Gardening isn't just about planting and watering; it's also about understanding how plants interact with each other and the soil they grow in. Imagine a garden where plants work together, not just to thrive but to enhance the very earth they grow in.
Making sure that your plant grows in good interaction with its surrounding plants and environment is the main principle of companion planting. Companion planting is a gardening technique where certain plants are grown together because they help each other thrive. Some plants can improve the soil, keep pests away, or provide support and shade for their neighbors, making the garden healthier and more productive.
In this article, we’ll dig into 17 companion plants that not only grow well together but also improve your soil's health and fertility. Grab your mind shovels and let’s start digging into each one of them!
Starting with…
1. Clover (Trifolium spp.)
Clover, as a nitrogen-fixing plant, enriches soil fertility by transforming atmospheric nitrogen into a usable form for plants, consequently augmenting the soil's nutrient profile. Moreover, the growth characteristics of clover aid in reducing soil erosion and fostering a resilient soil structure, establishing it as a beneficial partner in sustaining soil health.
Growing Requirements for Clover
| Sunlight Requirement | Full sun, partial shade |
| Soil Texture Requirement | Well-drained, moist soil |
| Soil PH | Acidic soil is preferred |
| Temperature | Hardy, various temperatures |
| Relative Humidity | No specific requirements |
| Optimum Watering Schedule | Moist soil, drought-tolerant |
| Hardiness Zone | USDA Zones 3-10 |
| Harvest Index | Not for harvest |
| Propagation | Propagated by seeds |
| Maintenance | Regular watering, periodic mowing |
Adding lime can be important for balancing soil pH and promoting optimal growth. It's important to manage competing plants before planting to avoid weed problems. Clover seeds are small and can be mixed with lime or fertilizer to make them easier to distribute during planting. It's best to avoid using solid fertilizers that could potentially damage the plant's roots.
2. Peas (Pisum sativum)
Peas are beneficial for soil improvement because they can fix nitrogen from the air into the soil, enriching it with essential nutrients. This natural process helps enhance soil fertility, promoting healthier plant growth not just for peas but for other crops as well. As a result, planting peas in rotation or alongside other crops can contribute significantly to maintaining soil health and productivity.
Growing Requirements for Peas
| Sunlight Requirement | Full sun |
| Soil Texture Requirement | Well-draining, loamy, organic |
| Soil PH | Slightly acidic to neutral |
| Temperature | Mild, cold tolerance |
| Relative Humidity | Adequate soil moisture |
| Optimum Watering Schedule | Regular, avoid soggy |
| Hardiness Zone | USDA zones 3-10 |
| Harvest Index | Variety-dependent, maturity |
| Propagation | Direct planting, spacing |
| Maintenance | Watering, support, mulching |
Use stakes, trellises, or pea fencing to help vining pea plants grow upright. Be careful with fertilizers, especially those high in nitrogen, as they can make the plants focus too much on leaves instead of making pods. Harvest the peas as soon as they're ready to keep the plants producing more.
3. Buckwheat (Fagopyrum esculentum)
Buckwheat is a beneficial crop for soil improvement as it can thrive in various soil types and doesn't require specific pH levels. It also doesn't need a lot of water or fertilizer to grow successfully. Additionally, its ability to suppress weeds and improve soil structure makes it a valuable companion plant for maintaining soil health.
Growing Requirements for Buckwheat
| Sunlight Requirement | Full sun, partial shade |
| Soil Texture Requirement | Any type, good drainage |
| Soil PH | Slightly acidic to neutral |
| Temperature | Warm, not frost-tolerant |
| Relative Humidity | Moderate humidity |
| Optimum Watering Schedule | Regular watering, moist soil |
| Hardiness Zone | USDA zones 3-10 |
| Harvest Index | Mature seeds harvest |
| Propagation | Direct seeding, proper spacing |
| Maintenance | watering, fertilization, weeding |
Buckwheat doesn't need much, but adding some balanced organic fertilizer before planting can help it grow better. Also, it's a good idea to get rid of mature plants after they flower to stop too many new plants from growing.
4. Alyssum (Lobularia maritime)
Alyssum is a great addition to improve soil because it helps keep the soil moist, prevents erosion, and attracts pollinators, which all contribute to a healthier and more diverse environment. Its shallow roots are especially helpful in preventing soil erosion on sloped or vulnerable areas.
