Companion Planting with Mushrooms

I was at the Boston Flower Show many years ago when I walked up to the Master Gardener booth and asked them: Have you guys ever worked with mushrooms? Nobody had. Such a shame! Luckily, more gardeners than ever are discovering that mushrooms offer amazing possibilities in the garden. There’s a popular impression that mushrooms can only be grown in cave-like environments, when in reality they grow all around us and have important roles to play in our local food ecosystem.

Why not treat mushrooms like what they actually are: a delicious, nutritious crop that can help us create a more complete and abundant landscape? Mushrooms are a very easy understory crop that plug into the same garden conditions you’re already building with mulch, shade, irrigation, and organic matter. You’re not replacing your vegetables. You’re adding a second harvest layer to the same square footage. And perhaps the best part is that they can come back  multiple times, often for years depending on the cultivation method you use. 

The answer is companion planting. This term just needs a quick reframe to include mushrooms. 

When gardeners talk about companion planting with plants, they often mean direct interactions between two species of vegetable crop: root exudates, nutrient sharing, pest confusion, nitrogen fixation, that kind of thing. With mushrooms, that’s usually not the point, at least not directly.

All of the mushrooms in this guide are decomposers, which means they eat dead organic materials like wood chips, straw, leaf litter, and the substrate inside a Plant & Grow mushroom starter block or sawdust spawn. They are not feeding on your living tomato roots but are consuming the organic material available to them in the soil or mulch. They’re doing something closer to composting, just faster. This process ultimately releases more nutrients into your soil and feeds your plants! 

The pairing suggestions are based largely on method and aligned environmental preferences: moisture, temperature, shade, and the kind of organic matter you already use as mulch. To varying degrees, mushrooms need high humidity, protection from drying winds and scorching sun, and relatively cool temperatures. Pairing should be designed to maximize benefits from those variables. 

It’s also a striking design move. Mushrooms look good in a garden, they make the whole system feel alive by adding more dramatic change, colors and textures. They move quickly and they help you use the “in-between” spaces gardeners usually ignore.

You’re not gambling with your vegetable patch. You’re upgrading the understory and creating one of the simplest and most beneficial intercropping plans out there.

The best option out there for controlling your environmental conditions further, so the mushrooms stay happy, is to utilize the MycoSphere garden bed system. Mushrooms and plants both benefit.

1. Plant & Grow Mushroom Starter Blocks are ready to bury outdoors and grow quickly in many different garden locations. This is the fastest way to get mushrooms outdoors, often growing under two weeks. They are simply nestled into a hole and covered over completely with garden soil or mulch, but only just (the mycology term is inoculated). As a helpful planting note: In most cases Plant & Grow Blocks should be planted at least 6-12 inches away from their companions to allow for root growth. For large and deeply rooted plants like tomatoes or melons, aim for 12-24 inches.  

2. Wood chip beds are exactly what they sound like: a bed or path section made of chips that have been seeded with sawdust spawn (a colonized sawdust block, not spores) that grows mushrooms while acting like premium mulch. Spawn is simply broken up and layered or worked into the material. These usually grow within the same season, but on the order of months. 

3. Hardwood Logs that have mushroom networks coursing through them are the longest lasting method of mushroom production there is. Introduce the spawn only once and logs can produce mushrooms for 5+ years. Holes are drilled all around the logs in offset lines, spawn is inserted and kept protected with wax. Mushrooms typically take anywhere from 6-18 months to appear.

Let the plants be your guide to keep it simple. Planting the appropriate fungal companion should be done once the plant has grown just big enough to provide benefits like shade and humidity. It could still be a few weeks before mushrooms appear so this ensures a great environment for your baby mushrooms to form. 

Bed and log species are exceptions to this rule because they take several months or years to grow, so they can be planted at the same time or under already established larger plants.  

Consider how fast the plants will grow and how fast the mushrooms will grow. What stage will each one be at in, for example, two weeks? If the plants aren’t at the right stage to provide the intended shade, it could be advantageous to plant your mushrooms a little later. It also doesn’t hurt to ask yourself what that space will look like in the future. Will that plant still be around to provide shade or will another crop be there to provide shade for the next wave of mushrooms? 

Below you’ll find mushroom species, grouped by average growing temperature, along with the best method and a perfect veggie companion. Remember that these are recommendations and the possibilities are vast if you apply the outlined principles well!

Best method: Plant & Grow

Plant companion: Peas (trellis shade early)

Why: Snow oyster’s brilliant white pops out against the often muddy tones of early spring. They can take a few weeks to get going in the cold, which is just enough time for the peas to create the microclimate they love.

Best method: Plant & Grow

Plant companion: Broccoli

Why: This is a unique species that deserves a lot more experimentation outside. Broccoli will provide great conditions over plenty of time to allow these regal mushrooms to crown. 

Best method: Plant & Grow

Also works: Bed/mulch

Plant companion: Beets

Why: Both species are cold adapted and can be grown very early and very late in the season. With lots of moisture, Nameko will form a slimy protective layer that can combat freezing and moisture loss. Nameko likes the cold so much, we’ve seen it produce in the fridge on multiple occasions!

