An Introduction to Companion Planting

Jun 4, 2019 | Gardening, Plant Basics

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It’s always so exciting when it’s time to start planning the placement of your plants in the garden. Most people think about sunlight requirements and spacing but understanding how plants interact with one another is vital to the overall health of your garden. So, what’s the big deal? By not thinking about plant relationships, you could be ruining your garden before it even starts. Here are a few reasons that this is so important.

  • Soil Resources
  • Pest, Disease, & Weed Management
  • Slowed Plant Growth or Natural Enemies
  • Beneficial Pairings
  • Crop Rotation

Soil Resources:

Corn is heavy nitrogen and phosphorous users

As we know, all plants require micro and macro nutrients to survive. These nutrients serve different purposes, from cell wall strength to seed production, disease resistance to photosynthesis functions. Since all plants are different, their nutritional requirements will vary. Because plants get the majority of their nutritional needs from the soil, you want to be mindful what the plants will need to grow and produce. The soil does not have unlimited resources so you don’t want to plant a bed where all your plants are heavy nitrogen users, because it will quickly deplete the soil’s resources. This will leave you with plants that will either not survive or will have stunted growth with very low production as they are not getting what they need to grow properly.

This can be solved partially by fertilizing regularly during the growing season, making sure your plants are getting all the nutrients they need. A better, less costly and lower maintenance solution is planning your garden for plants that compliment one another, allowing resources to be used more evenly between the plants. Having a nitrogen heavy user next to a potassium heavy user allows both plants to get the nutrients they need without competing for resources.

Pest, Disease, & Weed Management:

It’s no surprise that having a garden entices certain critters to flock to it. From squash bugs to cucumber beetles, caterpillars to aphids, they can’t wait to feast on your hard work. Sure, you can drown your plants with pesticides to get rid of them but why not go the natural route? Planting certain plants next to one another can be beneficial for pest prevention or pest deterrent. For example, planting tomatoes and corn next to each other is a bad idea because corn ear-worms will destroy both corn and tomatoes. By having them close the pest can go from one plant to another with no problems. While planting them separately doesn’t guarantee that you won’t get worms on your plants, you are making it less likely.

While some plants should not be planted close together because they could cause pests to be attracted, the same can be true about pest prevention. Planting marigolds among your plants can help deter aphids, potato beetles, corn ear-worms, squash bugs, mosquitoes, tomato worms, and nematodes just to name a few. Marigolds are great because they get along with almost all plants so it’s a no brainer to spread these out in your garden beds. For a more detailed list of herbs and flowers that repel specific pests like ants, flies, slugs, aphids and more, check out these great articles by Mother Nature Network and Happy DIY Home. Careful planning can really help prevent an infestation during the growing season.

Tomato Blight Can Spread to Squash and Potatoes

The same is true with disease prevention. Tomatoes, squash and potatoes are vulnerable to the same strain of blight, meaning if you plant them next to each other than you are risking losing all your plants if one succumbs to blight. This is also true with carrots and parsnips, they are vulnerable to the same kind of diseases so by planting them together you are increasing the risk to your plants. While this will not solve your plant’s ability to get a disease, it can help prevent it by minimizing the spread of the disease to multiple plants.

Companion planting can also help you think ahead to what kind of growing conditions your plants will need to reduce the chance of disease. For example, planting lettuce and parsley together is not recommended because the parsley can quickly overcrowd the lettuce. This will not only lead to stunted lettuce growth, but will reduce sunlight, airflow, and water going to your plant, increasing it’s chance of disease (to Farmers Almanac).

Weed growth is also another important factor to consider when planning your garden beds. Who wants to spend all day pulling weeds? While mulch is great at reducing the amount of weeds that can grow in your garden, I like to plant beneficial herb plants that will add to the ground cover while giving me the ability to use fresh herbs all year long. Thyme is one of my all-time favorites. Planted with tomatoes or eggplant, the thyme will spread to cover the ground, preventing weeds while benefiting my taller plants. This will also help keep moisture in the soil, prevent pests like tomato horn worms, flea beetles, and corn ear-worms.

