Companion planting offers numerous benefits in the garden. Firstly, it promotes biodiversity, creating a natural balance that discourages the spread of pests and diseases. Certain plant combinations work together to repel insects or attract beneficial ones, acting as a natural form of pest control.
Additionally, companion planting maximizes space utilization by intercropping plants with different growth habits. For instance, tall plants provide shade to shade-tolerant crops beneath them.
Furthermore, some plants enhance nutrient uptake and soil health by fixing nitrogen or suppressing weeds. Lastly, companion planting can improve pollination rates, leading to higher yields. Overall, it’s a sustainable and holistic approach that promotes healthier plants and a more harmonious garden ecosystem. The discovery process of finding more companion plants makes gardening enjoyable and more productive as well.
How does all of that apply to sweet potato companion planting? Let’s have a discussion from our perspective; we are self-sufficient in this root crop with several varieties growing throughout the year in our permaculture system, so we have firsthand knowledge of gardening with this plant, and have a good grasp on how it grows!
Understanding Sweet potato and Companion Planting
Sweet potatoes thrive in warm and tropical climates. They are heat-loving plants that require a good long, frost-free growing season. Here are some key climate requirements for sweet potatoes:
Temperature:
Sweet potatoes prefer daytime temperatures between 75°F (24°C) and 90°F (32°C). They can tolerate temperatures up to 95°F (35°C) but may suffer from heat stress if exposed to prolonged periods of extreme heat. Nighttime temperatures should be above 50°F (10°C).
Frost-free period:
Sweet potatoes are sensitive to frost and require a frost-free growing season of at least 4 to 5 months. They are typically grown as annuals in regions with shorter growing seasons.
Sunlight:
Sweet potatoes require full sun exposure to thrive. They need at least 6 to 8 hours of direct sunlight per day.
Rainfall:
Sweet potatoes prefer well-drained gardens, and excessive moisture can cause rot. They generally require around 20 to 30 inches (50 to 75 cm) of rainfall throughout the growing season. However, they can tolerate dry periods once established.
Soil:
Sweet potatoes prefer loose, well-drained soil with a pH range of 5.8 to 6.5. Sandy loam or loamy soils are ideal. Sweet potatoes are adaptable to different soil types but do not perform well in heavy clay soils.
It’s important to note that while sweet potatoes prefer warm climates, the plants can still be grown in regions with cooler or shorter growing seasons. In these areas, growing sweet potato slips indoors and transplanting them outdoors after the danger of frost has passed can help extend the growing season.
Additionally, some growers use black plastic mulch or row covers to help warm the soil and protect the plants in cooler climates, but we believe in the power of mulch and ground cover plants, and employ gardening methods that are as beneficial as we can make them, to as many elements in the system as possible.
What Plants make a good Companion.
Companion planting is the practice of growing certain plants together to benefit each other in terms of pest control, pollination, and nutrient uptake.
When it comes to growing sweet potatoes, there are some companion plants that are known to be beneficial, noting that many of these plants will not grow reliably enough to be included in our own garden, but they are listed here for growers in cooler climates where sweet potato plants can be grown with care. Be mindful that sweet potatoes like space and enjoys climbing.
Beans:
Beans, such as bush beans or pole bean plants, are great companions for sweet potatoes. They help fix nitrogen in the soil, which is beneficial for sweet potato growth. Again, be aware that sweet potatoes will climb aggressively. Pole beans may be preferred in this situation.
Marigolds:
Marigolds are known for their pest-repellent properties. Planting marigolds as companion plants near sweet potatoes can help deter pests like nematodes and aphids.
Oregano:
Oregano is a herb that can repel pests like aphids and spider mites. It can be planted near sweet potatoes to help protect them from these common pests.
Horseradish:
Horseradish is a root vegetable that can deter pests like flea beetles and aphids. Planting horseradish plants near sweet potatoes can help protect them from these pests.
Nasturtiums:
Nasturtiums are colorful flowers that attract beneficial insects like bees and predatory insects that feed on pests. They can be planted near sweet potatoes to attract pollinators and help control pests.
Herbs:
Herbs like basil, thyme, dill, chives, borage, summer savory, and oregano make good companion plants for sweet potato vines.
Garlic:
Garlic wards off pests and can be planted near sweet potatoes.
