Mushroom compost for the garden has been promoted as beneficial for some time now, but it’s important to note that not every plant reaps the benefits of mushroom compost. What plants don’t like mushroom compost? Acid loving plants, for one. Is mushroom compost good for a vegetable garden? The following contains information on plants that do and don’t like mushroom compost and how to use it in your garden.
What is Mushroom Compost?
Sold packaged at garden supply centers or in bulk from mushroom growers themselves, mushroom compost is specially mixed compost most suited for commercial growing of mushrooms. It’s sold when it is “spent,” meaning after a round of mushrooms has been grown in it and it is beginning to lose some of the nutrients specific to the optimal growth of the fungi.
Just because mushroom compost is spent doesn’t mean it has no value. In fact mushroom compost is incredibly good for most but not all of the garden.
What is in mushroom compost? The recipe for mushroom compost varies depending upon the company, but it may contain wheat or rye straw, peat moss, used horse bedding straw, chicken manure, cottonseed or canola meal, the leavenings from grape pressing, soybean meal, potash, gypsum, urea, ammonium nitrate and lime.
The concoction is mixed up and then allowed to sit for about 30 days to heat up and begin the composting process. Straw provides the basis for the compost and some nourishment for beneficial bacteria and the chicken manure, while cottonseed meal and urea provide additional nutrition. The bacteria feed and multiply, raising the temp of the compost pile enough to kill any weed seeds or pathogens. The resulting compost is then ready to grow mushrooms in.
What is Mushroom Compost Good For?
Mushroom compost improves water retention, improves soil structure, has a mild nitrogen content which means it provides a slow uptake for plants but low enough to discourage weed growth, attracts earthworms, effectively insulates cooling or warming roots according to the season, and is an excellent slow release fertilizer.
What Plants Don’t Like Mushroom Compost?
Because mushroom compost is great at improving water retention, it isn't a good option for plants that don’t like “wet feet” such as succulents. This increase in water retention can also lead to rot or fungal infections.
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Mushroom compost may be alkaline due to its high content of chalk or lime. But not all mushroom compost will be alkaline, so it is best to do a pH test prior to use, especially around acidic loving plants.
Mushroom compost is also high in salt, which can be problematic for some plants such as blueberries, camellias, rhododendrons and azaleas. These soluble salts along with other nutrients in fresh mushroom compost are too concentrated to germinate seeds or plant young seedlings.
If you have mushroom compost and are unsure of its content, it's best to mix it with garden soil prior to use on young plants. Or better yet, procure your compost in the fall and allow it to sit and cure over the winter months.
Although mushroom compost attracts earthworms, at the outset it lacks beneficial microorganisms. This is because the spent product has been pasteurized prior to sale in order to kill weed seeds, pests or pathogens.
How to Use Mushroom Compost
You can either procure your mushroom compost by the bag or order it in bulk. When used after curing or when mixed with garden soil, mushroom compost can be used around perennials, trees, and shrubs. In the vegetable garden, till three inches (8 cm) of compost into the top six inches (15 cm) of dry soil.
Mushroom compost can be used in container grown plants as well, but only at the rate of 1 to 4, compost to soil.
FAQs
Mushroom compost should be used with caution due to its high soluble salt levels and alkalinity. These salt levels can kill germinating seeds, harm young seedlings, and cause damage to salt-sensitive plants, like azaleas and rhododendrons.
What plants don't like mushroom compost? ›
Mushroom compost is also high in salt, which can be problematic for some plants such as blueberries, camellias, rhododendrons and azaleas. These soluble salts along with other nutrients in fresh mushroom compost are too concentrated to germinate seeds or plant young seedlings.
What are the disadvantages of mushroom compost? ›
The Pros and Cons of Mushroom Compost
| Pros | Cons |
|---|
| High in organic matter, which increases the water-holding capacity of the soil, boosts the activity of beneficial soil microbes | High in soluble salts and other nutrients that can kill germinating seeds, harm young seedlings, and cause damage to salt-sensitive plants |
4 more rowsFeb 27, 2024
As for nutrient content, that'll vary somewhat depending on exactly what went into the compost and mushroom soil. Mushroom soil typically has more nutrient content (particularly nitrogen) than leaf compost.
What grows best in mushroom compost? ›
Mushroom compost is excellent on the vegetable garden, as vegetable crops usually grow best when th soil is not acid and where the soil is alkaline brassicas (cabbage, broccoli, cauliflower, kohlrabi, Brussels sprouts and kale) are less likely to be infected by clubroot disease.
Do marigolds like mushroom compost? ›
In trials spanning 2.5 years, SMC was effectively used as a substrate in the production of marigold (Tagetes patula) 'Yellow Girl'.
Will mushroom compost burn my plants? ›
In other words, using too much mushroom compost in your garden can possibly “burn” plants. The safest way to use mushroom compost this time of year is to use it sparingly. To be perfectly safe, mix mushroom compost with garden soil before using it on young plants.
Can you plant tomatoes directly into mushroom compost? ›
Q: Can I plant directly into mushroom compost? A: It depends on what you are planting. Direct seeding of wildflowers, turfgrass, radish, carrots, herbs, lettuce are known to do quite well. Transplanting of hops, tomatoes, peppers, kohlrabi, cucumber plants have also been possible.
Do you mix mushroom compost with soil? ›
The best approach would be to apply mushroom compost uniformly and evenly at a one to three inch thickness (three to nine cubic yards per 1,000 square feet) on the surface of the intended site, and then incorporate into the existing soil below.
Is mushroom compost good for potting mix? ›
Use mushroom compost to improve your soil so that it provides the air, moisture and nutrients that plants need to grow well. Mushroom compost is high in organic matter, which enhances all soils, from heavy clay to light, free draining sand.
Applying Mushroom Soil to the Garden
For convenience I'm usually not able to add mushroom compost until early spring, much closer to the planting season than I would prefer, but I haven't noted any problems with over fertilization or burning of the plants or seedlings.
What is better, cow manure or mushroom compost? ›
Richer source of organic nutrients: manure is a source of many nutrients such as nitrogen, phosphorus, and potassium. In fact, most manures may contain slightly more of these three nutrients than mushroom manure.
What is the best compost for vegetable gardens? ›
Loam Based Compost
Loam-based compost is a combination of soil, sand, and clay that has been decomposed and processed to create a deep, rich product that is ideal for growing vegetables. Loam-based compost can be purchased commercially or created at home using a simple composting bin.
Do peppers like mushroom compost? ›
Q: Can I plant directly into mushroom compost? A: It depends on what you are planting. Direct seeding of wildflowers, turfgrass, radish, carrots, herbs, lettuce are known to do quite well. Transplanting of hops, tomatoes, peppers, kohlrabi, cucumber plants have also been possible.
Is mushroom compost OK for tomatoes? ›
Certain vegetables particularly thrive in mushroom compost due to its rich nutrient content. These include tomatoes, zucchinis, pumpkins, and root vegetables such as carrots and radishes. The nutrients in mushroom compost can help stimulate growth, increase yield, and enhance the taste of your homegrown produce.
Do hydrangeas like mushroom compost? ›
Ideally if you have composted horse manure, cow manure, any kind of organic matter like mushroom compost, it makes no difference. Use it. Then cover it up with two inches of mulch or something to preserve moisture.
What plants do not like fertilizer? ›
Perennials that require no fertilizer: Included are ornamental grasses, false indigo, ground covers, butterfly weed, bee balm, coneflowers, black-eyed Susans, sea holly, dianthus, asters and veronica. summer: Use a quick release food in summer, instead of a slow release food.