Best method: Plant & Grow

Also works: Bed/mulch

Plant companion: Cabbage (big, shade-making leaves)

Why: The big leaves and extended growing season of cabbage creates excellent habitat at just the right time for Chestnut beauties to properly form its symmetrical orange structure.

Best method: Mushroom bed (wood chip bed)

Plant companion: Brussels Sprouts 

Why: Blewit is a very special mushroom that appears in the wild after a frost, just when many culinary species are done down for the count. Well wouldn’t you know it, Brussels Sprouts are known to taste better after a little frost. A match made in heaven. 

Best method: Plant & Grow

Also works: Bed/mulch

Plant companion: Zucchini

Why: Blue Oysters are champions that can grow in many environments and conditions. Zucchini (might as well lump summer squash in there too) is a very hearty crop as well that provides nice broad leaves for blue oysters to keep cool and moist under. Since squash tend to vine or sprawl, they can provide protection to multiple blocks!

Best method: Plant & Grow

Plant companion: Sweet corn

Why: Reishi is a magnificent looking and powerful medicine, but slow growing. Its woody antlers explore upwards and then fan out, requiring shade and space. Corn rows should be 2-3 feet apart and can take 2-3 months to mature, making it an excellent companion.

Best method: Plant & Grow

Plant companion: Cucumbers (trellis is ideal)

Why: As with zucchini and peas, a lovely trellis of cucumbers can do so many things for a garden. One thing it does is create a large open understory and Pioppino, with their perfect hamburger bun form, are the ideal species to fill this space.

Best method: Hardwood Logs

Plant companion: Rhododendron or conifers

Why: Shiitake logs take up a nice chunk of space and do best with year-round shade. In order to achieve this, we have to look towards larger shrubs and trees that can provide this. Sometimes this is a beautiful centerpiece in the garden and sometimes it is a much larger tree (or stand of trees) on the edge of a property. And honestly, what is more beautiful than a flowering rhododendron?

Best method: Plant & Grow

Also works: Bed/mulch

Veg companion: Tomatoes

Why: Besides the fact that Italian Oysters remind me of Italian food just like tomatoes do, these species fit together perfectly. They both thrive in the heat and the tomatoes provide excellent shade. One big difference that can be seen as an advantage is speed. Tomatoes take 2-3 months to grow, while Italians can do so in 2 weeks.

Best method: Bed/mulch

Plant companion: Garlic

Why: Fall is an excellent time to plant garlic and putting down a nice thick, insulating layer of mulch can help it a great deal. Both species get established and cozy before sleeping until spring. As things warm, they wake up and begin to grow. The garlic provides shade until harvest. It’s not the shadiest plant, but Wine Cap is surprisingly sun tolerant. After harvesting the garlic, another crop can go right in!

Best method: Hardwood Logs (Totems)

Plant companion: Spicebush, Witch-Hazel or conifers

Why: Lion’s mane is a stunning and highly prized mushroom with both edible and medicinal properties. Its stark white “hair” is always striking when it fruits during cooler periods. As with all logs, consistent shade and protection from wind is the goal. Lion’s Mane performs wonderfully as a totem and these small garden shrubs or trees can help maintain the environment they thrive in.

Best method: Plant & Grow

Also works: Bed/mulch

Plant companion: Eggplant

Why: Eggplants, with their range of purples (typically) offer an excellent splash of color to any garden and the bright pink of this mushroom species adds to that vibe well. They both enjoy hot weather and the leafy eggplant does a great job providing cooler and humidified understory. 

Best method: Bed/mulch

Plant companion: Peppers

Why: Almond Agaricus is usually planted in a very rich, compost-based substrate and peppers love this extra nutrition. Peppers need heat (to make the heat) and luckily Almond feels the same way. Yet another reason these work together well is that eggplant takes 2-3 months to mature, giving Almond plenty of time with shade and minimal soil disturbance to do its thing.

Mushrooms are part of a vast kingdom of life that we interact with intimately every single day. They are in our bodies, in our food and all around us in nature. When designing a garden plan, the wise gardener seeks to create as much balance as possible to improve the yield and health of their crops. They also seek to make a space beautiful and healthier over time while utilizing space smartly and efficiently. Too often, the use of fungi is ignored or happens by accident. By utilizing companion planting with these species, you can intentionally introduce mushrooms that make the garden healthier, look incredible and are extremely nutritious food. 

Mushrooms love moisture and shade, so if you remember the conditions and plant companions that make them happen, stunning landscapes are possible. This type of gardening is largely an untapped frontier. To further understand these fascinating interactions, we encourage gardeners to experiment with different mushrooms and vegetable pairings in their own backyards, carefully observing the results. Don’t forget that using the MycoSphere is a great way to tweak conditions, protect from pests and ensure stellar yields for veggies and mushrooms. So why not get a little adventurous and introduce the amazing world of fungi to your vegetable patch?