All About Almond Agaricus

Almond Agaricus (Almonds) are sweet, fragrant summer mushrooms that can be grown outdoors in the garden. A cousin to the white button mushroom, crimini and portobella, it is much easier to grow. Just like button mushrooms, it grows in compost, but does not require pasteurization, caves or grow houses. Anyone who has a garden... flower, vegetable, shade, or container, can grow this mushroom. You don't necessarily need to plant them with vegetables or flowers, but plants help create necessary shade and harness humidity for perfect mushroom development when they are planted side by side. Grown together, there is also the mutual benefit from the CO2/O2 gas generated and exchanged by both plant and fungus, and the plants appreciate the released nutrients from the compost.

Almond agaricus mushroom with tomato

A bit about Almond Agaricus

Almonds can be cultivated commercially (and in larger scale) in beds within high tunnels and greenhouses or in areas outdoors where moisture can be added and monitored. It can grow in the shaded woods and sunny garden (best alongside big, leafy plants because of the added shade). Or, it can be grown "small scale" in window boxes and large potted plants, indoors or out. It can be planted May until early July in the north, earlier in the south, or whenever the last frost date is in your area. It is best to plant them so you can get at least 2-4 months of frost-free weather. Almond mycelium can actually survive some freezing weather, but developing baby mushrooms will not, so it's best to pack in as much growing season as possible.

Almond Cultivation in 6 Steps:

1. Gather supplies: Spawn, compost (bagged or homemade), and a watering can or hose with spray nozzle. You will also want a mulch material to help maintain adequate moisture throughout the growing medium profile. For spawn rates, see Step 4 below.

2. Site preparation and shade requirements: Choose a location for your Almond bed. The shade requirement for Almonds are related to the ability to keep the bed moist during spawn run, and humidity to encourage large and succulent mushrooms when they fruit. This can be done outdoors in a fully sunny garden if you can provide lots of mulch and frequent, light watering from a sprinkler or soaker hose over the Almond bed for its spawn run phase, and big leafy plants nearby to capture humidity for its fruiting stage. Chard, lettuces, zucchini, tomatoes and other large leafed vegetables are all suitable companions for Almonds.

3. Choose your compost and construct bed:Almonds fungally fall at the bottom in the rot chain. While mushrooms like Shiitake and Oyster must have undecomposed lignin and cellulose found in just-cut trees and other woody substrates, Almonds like rich, decomposed plant matter, further down the decay chain. As mushroom growers, we use both spent and composted Shiitake (sawdust) blocks and myceliated, composted Oyster mushroom straw; a dual "waste" substrate. It's pretty cool that you can grow two different mushrooms from the same substrate, just utilizing the food from different levels of decay. You can also use kitchen/garden waste compost, bagged composts and worm castings. We are still working with leaf-based mulch/compost but cannot yet recommend it. If you are using bulk or homemade compost, take the time to make sure the compost is moist enough, which is typically the biggest problem with using homemade compost. Use the "squeeze test": grab a handful and squeeze as hard as you can. One or two drops of water should want to drip away. The compost does not have to be perfectly crumbly and finished, but you should aim for it to get this way.
Bed construction: We have tested several bed depths and spawn rates and have determined that beds 5 inches deep inoculated at a 5% rate (5 lbs. of spawn to 100 lbs. of compost) is optimal. Make attention to bed depth your priority. Deeper beds (but not too deep for the companion plants) are easier to maintain moisture, and shallower beds are prone to excessive drying requiring more constant watering.
* Note - Choose the right companion plant: It's important to remember that compost is also considered a fertilizer and that too much might not be a good thing for some plants you may be considering to pair with your mushroom growing. Some of the nutrients are being used by the mushroom mycelium, so we honestly have never had too much leafy growth from our tomatoes even when planted into an extra thick compost bed.

