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How To Grow Baby Bella Mushrooms in 12 Simple Steps

Baby Bella mushrooms (also known as Crimini mushrooms) are the pre-mature form of Portobello Mushrooms. Baby Bellas are rich in nutrients and are great for health due to various minerals, vitamins, calcium, selenium and proteins. 

How To Grow Baby Bella Mushrooms
Baby Bella Mushroom Growing Kit via Amazon

A Guide on How To Grow Baby Bella Mushrooms

There are several ways to grow Baby Belle mushrooms at home. The method described below uses cardboard paper tubes filled with a properly prepared substrate in small containers or cups.

You can also use jars or other water/liquid-tight containers. Let’s see how to grow Baby Bella mushrooms step by step.

1. To grow baby bell mushrooms, you need to obtain cardboard paper tubes and containers to put them in – the number of containers depends on how much substrate you’ll be able to make.

If you can prepare more substrate, use bigger containers; otherwise, use smaller ones.

Make sure the container is water/liquid-tight (for example, use plastic containers/cups instead of glass ones, since the mushrooms need to be fully covered with substrate until it’s colonized).

2. Prepare your stuff to make a substrate for baby bell mushrooms.

Substrate Preparation

  • Take 10 cups (~1 liter) of rye or wheat berries (or a mixture of both). If you cannot get either of those, you can use whole brown rice.
  • Put the rye or wheat berries in a large pot and cover with cold water at least 2 inches above the substrate level. Bring this to a boil and cook for about 15 minutes – do not drain yet!
  • Add approximately 1 tablespoon of gypsum and stir thoroughly (the heat released by boiling the substrate will help it mix better).
  • Cover and let drain using a colander. Let stand for about 30 minutes – do not rush this step since you need to make sure all of the water has drained away, or your substrate will be too wet (if you like, you can put some weight on top of the substrate to help the water out).
  • Pre-heat oven to 400 F (~200 C).
  • Put your rye or wheat berries in a large baking pan (or any other dish that can fit inside your oven) and bake for about an hour (stirring every 15 minutes), then remove from the oven. Make sure you keep an eye on it while baking – some ovens are less accurate than others, so check for dryness/done-ness often.
  • Fill the pot with substrate back to the level of ~2 inches above the substrate. Let cool to room temperature. After that, put your container in a place where it can receive indirect sunlight or incandescent light only (no fluorescent lights, no direct sunlight).
  • Mix the substrate you just prepared with another one. The nutrient content of the substrate is important for the healthy development of mushroom mycelium and growth – if it’s not right, your mushrooms will be weak or might not grow at all! You can vary the quantity of rye/wheat or brown rice if you want to change the nutrient content of substrate for your baby bell mushrooms.
  • The mixture should be about 60% rye/wheat berries and 40% whole brown rice by weight (or any other combination – at least 60% grains and 40% vegetables, such as potatoes). Mix all ingredients in a large container/bowl.

3. Prepare your jars or other small containers filled with a substrate for baby bell mushrooms by filling each one to the top with the mixture of rye/wheat and brown rice.

This should leave you with about 2 inches of space at the top, so if you have a jar, cover it tightly with plastic wrap – if you are using some other type of container, make sure it is water/liquid-tight (for example, use plastic containers instead of glass ones).

4. Clean the mushrooms by removing any over-mature caps and soft or discolored parts on their stems; rinse with tap water if needed.

5. Cut off the stipe/stem just above the substrate level. If you leave too much on top, your mushrooms will have problems developing properly compared to those cut off right above substrate level.

6. Put your mushroom stipes into a pre-heated oven at 400 F (~200 C) for about 10 minutes – this step is called ‘drying.’

Drying the mushrooms at high heat for about 10 minutes before putting them into substrate speeds up primordia development. It would be best to dry your stipes to kill any insect larvae/pupae/eggs on them.

7. Place your pre-dried mushroom stipes into substrate-filled jars or other containers – always make sure that the length of your mushroom stipes is shorter than the depth of substrate inside the jar/container so that they can receive enough oxygen!

8. Cut away any parts of the cap which are discolored, soft, or over-mature – do not let weak mushrooms develop. If you end up with more than 1 mushroom per jar, cut off any parts of caps damaged by insects or other contamination (use a clean disposable sanitized knife).

9. Fill the holes on top of the substrate and around stipes with dry vermiculite (you can find this at any gardening store) to prevent contaminants from entering the jars – do not pack it tightly; fill in the gaps between substrate and lid/top of the jar.

10. Cover holes with tin foil or another type of coverage that will allow light to pass through but protect your inoculate from contamination (i.e., sunlight). If you see condensation forming on your jar/container – that’s a good sign, as it means that you have proper humidity inside.

11. Put substrate jars into a dark place for about 2 weeks (the ideal temperature is 70 F or 20 C). I recommend using some heating pad for creating a stable temperature around jars (~70 F or 20 C) – you can buy heating pads or make one yourself (google it, there are some good DIY instructions online).

12. After 2 weeks of incubation, baby bell mushroom mycelium should be well developed and ready to inoculate your outdoor patch/mini-farm! Don’t get frustrated if your jars don’t look like they are 100% colonized after 2 weeks – some jars can take up to 3 weeks of incubation!

How To Grow Baby Bella Mushrooms: Transplanting Guide

1. Find a good spot in your yard/garden where you want to start your mini-farm. It is recommended to clear the ground beforehand if possible, removing roots and stones that might be too heavy for baby bell mushroom mycelium later on.

2. Dig a 4-5 inches (~10 cm) deep and wide hole, and fill it with loose soil from the ground you have just cleared.

This step is called ‘back-building’ – soil from already cultivated land has been deprived of some essential nutrients by previous crops, so it might be wise to use soil from your backyard instead of buying it from a gardening store if you can.

3. Dig out about 2 inches (5 cm) worth of substrate from the jar and mix it with the soil in the hole – if possible, try to evenly spread this mixture around so that the surface level of your mini-farm is even on all sides.

4. You can then put some loose mulch or leaves on top of the mini-farm to help conserve humidity in soil – if you have access to horse manure, you can also mix it with the substrate in the hole.

You can either cover your mini-farm with a waterproof barrier (e.g., plastic sheeting) or leave it open for air to circulate in.

If you choose to cover it with plastic, make sure that there is still some space for air to circulate (leave some parts where the barrier isn’t touching soil uncovered). At this point, your mini-farm is ready to inoculate!

5. Put on your gloves and protective goggles/mask – although baby bell mushroom mycelium is not poisonous, it is better to be safe than sorry!

6. Use a disposable sanitized knife/scraper to open up the holes in your substrate jar and take out the contents of the jar – make sure that you do not touch or move anything inside your mini-farm apart from mushrooms themselves!

7. Place mycelium blocks (contents of your substrate jar, with living white mycelium on top) around the surface of your mini-farm (at least 3 inches or 8 cm away from each other!).

So that they are touching soil. If you want to get fancy, you can start making single holes in your mini-farm and place a block in each hole at a slightly different depth.

8. Keep your mini-farm moist for about 4 months, and you should start seeing baby bell mushrooms sprouting from it! Make sure to turn over the soil every once in a while not to dry out or get compacted – this will improve airflow around substrate blocks/mushrooms. 

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Final Remarks

Although the procedure seems quite extensive, it is a rewarding experience once you harvest mushrooms. Now that you know how to grow baby Bella mushrooms, you can enjoy these delightful mushrooms at home for months!