Introduction: (Initial Observation)
Mushroom production is now a widely distributed and profitable industry with more than $900,000,000.00 annual sales by about 275 mushroom farms.
As with every other industry, mushroom growers are concerned about the production rate and do every possible effort to increase their productivity.
Proper temperature, proper moisture, and proper lighting are some of the environmental factors that may affect the production rate of mushroom.
In this project we study the effect of one specific factor (light, temperature, or moisture) on mushroom growth.
Find out about mushroom growth. Read books, magazines or ask professionals who might know in order to learn about the mushroom and factors affecting mushroom growth. Keep track of where you got your information from.
Following are samples of information that you may find:
There are many different types of mushrooms produced in the world, but the most widely produced mushroom is known as white button mushroom with a scientific name of Agaricus bisporus.
Successful mushroom growing involves overcoming difficulties such as temperature and humidity control, pest control and compost preparation. The amateur mushroom grower should recognize that most basements do not provide ideal conditions for good growth.
Mushroom production is a difficult task at the best of times. This publication is intended to provide useful tips in order to increase the rate of success of growing mushrooms.
For the amateur, mushrooms are usually planted in the fall and the best location is the cellar, basement or a barn or any tight, light-proof, well ventilated and insulated building. The following conditions should be met:
Air temperatures controlled between 13°C and 21°C.
Relative humidities between 80-95 %.
A corner of the basement can be partitioned off by the use of a polyethylene divider. This will help to maintain proper humidity levels. A plastic hood placed over the growing bed is a second alternative. Do not place beds where direct sunlight will fall on them. Ventilation is useful to remove offensive odors. Where temperatures cannot be maintained, supplementary heat is necessary.
Mushroom beds are usually 120-150 cm wide, 15-20 cm deep and as long as you wish. Boards that form the bottom should not be over 15-20 cm wide, leaving 2 cm to 4 cm cracks between them for ventilation. Several tiers can be made approximately 60 cm apart. Production in plastic bag beds is also used commercially especially in Europe.
The growing medium for mushrooms is a compost which traditionally has been made from horse manure, hay, poultry manure, brewer’s grain, gypsum and commercial fertilizers, including ammonium nitrate.
A suggested formula for trial use is as follows:
horse manure (85%) .75m³
hay (10%) .5-1 bale
poultry manure (5%) 18 L
gypsum 4.5 kg
ammonium nitrate .45 kg
This formula will supply sufficient compost to fill a growing bed with the following dimensions: 300 cm long, 120 cm wide and 15 cm deep, or .57m³. A growing bed 20 cm deep is more satisfactory.
To prepare the compost, start with a layer of manure on the bottom and alternate with a layer of hay, poultry manure and fertilizer materials. If possible, the horse manure should be piled under cover and and the pile should be square and the top level. Wet the pile thoroughly during layering and throughout the 12-14 day composting period. Turn the pile on the third day, mixing the ingredients thoroughly, add water to run-off and repeat the turning process on the 6th, 9th and 12th days.
If there is enough moisture, oxygen and nitrogen, the temperatures within the pile should rise to 60°C-66°C. At the end of the composting period, the compost should be dark brown, piliable and lumps should break apart easily. The compost is now ready for the beds. Hobby mushrooms growers report some success using straight, fresh horse manure obtained from horse stables with no other additives. The horse manure is then composted for 10-14 days, steam pasteurized for 30 minutes at an estimated 71°C, allowed to aerate sufficiently to remove all traces of ammonia odor and placed into beds. Steam pasteurization is required for the control of insects and diseases that are present in the compost.
Production Steps – Spawning
Allow the compost to remain in the beds until the temperature of the compost drops to 21-27°C before applying the spawn. Ammonia odor in the beds will usually kill the spawn. The compost bed should be mounded up firm, but not packed. Spawn should be broadcast over the surface of the bed and mixed thoroughly into the compost. Apply the spawn at the rate recommended by the supplier. Spawn is available in small packages from seed companies and garden supply centers. Maintain the bed temperature at 21°C-25°C for 1 week then lower the temperature to 15°C-18°C for the remainder of the production period. Spawn will be killed at 35°C. Examine the spawn run in the bed after 2 to 3 week. Casing should be applied when the white cottony growth of the fungus has reached the top of the bed. Remember to keep the compost moist at all times. It is good to cover the bed surface with newspaper or plastic. Keep the newspaper wet. Very little fresh air is required during the spawn run.
The two most common pests that are likely to occur are:
Fungus gnat (fly) larvae, and
Fungus gnat larvae may be controlled by hanging insecticide strips. Several insecticides may be used as thermal fogs. For details consult your provincial mushroom specialist. Fungicides may be used for disease control. Apply only if disease problems have been encountered and only after casing. If necessary, a second application can be made up to the first pinning. Consult label recommendations for days to harvest. Use a small pressurized sprayer or a watering can with a fine nozzle. (Yellow sticky traps can be used to monitor fly levels.)
A convenient casing material contains equal parts by weight of sphagnum peat moss and calcitic limestone. Prewetting of the casing material is advisable. Commercially prepared casing material to which lime must be added is available from Annapolis Valley Peat, Berwick N.S. The moist casing layer is placed over the surface of the compost bed to a depth of 2-4 cm.
First mushrooms should appear 3-4 weeks after casing. Regular watering to keep the casing soil moist will encourage mushroom growth and help to keep the humidity high.