Slowed Plant Growth or Natural Enemies

Some plants just don’t thrive next to each other. When planning your garden, you want to make sure to check that your plants are not natural enemies prior to planting to avoid the heartache of your plants not thriving in your garden. Plants that are not compatible can cause stunted growth and reduced seed production. For example, sage and cucumbers do not get along. Sage will greatly reduce a cucumber’s ability to grow. Same is true with pole beans and beets, dill and carrots, peas and onions.

Beneficial Pairings:

The good news is that there are plenty of plants that absolutely love being together! The most well known example of beneficial companion planting is the “Three Sisters”. The three sisters are pole beans, corn, and squash. Each plant contributes to the success of the other plants:

  • Beans: nitrogen can be found in the air, which the beans can convert into a plant friendly form into the soil. This is great because both corn and squash are heavy nitrogen users.
  • Corn: the corn acts as support for the beans to grow.
  • Squash: the squash acts as ground cover for the beans and corn, allowing weed prevention and reduces water evaporation from the soil.

While you can grow each one separately, why not grow them together to get the best from each plant? The combination of plants that work together is extensive. Planting tomatoes and jalapenos together can cause the tomatoes to have a slightly spicy taste while mellowing out the heat of the peppers. I like using The Old Farmer’s Almanac and Burpee companion plant lists when planning my garden to start with, and I’ll do a refined search if I need more specific information.

Crop Rotation:

Changing the Location of Your New Plants Can Greatly Impact Your Soil’s Fertility

Since we know different plants need different resources, and certain plants are combative with one another, it is important to take this into account during seasonal planting. You don’t want to plant the same plants year after year in the same location without properly amending your soil because the ground will be depleted of the resources the plants need to grow. Rotating your plants can help reduce this, since the needs will be different and some plants, like beans and peas, add beneficial nutrients into the soil . Plants also have different root depth, meaning if you plant shallow rooted plants in the same bed year after year, the top of the soil will be depleted of it’s resources but the inner layers will be fine. By changing the plant types, you are more evenly using the soils resources.

This is also important in terms of pest and disease reduction. If you are planting varieties that attract the same pests, you are making it more and more likely every year that you will get those pests. Diseases can live in the soil, so planting the same thing year after year can set you up for failed crops from the start. By rotating planting beds you are essentially interrupting both pest and disease cycles, improving your chances for healthy, happy plants. For more information of crop rotation and schedules, check out this great article by the Thurston County.

So Now What?

Gardening is such a satisfying activity, so why not set yourself up to have the best, most productive garden you can? Companion planting is vital to making sure your plants are getting what they need to not only survive, but be productive and healthy. I know it may seem a little overwhelming because there is so much to consider, but just a day of planning can make a world of difference. When planning my garden every year, I like to complete the following steps to ensure success:

  • List everything I want to plant for the season.
  • Check companion plants to see what plants are strong companions and what plants are combative with one another.
  • Start planning my beds to ensure the companions are together and the combative plants are far away from each other.
  • Taking spacing and ground cover into account, I plan where to place neutral plants without over crowding.

Once that is done, I have a clear plan of what to plant where and how many of each plant will fit. This also gives me an opportunity, if I see available space, to do further research into what is compatible to plant, giving me a chance to try something new! I save these plans year after year so I can make sure I’m rotating my crops properly.

While using companion plants will not solve every gardening problem, it will help make your garden the best it can be. You will help keep your soil fertile, reduce pests, diseases, and weeds, and help prevent your plants from stunting growth with one another. If done properly, your plants’ growth will benefit the rest of your garden, giving you higher yields and seed production.

Good luck with planning your garden and we hope this article helped you! Leave a comment about what companion plants you are trying this season!

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Hello everyone! My name is Angie Mallery, and I’m the proud founder of Wicked Handy. This blog is my playground for sharing everything that makes life more joyful and practical—from crafting and cooking to gardening and DIY projects. I’m thrilled you’re here and hope you find inspiration and enjoyment in what I love to do. Thank you for visiting!

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