Growing Requirements for Alyssum
| Sunlight Requirement | Full sun, partial shade |
| Soil Texture Requirement | Moist, well-draining soil |
| Soil PH | Slightly acidic to neutral |
| Temperature | Adaptable, temperate weather |
| Relative Humidity | Moderate humidity tolerance |
| Optimum Watering Schedule | Maintain moist soil |
| Hardiness Zone | Zones 4-9 |
| Harvest Index | Primarily ornamental |
| Propagation | Seeds, cuttings |
| Maintenance | Regular water, pest control, deadheading |
Don't use too much fertilizer because it might make the plant grow too many leaves and not enough flowers. Keep an eye on humidity, especially in humid areas, to stop fungus from growing. For tall plants, give them something to lean on like a trellis so they don't flop over.
5. Dill (Anethum graveolens)
Dill is a valuable asset for soil improvement as it maintains soil health, attracting beneficial insects, and acting as a natural repellent for certain pests. Its deep root system facilitates improved soil aeration and nutrient circulation, enhancing overall soil fertility and supporting plant growth.
Growing Requirements for Dill
| Sunlight Requirement | Full sun, some shade |
| Soil Texture Requirement | Loose, well-draining soil |
| Soil PH | 5.5-7.0, adaptable |
| Temperature | Cold-hardy, optimal 70°F |
| Relative Humidity | Tolerant, no specifics |
| Optimum Watering Schedule | Moist soil, not waterlogged |
| Hardiness Zone | Zones 3-11, variety-dependent |
| Harvest Index | Foliage, seeds harvested |
| Propagation | Seeds, self-seeding |
| Maintenance | Regular water, pruning, pest monitoring |
Dill doesn't need a lot of fertilizer and actually prefers soil that's not too rich. Don't use too much fertilizer, as it can make the plant grow too many leaves but with less flavor. Keep picking the leaves often to make the plant grow more and avoid it flowering too soon and making seeds.
6. Mustard (Brassica spp.)
Mustard holds the capability to act as a natural biofumigant, releasing compounds that suppress harmful soil-borne pathogens and pests. Mustard's deep root system helps improve soil structure, enhancing water infiltration and nutrient availability for other plants.
Growing Requirements for Mustard
| Sunlight Requirement | Full sun, partial shade |
| Soil Texture Requirement | Fertile, well-draining soil |
| Soil PH | Slightly acidic soil |
| Temperature | Cool-season crop |
| Relative Humidity | Moderate humidity |
| Optimum Watering Schedule | Consistent moisture, avoid soggy soil |
| Hardiness Zone | Various zones |
| Harvest Index | Greens, mature seeds |
| Propagation | Seeds, direct sowing |
| Maintenance | Soil moisture, pest control |
When mustard plants are around 3 to 4 inches tall, they can benefit from a fertilizer with a lot of nitrogen. Make sure baby greens don't get too much direct sunlight; this helps keep them tender and flavorful.
7. Beans (Phaseolus spp.)
Bush beans are unique because they can fix nitrogen, which means they add nitrogen to the soil. This makes them a valuable part of crop rotation for many farmers, as nitrogen is crucial for growing healthy, productive plants. This nitrogen-fixing ability is a distinctive feature of beans and other legumes.
Growing Requirements of Beans
| Sunlight Requirement | Full sunlight |
| Soil Texture Requirement | Well-drained loamy |
| Soil PH | 6.0 – 6.8 |
| Temperature | 70°F – 85°F |
| Relative Humidity | Moderate humidity |
| Optimum Watering Schedule | Consistent moderate watering |
| Hardiness Zone | Zones 3-10 |
| Harvest Index | Mature seed harvest |
| Propagation | Direct seeding |
| Maintenance | Weeding, crop rotation |
Given their nitrogen-fixing capability, it is advisable to limit the application of nitrogen fertilizers, allowing beans to naturally enhance soil fertility. Position the planting site to receive ample sunlight and maintain optimal soil conditions to achieve the best agronomic outcomes. Proper plant spacing and adequate air circulation are essential to mitigate the risk of fungal pathogens.
8. Lentils (Lens culinaris)
Lentils are great for soil since they provide essential nutrients like nitrogen, improve soil structure with their deep roots, and reduce erosion by covering the soil. They also help control weeds, keeping the soil healthy and fertile for other plants.
