Spinach Companion Plants | Good and The Bad

Spinach is a delicious vitamin-rich leafy green that is quick to mature and can provide endless pickings all season long. With lots of varieties to choose from, there really is a spinach plant to suit even the most challenging climate zone. 

Spinach is easy to grow but will benefit from a little extra assistance in its plight to maturity by way of companion planting. It’s just a matter of ensuring that a ‘good’ companion plant is chosen rather than one that is detrimental to the health of developing crops. 

But don’t worry – I’ve done the hard work for you and simplified this growing technique to help you choose the perfect spinach companion plants.

What is Companion Planting

Companion Planting is a common gardening technique where different plant species are grown in close proximity to benefit one or both plants. Not only does this make it cost-effective, but it also boosts the health and yield of crops.

In gardening today, companion planting is frequently adopted to utilize growing space more efficiently. It is also widely used to improve the health of a garden without the use of pesticides using only organic methods, whilst still encouraging beneficial insects to assist with plant pollination.

Gardeners in China have been successfully growing rice plants for hundreds of years using a very successful method of companion planting. Rice growers maximize their plant yield by taking advantage of flooded growing conditions. 

An aquatic mosquito fern called Azolla is encouraged to grow which is then used as a companion to the rice plants. Although small, these ferns increase their numbers rapidly creating a weed-suppressing blanket around the rice plants. 

Not only do the Azolla plants release nitrogen into the water to encourage healthy growth, but it also acts as a water purifier keeping harmful bacteria to a minimum.

Benefits of Companion Planting

Companion planting boasts a myriad of benefits from improving biodiversity and minimizing pests to saving space and improving the nutrient ratio in the soil. There really are very few negatives. 

So, to satisfy your curiosity further, here’s a closer look at those advantages:

Space Saving: A large growing space can be a luxury which is why practicing companion planting can be extremely advantageous. With the right planting combination, it is possible for a gardener to maximize space thus improving the number of products that can be harvested. Interplanting smaller plants that are quick to mature such as radishes, salad leaves or scallions amongst taller slow growing plants like tomatoes or sweetcorn will increase harvest amounts. 

Improved Soil Health: There are many different ways companion planting can be used to improve growing conditions. Some plants can be used to improve the health and nutrient quality of soil to promote fast and healthy plant growth. Plants from the ‘Fabaceae Family’; are known for their ability to improve soil and growing conditions. Popular companion choices from this plant family are varieties of legumes, peas, or beans. These plants absorb nitrogen from the air which is then converted and released into the soil which neighboring crops use to their advantage.

Pest Control: The use of herbs and flowers is an efficient method of protecting main crops from pest attacks. Thanks to their strong fragrance herbs and flowers can help deter unwanted pests by masking the scent of the main crop confusing and diverting the pest away. These companions can also be used as a deterrent by attracting pests away from the main crop and onto the companion plant instead. This method is called Trap Cropping with the sole purpose of potentially sacrificing the companion plant in order to protect the main crop.

Increases Biodiversity: Planting an array of interesting flowers and herbs not only looks and smells great, it’s also a brilliant way of providing food and habitat for pollinators. In time, this can become a very appealing prospect for all manner of different insects and birds.

What To Consider When Selecting Companion Plants

It’s important to remember that although there are many positive benefits to this growing method, there must always be some consideration made by each individual gardener when it comes to selecting companion plants.

It’s always best to conduct a little research into any plant before growing and this is especially true when selecting companions. 

An easy mistake to make can be choosing a Perennial’ plant as a companion rather than one which is an ‘Annual’. There are lots of advantages to using both perennials and annuals as companions. However, if perennial plants are grown in a bed that is used to grow annual produce each year it can be problematic thanks to the major difference in each plant lifecycle. Always consider keeping annual and perennial companion plants separate.

Whilst companion planting is hugely beneficial, there can be a temptation to squeeze in lots of different plant varieties all in the same space. This can do more harm than good leaving the gardener with an unkempt mess that is hard to manage. 

Simplicity is key when selecting companion plants – one or two planting partnerships in each garden bed are more than enough, to begin with.

Best Companion Plants for Spinach

Whilst spinach is a popular choice thanks to how quickly it grows and how little maintenance it needs, it does come with some growing challenges. For example, it has a tendency to bolt when temperatures get too hot and can also be prone to pest infestations. For that reason, some of the best companion plants for spinach are those that provide shade or are highly scented and can detract bugs. 