Remember to consider the specific growing conditions and climate in your region when choosing companion plants. Additionally, it’s important to space your companion plants appropriately to avoid overcrowding and competition for resources. Remember that sweet potatoes like to spread.
What to Avoid when Interplanting in the Garden.
This is the part of the article that we can share first-hand experience of gardening in the tropical zones, as this is our climate model.
As noted above, sweet potatoes are a tropical plant and during the growing season it runs rampant in large patches where the soil is not the best. The vine spreads in search of nutrients, and much of the vine’s energy is used in this activity.
These locations are good sweet potato green leaf harvesting but not so great for companions. It is usually the case that we have a poor return of potatoes in these locations, and we suspect the ground conditions are the primary reason. One thing we can share here is the scrambling vines that are full of leaf do attract insects, both beneficial and non-beneficial. Grasshoppers and other leaf-eating insects love the leaves.
Ginger and turmeric are two plants that can be considered for companion planting in this soil type. The vine will shade the soil while the ginger and turmeric rhizomes will help condition the soil for plants that will eventually follow.
On the contrary, areas where the ground is deep and fertile are definitely our most productive for tubers and are also far less vigorous in vine and leaf production. This makes these locations the best for companion planting, in our opinion. We have successfully planted tomatoes, galangal, rosellas, amaranth, and others with sweet potatoes in this area.
The production of any location is based on the vine’s aggressiveness, or lack of, in any area because a scrambling sweet potato vine will out-compete and climb over most other low-growing plants, particularly soft stemmed vegetables and herbs.
These sweet potato companion plants will most often be smothered in the vine’s pursuit for nutrients, if the vine needs to search. Supplying the required nutrients will suppress the scrambling habit to a manageable degree and help protect the companion plants.
Avoiding companion root damage at harvest time:
To intercrop sweet potato with other companion plants, one must have knowledge of the expected harvest times of each member of the beneficial plant guild where sweet potato is a member.
It seems a wonderful idea to plant a bunch of companion plants together and have them all perform, but it also seems a shame to have a root crop of sweet potatoes growing in amongst the roots of the other plants come harvest time when they are still healthy and viable.
The trick to avoiding this is to plan and time the plantings with the harvest times so the last harvest is the root crop. This is more problematic when companion plants like perennials are involved, as is often the case. To understand how deep the sweet potato grows the tubers or roots, an in-depth article on that topic can be found here.
These days, we prefer to have the sweet potato grow in a few designated areas and where an opportunistic plant does grow outside of these zones, little harm is done as we search and dig the odd potato from the gardens.
The Optimal Location for Sweet Potato Companion plants.
We have found that sweet potatoes will grow well under trees that have a small canopy. There are several reasons for this and they differ to the challenges facing smaller sweet potato companion plants.
- Sunlight is available under a small tree canopy around the edge of the shaded areas.
- The root system of the tree is far less likely to be harmed or disturbed when harvesting the potatoes.
- The tree is unlikely to be smothered by an aggressive vine, even though the sweet potato will climb many things.
- The sweet potato does not compete with the tree for nutrients as both root systems are active in quite different soil layers.
Planting Sweet Potato under large trees.
We have an article on this topic titled Will sweet Potato grow in Shade, found here, and it details the proposition of growing this vine in this location. You need to ask yourself what you want to harvest reliably for your garden before committing to this technique.
Sweet Potato Companion Planting in Temperate Zones
This is the challenge because the plants growing season is shortened for you. The vital element for you to consider here is the health of the soil. If you have fertile gardens, we suggest you start your sweet potato plants indoors when spring has arrived. It makes sense to get started on the sweet potato companion plants at the same time, if the timing is appropriate for your chosen varieties.
It is possible to interplant many of the plants listed at the top of this article with sweet potato successfully, with the caveat that the soil is fertile and deep. This allows the vine to put its energy into potatoes and not just vine. As mentioned above… the vine will smother the other companions if it has to search for nutrients.
Conclusions
While companion planting with sweet potatoes is a fantastic way to harness the natural behaviors and attributes of groups of plants, you should now be a little more aware that it is not a straightforward process. If you are planting vegetables, it is assumed you are doing so for food security and/or health reasons, so it is logical to eliminate risk where you can.
Being aware of the growth habits of all companion plants in a group-planting, and in particular sweet potatoes, is a first step towards your success.
Article by Tim Blanch for TheTropicalHomestead.com. He is a qualified Permaculture designer.
