! Greek oregano’s neat, compact growth makes it perfect for garden beds. Pizza-flavored Italian oregano can be snipped fresh for marinara sauce. No matter which you choose, oregano protects against a broad spectrum of pests, from beetles to whiteflies.
Sweet Basil
Who doesn’t love fresh basil with their summer tomatoes and watermelon? Basil’s irresistible scent attracts gardeners and pollinators while deterring thrips, flies, mosquitoes, and even some blights. Research shows that basil grown near watermelons enhances their sugar content – so both the gardener and the fruits benefit! For compact growth, try bush basil varieties.
Other Helpful Companion Plants
With their deep root systems, cover crops like buckwheat, alfalfa, and clover improve soil health. Low-growing strawberries make great living mulch, while tall sunflowers support climbing watermelon vines (and seeds for snacking!).
Heat-loving southern peas, okra, and eggplant share the exact cultural needs of watermelons, making them ideal rotation partners between watermelon crops. This helps break pest and disease cycles in the melon patch!
As you can see, the possibilities for companion planting with watermelons are almost endless! I encourage you to experiment with plant companions and see what works best for your garden. Pay attention to each species’ nutrient needs, growth habits, and flowering times to create the most harmonious growing environment.
With suitable companions by their side, your watermelon vines will thrive and reward you with the sweetest summer harvest yet. So get planting!