Although there are many different varieties of spinach with varying tolerance for hotter climates, spinach normally prefers temperate growing conditions with an optimum temperature between 50°F and 60°F. Bolting/set seed occurs when growing conditions are consistently above this. 

Unfortunately, bolting has a detrimental effect on the flavor of spinach and can cause a bitter taste and toughness. To counteract this, eggplants are commonly used to alleviate this heat by creating shade during hot periods.

As with all plants, spinach is prone to pests so using plants with a strong fragrance can assist the spinach to avoid such attacks by confusing and diverting any unwanted visitors away from the plant. 

Companion plants can also be used to ensure the garden is being utilized fully. A good example of this is combining strawberry plants with spinach. There are no immediate benefits to each plant with regard to growth or pest protection, however, planting them together allows the maximum amount of growing space to be used which in turn increases the harvest amount.  

Good Spinach Companion Plants

Now let’s take a look at the best companion plants to grow with spinach and discuss what advantages each of them brings to this symbiotic relationship

Vegetables

  • Kale: Growing kale as a companion to spinach will not improve the flavor of the spinach plants or act as pest control. But, both kale and spinach have a preference for the same growing conditions so will thrive together. What this means is growing space is utilized more efficiently resulting in a bigger harvest. The taller kale plants will also provide shade to the spinach plants during the hotter months.
  • Lettuce and Bok Choy: Growing similar leafy greens alongside spinach is the perfect way to make full use of the growing space which allows a more diverse mixture of plants to be grown. Both lettuce and bok choy have similar needs and maintenance requirements as spinach which means tending to all varieties can be done at the same time. 
legumes being used as spinach companion plants
Legumes add nitrogen to the soil and offer shade
  • Peas, beans, and other legumes: Plants from the legumes family fix nitrogen in the soil which is gratefully received by spinach plants. Growing bush or climbing beans can also assist spinach plants by providing some shade which will give the plants added protection in the midday sun. 
  • Scallions: Scallions are a great pest deterrent thanks to their strong scent keeping away unwanted visitors from spinach plants such as aphids and mites. They are also very small fast growing plants that won’t compete for space, water, or nutrients.

Herbs and Flowers

  • Borage: Borage will benefit spinach plants greatly if used as a companion. If grown together borage plants will improve the health and growth rate of spinach. The strong fragrance of borage is also known to keep pests such as wireworms and cabbage loops at bay by both deterring pests and encouraging beneficial predators.
Marigolds
Borage is an excellent companion plant
  • Marigolds: Marigold flowers will not only attract pollinators and other beneficial insects but will also repel harmful predators thanks to their strong fragrance. These very useful companions can also repel pests in the soil too, keeping root-knot nematode numbers to a minimum.
  • Cilantro: Growing herbs is the perfect way to encourage pollinators and beneficial insects to a garden. Cilantro will act like a magnet for such visitors when in flower. Cilantro will thrive in the same growing environment as spinach and when used as a companion cilantro can improve the flavor of spinach leaves. 

Bad Companion Plants for Spinach

It is important to be mindful that there are lots of bad companion plants for spinach which are best avoided:

Here are some examples which should be avoided:

  • Pumpkins: Pumpkins thrive in nutrient-rich soil with lots of room to spread out. Pumpkin vines have a tendency to scramble in all directions creating a thick canopy of leaves that will completely cover spinach plants, starving them of light and airflow. Pumpkins will also work in direct competition with spinach for valuable nutrients in the soil. 
  • Fennel: There are few companion partners who succeed when grown with fennel. Fennel will stunt the growth of spinach plants and should not be grown in the same area. If fennel is to be grown, it is best to keep plants in containers.
  • Potatoes: Growing potatoes nearby spinach is not a good idea due to them being very greedy feeders. Potato plants will work in direct competition for nutrients and water in the soil leaving very little for spinach plants.

You may also like to read Companion Plants for Mustard Greens | Good and The Bad

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Ben's horticultural interest grew when graduating from Hertfordshire University in 1997. Having contributed to numerous publications including Better Homes & Gardens, Garden Design Magazine, and The English Garden. He is also the author of Propagating Houseplants Made Easy.