Growing Requirements of Lentils
| Sunlight Requirement | Full sun, south/east |
| Soil Texture Requirement | Sandy loam, fertile |
| Soil PH | 6.0-6.5, pH 8.0 max |
| Temperature | 65-85°F, cooler climates |
| Relative Humidity | 30-40%, moderate |
| Optimum Watering Schedule | 1 inch/week, avoid waterlogging |
| Hardiness Zone | Cool climates |
| Harvest Index | Dry pods harvest |
| Propagation | Direct seed planting |
| Maintenance | Use compost, trenching |
Avoid saline, boron, or sodic soils; stop watering when pods dry; tolerate drought but not waterlogging.
9. Soybeans (Glycine max)
Soybeans are beneficial for soil improvement since they hold the capacity to fix nitrogen from the air into the soil, enriching it with essential nutrients. Their deep root system helps improve soil structure and aeration, enhancing water infiltration and nutrient availability for other plants.
Growing Requirements of Soybean
| Sunlight Requirement | Full sun exposure |
| Soil Texture Requirement | Well-drained soil |
| Soil PH | Adaptable pH range |
| Temperature | Warm-season crop |
| Relative Humidity | No specific requirement |
| Optimum Watering Schedule | Keep soil moist |
| Hardiness Zone | Warm climate |
| Harvest Index | Flowering stage harvest |
| Propagation | Seed planting |
| Maintenance | Fertilize poor soil |
Soybeans grow in warm soil conditions, making them well-suited for planting during the summer months. When cultivating soybeans to improve nutrient-poor soil, adding a balanced organic fertilizer beforehand can enhance their growth and yield. This practice ensures that the soil has the necessary nutrients to support healthy soybean development and contribute to overall soil improvement.
10. Lupines (Lupinus spp.)
Lupines are essential for improving soil knowing that they add important nutrients, especially nitrogen. Their deep roots help break up and aerate the soil, making it healthier. They can grow well in poor soil, which helps make the ground more fertile.
Growing Requirements of Lupines
| Sunlight Requirement | Full sun is preferred |
| Soil Texture Requirement | Well-draining soil |
| Soil PH | Neutral to slightly acidic |
| Temperature | Moderate climate is preferred |
| Relative Humidity | Moderate humidity |
| Optimum Watering Schedule | Regular, avoid waterlogging |
| Hardiness Zone | Suitable for a wide range |
| Harvest Index | Not typically harvested |
| Propagation | Seeds or cuttings |
| Maintenance | Minimal fertilizer needed |
Cool summers suit them best, as they struggle in hot, humid climates. They need regular watering without waterlogging and minimal fertilizer to avoid hindering flowering. Propagation can be done from seeds or cuttings, and maintenance involves avoiding extreme conditions and using light mulching in hot climates to retain moisture and keep roots cool.
11. Alfalfa (Medicago sativa)
Alfalfa is an excellent companion for soil improvement because it enriches the soil with nitrogen through its nitrogen-fixing ability, enhancing overall soil fertility. Its deep root system helps to break up compacted soil, improving soil structure and aeration. Additionally, alfalfa adds organic matter to the soil when it decomposes, further boosting soil health and productivity.
Growing Requirements of Alfalfa
| Sunlight Requirement | 6-8 hours sunlight |
| Soil Texture Requirement | Well-drained, varying depths |
| Soil PH | Slightly acidic to neutral |
| Temperature | 65-77°F optimal range |
| Relative Humidity | Consistent moisture needed |
| Optimum Watering Schedule | Keep soil moist |
| Hardiness Zone | USDA zones 3-10 |
| Harvest Index | Multiple annual harvests |
| Propagation | Direct sowing, depth controlled |
| Maintenance | Monitor soil moisture |
Alfalfa can handle cold weather when it starts growing but becomes sensitive to it after sprouting two sets of leaves. The ideal planting seasons are spring, late summer, and autumn. For best planting results, use equipment that ensures the seeds are planted at the right depth and the soil is packed firmly.
12. Comfrey (Symphytum officinale)
Comfrey is an excellent soil companion because its deep roots improve soil aeration and water penetration, while its rapid growth and dense foliage suppress weeds and reduce nutrient competition. Furthermore, the nutrient-rich leaves of comfrey can be harvested and used as a natural fertilizer, enhancing soil fertility.
Growing Requirements of Comfrey
| Sunlight Requirement | Partial to full sun |
| Soil Texture Requirement | Moist, fertile soil |
| Soil PH | 6.0 to 7.0 |
| Temperature | Best planted in spring |
| Relative Humidity | Moderate soil moisture |
| Optimum Watering Schedule | Water when soil dry |
| Hardiness Zone | Very hardy perennial |
| Harvest Index | Harvest leaves and roots |
| Propagation | Root cuttings, crown divisions |
| Maintenance | Weed control, nitrogen fertilization |
Comfrey is tough and can handle different weather conditions. When planting, make sure to put the roots deep enough and leave space between plants. Give it enough nitrogen fertilizer and keep the area weed-free to help it grow well. Be careful, though, because it can spread quickly and take over if not managed properly.
