When planning your garden, potatoes offer a unique challenge, since there are many plants that grow well in close proximity to potatoes, but there are also a group of plants you should avoid planting near them. An understanding of companion planting strategies will help you understand how best to plan your garden and where to plant potatoes without necessitating a lot of heavy-duty chemical pesticides.
Principles of Companion Planting
Companion planting can be defined as the practice of planting different species of plants close together based on their ability to enhance one another in some way. Plants can be defined as good companions for a number of different reasons, and the gardener may want to emphasize one reason over others when laying out a garden. Common reasons why plants might be regarded as good companions include:
- Non-competing growth habits: Plants may have different but complementary growth habits that do not compete with one another. Pairing tall upright plants with ground-hugging vines, for example, can offer efficiency in the use of garden space. Or pairing deep-rooted vegetable with shallow-rooted vegetables may offer similar efficiency.
- Similar growth needs: Plants may have similar needs for fertilizing, water, or sunlight, which makes it easier to take care of them. Pairing together plants with high water needs, for example, can make it easier to water all of them at the same time.
- Pest deterrent: Some plants may be known to repel certain insect pests that feast on a particular plant. Marigolds, for example, are good companions for many plants for this reason. Other plants actually draw in beneficial insects that serve as predators for harmful insects.
- Soil balance: Plants use different nutrients in the soil, preventing depletion of the soil and reducing the need for fertilizing.
- Nutrient-rich: Some plants may actually improve the nutritional value of the soil. Legumes, for example, are good companions for many plants because they "fix" nitrogen and make it available for many other plants.
- Flavor enhancer: Some plants may enhance the flavor of other edible plants when they are grown close together.
Good companion planting strategies are especially important in small gardens or wherever careful space planning is needed.
Companion planting can be more complicated than it first appears since it requires a gardener to prioritize the benefits and drawbacks of pairing the different companions in a particular garden setting. What is a good companion plant in one garden may not be a good companion in another garden in a different region. The preferences of the gardener also play a role. For example, a gardener devoted to organic methods may view good plant companions differently than a gardener who is not squeamish about the use of fertilizer.
Good Neighbors for Potatoes
Potatoes are deep-rooting vegetables, which logically suggests that the best companions will be those with above-ground growth habits that do not infer with the root systems of the potatoes. Lettuce, spinach, scallions, and radishes are shallow-rooted veggies that are a good choice for occupying the spaces between potato plants. Because potatoes are harvested late in the season, the best choices for planting right around the potato hills will be early-season vegetables that will be harvested well before you need to stomp around the garden to keep up the potatoes.
There are several plants that are said to enhance the flavor of the potato tubers, including chamomile, basil, yarrow, parsley, and thyme (they also welcome in beneficial insects). Beans, cabbage, and corn all will help potatoes grow better and hence improve the flavor of the tubers.
Beans and other legumes are good companion plants for most vegetables since they increase nitrogen levels in the soil.
Horseradish is said to make potatoes resistant to disease, and petunias and alyssum will also attract beneficial insects that feast on insects destructive to potatoes. Colorado potato beetles are a particular problem for potatoes, and among the plants that repel this damaging pest are tansy, coriander, and catnip.
Neighbors to Avoid
Proper companion planting technique can also mean not putting some plant species close together if they have a bad influence on one another. Some reasons for avoiding close planting include:
- Plants may influence the taste of other plants negatively
- Plants may compete with one another for sunlight, soil nutrients, or space
- Plants may lure the same destructive insects
- Plants may have similar disease susceptibility
Although it is in the nightshade family, you should avoid planting potatoes near any other plants in the nightshade family. It is even best to avoid planting potatoes is the same soil where nightshade plants have recently been grown. This includes eggplant, peppers, and tomatoes. Since potatoes are in the nightshade family, and hence they are susceptible to many of the same diseases as other members of the family. Planting nightshade species close together (either in space or in time) creates optimal conditions for certain fungal and bacterial diseases to thrive. You should allow a full two years before replanting a nightshade plant in the same soil that has previously grown other nightshade plants.
There are a number of plants that apparently increase the likelihood of potato blight. These include raspberries, sunflowers, pumpkins squash, and cucumbers.
Asparagus, carrots, fennel, turnips, and onions seem to stunt the growth of potatoes.
Good Companions for Potatoes
Plants to Avoid Planting Next to Potatoes