4. Inoculate: After the bed is laid out (if polyculturing, we plant our transplants first and build the bed around them), it's time to inoculate. Spawn rates: You will need about 10 lbs. compost per sq. ft. of bed space that is 5 inches deep seeded (inoculated) at a rate of 1/2 lb. spawn per sq. ft. A standard garden bed 3 ft. wide and 10 ft. long requires about 15 lbs. of Almond spawn. Open the spawn bag and break off egg-sized pieces of spawn and bury on 6-8 inch centers apart in a grid pattern, making sure spawn is covered with some compost after inoculation (take a moment to enjoy the signature almond-ish fragrance of the Almond spawn). Placing the spawn at different depths is also a helpful strategy.

5. Mulch and maintain: Keeping the bed moist is perhaps the biggest challenge - you will want to keep it damp to the very top of the compost. We have used straw, paper grain sacks, shredded office paper and cardboard to try to hold in moisture without excessive watering. The best so solution so far is cardboard kept moist by a soaker hose laid on top. Daily light sprinkling underneath dry cardboard or paper is almost daily work but is also quite effective. Leafy shade from the plant canopy really helps, even when the plants are young. This year we will be installing a small irrigation system which should give us effective, automatic coverage. After 2-3 weeks, watch the beds closely. The mycelium will start to knot just prior to fruiting, indicating that mushrooms are on the way. Now is the time, as an option, to apply a casing layer (preferably just before this stage, as the compost starts to show 60 percent myceliation as shown in the photo above). A casing layer is just a nutrient poor, thin layer of a water holding material that helps increase yields. Adding this layer is OPTIONAL. You will get plenty of mushrooms without it and it is an extra step. To get the most out of your planting though, application of this layer is helpful for maintaining bed moisture and reducing the need for constant watering. We make our casing out of peat moss and adjust the pH with a little hydrated lime (found at garden centers). We often skip the casing stage because fruiting happens faster than we expected and once fruiting occurs, we feel we have missed the window of opportunity, and we are happy with the yields even without it! The mixture is spread out over the top of the bed, about 1/2" deep. Cover with mulch again and wait for the spawn to grow up through the extra layer, usually 7-10 additional days. Once the mycelium, showing at the top of the bed, starts to move from a feathery look to little tiny knots, you will know that you are just days from a mushroom harvest. Keep things moist!

6. Harvest: New flushes will continue every 2-3 weeks. The first flush will produce single, large mushrooms, with later flushes producing smaller mushrooms, but many of them. From this point, keep the bed reasonably moist until freeze up. Expect mushrooms every few weeks after a good rain or heavy sprinkling from your garden hose.

Full Instruction Sheet:
Moderate. While the method isn't necessarily difficult, maintaining the bed does take some diligence.
Casing Recipe:
3 lb. peat moss, 3 qt. water, 1 1/2 T hydrated lime (look for types with less than 1% Mg (Magnesium) like Hi-Yield). Mix well.

Hoop houses make a great way to trap heat and humidity for Almond production

plastic hoop house with greenery

Choosing a rich, fully finished compost for Almond agarics production is essential

woman leaning over a blue wheelbarrow filled with compost

Companion planting Almond Agaricus mushrooms with leafy vegetables helps trap humidity

almond agaricus mushroom growing under a tomato plant

Covering your mushroom beds with a light layer of chopped straw also helps trap humidity around forming pins

a single almond agaricus mushroom

Small "knots" of mycelium hint at forming mushrooms

pins of the almond agaricus mushroom growing in compost

A harvest of Almond Agaricus mushrooms

a cluster of almond agaricus mushrooms growing underneath a tomato plant

Medicinal benefits of Almond Agaricus:

One can't talk about the Almond without mentioning its contribution to the family medicine chest. This mushroom has the more than its share of names: Agaricus blazei, Agaricus brazilienses, The Royal Sun mushroom, and Almond Portabella, although Agaricus subrufescens is the oldest and least controversial, so we'll stick with that. Nevertheless, we believe the fruits of all mushroom cultivation should also be part of the family "pleasure" chest.