13. Borage (Borago officinalis)
Borage serves as a beneficial soil companion due to its ability to thrive in nutrient-deficient soils, enhancing soil quality as its leaves decompose. Furthermore, its attraction of pollinators such as bees assists in pollination for neighboring plants, thereby supporting the overall health of the ecosystem.
Growing Requirements of Borage
| Sunlight Requirement | Full sun to partial shade |
| Soil Texture Requirement | Well-drained, adaptable soil |
| Soil PH | Tolerant, prefers slightly acidic |
| Temperature | Heat and cool tolerant |
| Relative Humidity | No specific requirements |
| Optimum Watering Schedule | Even moisture, slight drying |
| Hardiness Zone | Various zones are adaptable |
| Harvest Index | Leaves, flowers, seeds |
| Propagation | Commonly from seeds |
| Maintenance | Periodic phosphorous feeding |
Borage has specific needs that ensure its optimal growth. These include a preference for well-drained soil with moderate moisture levels and a slightly acidic pH. It thrives in full sun but can tolerate partial shade, and it benefits from occasional feeding with a phosphorus-rich fertilizer to promote flower production.
14. Chamomile (Matricaria chamomilla)
Chamomile is beneficial for soil improvement because it accumulates nutrients, enriching the soil as its leaves break down. Its deep roots also aerate the soil, aiding in water and nutrient absorption for nearby plants. Moreover, chamomile attracts helpful insects and prevents weed growth, enhancing soil health and fertility in the garden. Did you also know Chamomile is also a companion plant for basil? Read our related blog post – The Best Basil Companion Plants to Grow
Growing Requirements of Chamomile
| Sunlight Requirement | Full sun, partial shade |
| Soil Texture Requirement | Well-drained, rich |
| Soil PH | Neutral, 5.6-7.5 range |
| Temperature | Moderate, up to 100°F |
| Relative Humidity | Moderate, avoid excessive humidity |
| Optimum Watering Schedule | Inch per week, moderate dryness |
| Hardiness Zone | USDA Zones 2-9 |
| Harvest Index | Summer months |
| Propagation | Seeds, dividing plants |
| Maintenance | Low maintenance, pruning |
Regular pruning to encourage bushier growth and continuous flower production. Additionally, occasional deadheading is beneficial to promote more blooms and maintain a tidy appearance. These practices help maximize the plant's overall health and aesthetic appeal, ensuring a vibrant and productive chamomile garden.
15. Rye (Secale cereale)
Rye enhances soil structure, allowing better water infiltration and root growth for other plants. It acts as a dynamic accumulator, storing nutrients from deeper soil layers and releasing them as biomass decomposes, enriching the soil. Rye also suppresses weeds, controls erosion, and can be used as green manure, contributing to overall soil health and fertility.
Growing Requirements of Rye
| Sunlight Requirement | Full sun, partial shade |
| Soil Texture Requirement | Well-drained soil |
| Soil PH | Neutral to slightly acidic |
| Temperature | Frost-tolerant |
| Relative Humidity | Moderate levels |
| Optimum Watering Schedule | Regular, slight dryness |
| Hardiness Zone | Varies by variety |
| Harvest Index | Soil improvement focus |
| Propagation | Direct seeding |
| Maintenance | Low maintenance |
Wide spacing to allow it to serve as trellises for garden peas in spring. When grown in very poor soil conditions, mixing a balanced organic fertilizer into the soil before planting can enhance its growth and performance. These practices ensure optimal results and productivity from cereal rye while also benefiting other plants in the garden.
16. Yarrow (Achillea millefolium)
Yarrow is a beneficial companion for soil improvement due to its deep root system, which helps break up compacted soil, improves aeration, and enhances water infiltration. It also acts as a dynamic accumulator, drawing up nutrients from deeper soil layers and enriching the soil when it decomposes
Growing Requirements of Yarrow
| Sunlight Requirement | Full sun, partial shade |
| Soil Texture Requirement | Adaptable soil types |
| Soil PH | Neutral pH preferred |
| Temperature | Warm conditions preferred |
| Relative Humidity | Tolerates some humidity |
| Optimum Watering Schedule | Drought-tolerant, light watering |
| Hardiness Zone | USDA Zones 3-9 |
| Harvest Index | Not harvested |
| Propagation | Division, seeds |
| Maintenance | Low maintenance |
Well-drained soil to prevent root rot or fungus and avoiding fertilizer to prevent overly aggressive growth. The plant prefers warm temperatures but can suffer heat damage if temperatures exceed 86°F. While it can tolerate some humidity, yarrow thrives in dry conditions and may suffer from root rot if the soil becomes too saturated.
17. Chicory (Cichorium intybus)
Chicory is beneficial due to its deep taproot system that breaks up compacted soil and enhances soil aeration. Its dynamic accumulator trait draws nutrients from deep soil layers, enriching the soil when the plant decomposes. Chicory's dense foliage acts as natural mulch, conserving soil moisture, suppressing weeds, and contributing organic matter to the soil, making it an excellent choice for promoting overall soil health and fertility.
Growing Requirements of Chicory
| Sunlight Requirement | Full sun. |
| Soil Texture Requirement | Well-drained, fertile |
| Soil PH | Neutral to slightly acidic |
| Temperature | Optimal germination temperature |
| Relative Humidity | Not specified |
| Optimum Watering Schedule | Regular, moist soil |
| Hardiness Zone | USDA Zones 3-9 |
| Harvest Index | Pre-flowering harvest |
| Propagation | Seeds or transplants |
| Maintenance | Mulching, frost protection |
Soil testing to determine fertilizer needs and avoiding nitrogen fertilization after the formation of heads to prevent bitterness. Additionally, chicory benefits from regular watering to maintain soil moisture and mulching for weed control and soil temperature regulation. Frost protection measures and appropriate timing of fertilization and thinning are also crucial for optimal growth and flavor development.
FAQs
What is companion planting?
Companion planting involves growing different plants together to benefit each other. For example, planting aromatic herbs like basil near tomatoes can deter pests through their strong odor and improve tomato growth. In a vegetable garden, it improves soil health, reduces pest problems, and can increase crop yields by fostering natural relationships between plants, such as using marigolds to repel nematodes from vegetable roots.
Why is companion planting a great way to manage pests in my garden?
By planting trap crops like radishes near susceptible plants, you can divert pests like flea beetles away from your main crops, effectively managing pest populations. On the other hand, you can also use insects to control pests. Parasitic wasps are beneficial insects that prey on harmful pests like tomato hornworms, naturally controlling pest populations and reducing the need for chemical pesticides. Aromatic herbs, through their strong scents repel insect pests like cabbage moths and carrot flies, protecting nearby crops such as cabbage and carrots.
How does companion planting promote weed suppression?
Planting ground covers like sweet alyssum or using living mulch between rows of vegetable beds has a beneficial effect as they suppress weeds by shading the soil and competing for nutrients. Cover crops like clover or vetch are planted to protect and enrich soil between main crops. They prevent erosion, add nutrients, and attract beneficial insects.
Can companion planting benefit small gardens or limited garden space?
Yes, by growing plants with complementary needs and functions in close proximity, you can maximize space and create healthier plants in small or urban garden settings. You can also use crops like pole beans as a companion plant to provide support. Pole beans, which climb tall supports, provide shade for lower-growing plants like lettuce, while the beans fix nitrogen in the soil, benefiting all nearby plants through heightened soil nutrients.
Conclusion
Companion planting can also improve soil health by being ground covers and organic fertilizers. The top 17 best companion plants to improve the quality of your soil include clover, peas, buckwheat, alyssum, dill, mustard, beans, lentils, soybeans, lupines, alfalfa, comfrey, borage, chamomile, rye, yarrow, and chicory.
Understanding their optimal growing conditions allows for efficient garden planning. Many of these plants harbor nitrogen-fixing bacteria in their roots, enriching soil nitrogen levels naturally. Armed with this knowledge, you can create a garden strategy that maximizes efficiency, replacing synthetic fertilizers with these beneficial plants for healthier, more sustainable gardening practices.
Armed with the knowledge of these top companion plants, including clover, peas, buckwheat, and others, you can strategically plan your garden for enhanced soil health and nutrient balance. By harnessing their natural abilities to fix nitrogen and serve as ground covers, you can reduce reliance on synthetic fertilizers, making your gardening practices more efficient and environmentally friendly. Embracing these natural wonders not only promotes healthier plants but also nurtures a sustainable garden ecosystem for years to come.
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Unleashing the Power of Companion Planting for Your Soil