Sprinkle frequently with warm water but do not overwater. Good ventilation is important when the pins, (small mushrooms) begin to develop. A mushroom is ready to be picked when the diameter of the cap is equal to the length of the stem and preferably before the veil under the cap stretches and opens. Mushrooms are twisted out rather than pulled. Good commercial yields often reach 1.4 kg per m².
What do you want to find out? Write a statement that describes what you want to do. Use your observations and questions to write the statement.
The purpose of this project is to study the effect of light on mushroom growth.
Alternatively you may choose any of the following purposes:
The purpose of this project is to study the effect of moisture on mushroom growth.
The purpose of this project is to study the effect of temperature on mushroom growth.
When you think you know what variables may be involved, think about ways to change one at a time. If you change more than one at a time, you will not know what variable is causing your observation. Sometimes variables are linked and work together to cause something. At first, try to choose variables that you think act independently of each other.
Independent variable (also known as manipulated variable) is the amount of light. Possible values are dark, room light, room light plus additional artificial light.
Dependent variable (also known as responding variable) is the growth rate.
Controlled variables are the temperature and moisture. (Grow all samples in the same light and moisture conditions.)
Constants are the type of mushroom and growth media (compost, saw dust, etc.)
Based on your gathered information, make an educated guess about what types of things affect the system you are working with. Identifying variables is necessary before you can make a hypothesis.
This is a sample hypothesis:
Since mushroom is not a green plant, it does not require any light. As a result I hypothesize that light has no effect on the growth of mushroom.
This is another sample hypothesis:
Mushroom will grow at a lower rate when exposed to light. My hypothesis is based on my gathered information about fungi (such as mold, mushroom, lichens). I have read that mold grows in the dark, so I expect all other fungi do the same.
And one more hypothesis:
Mushroom will grow best in light. Dark and moist environment may cause growth of mold and reduce the nutrients needed for mushroom growth.
Note that you may come up with a different hypothesis or a variation of the above sample hypotheses.
Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”
Experiment 1: Grow Mushroom using a kit
Introduction: In order to find out how light affects the development and growth of a mushroom, we need to grow three groups of mushrooms in three different light conditions. All other conditions such as temperature and moisture must remain the same, so we will know that the light has been the only factor that may have caused the difference in growth rate. A mushroom kit is a good place to start. The following experiment is recommended if you can purchase a mushroom kit. Mushroom kits may be available in your local nursery (plant store). You may also find mushroom kits online. Simply search for mushroom kit or mushroom growth kit.
- Get six identical mushroom kits (Or get one kit and break it down to six identical pieces in a clean room). You will use two kits for each light condition.
- Place all six kits in the same room so they will have the same temperature. Cover all six kits with clear plastic to preserve moisture. (Leave some openings for air to flow).
- Cover two of the kits with aluminum foil or a carton box (in addition to plastic) to keep them dark.
- The second pair will use the ambient light.
- Light up a fluorescent desk lamp above the pair that is going to get more light. Use a cardboard if necessary to protect the others from getting light from the desk lamp.
- Inspect the kits every day and spray them with water to keep them moist.
- Record your observations every day. In your observation include the number of pins or visible mushrooms and the size of the largest mushroom (diameter of the cap).
- After 30 days (or whatever time recommended by mushroom manufacturer) remove all mushrooms of each group and weight them separately. Record your observations in a table like this.
- Record your results in a table like this:
|Date||Dark||Room light||Fluorescent light|
|Pins||Max cap||Pins||Max cap||Pins||Max cap|
|Final Total Weight|
Experiment 2: Find Mushroom in the nature
Like all other organisms, mushrooms grow where the conditions are favorable. This fact can be used to identify the conditions favorable for mushroom growth. If you live close to woods or a natural park where mushrooms grow, this can be a fun experiment.
Visit a place where natural wild mushroom grows.
Search for mushroom. Finding and picking mushroom is a hobby for some people; however, wild mushrooms may be poisonous. Do not pick or taste mushrooms that you find.
Whenever you find a mushroom, record the temperature, light condition, soil moisture and the type of substrate.
Record your data in a table and use it for analysis and reporting. Your data table can look like this:
|Sample #||Date / Time||Light condition||Moisture||Temperature||Substrate|
If you have any type of light meter, use that to determine the amount of light; otherwise, simply write a number between 0 and 10. Smallest number is 0 for dark, largest number is 10 for full daylight with no shade.
To determine moisture of the soil, you can use a soil moisture sensor available from garden suppliers and hardware stores. You may also estimate the moisture by touching the soil and write a number such as 0 for dry, 2 for very low moisture, 5 for medium moisture, 7 for high moisture and 10 for wet.
Substrate type can be animal droppings, dead tree, live tree, soil, sand,…
Experiment 3: Mushroom Mycelia growth
Gathered information indicates that entire mushroom is composed of compressed mycelia and a culture can be obtained from any part of the mushroom. In the following experiment you grow mushroom mycelia on a semi-solid medium such as agar using a tissue culture.
Agar or gelatin plates
cotton swab (such as q-tips)
vegetables (such as carrots, green pepper, squash, potato, etc.)
- Prepare four agar or gelatin plates. Commercial agar plates such as Sabaroud Dextrose agar plates can be used for fungi growth experiments. Homemade gelatin medium will also work as well.
- Label the bottom of two plates “dark” and two other plates “light”
- Wash a mushroom and dry it. Pull it a part to break it and reveal inside of the mushroom fruit. Use a sterile sharp object to remove a small piece of mushroom and place it on each plate.
- keep the plates at room temperature. next to a window. Cover two of the plates with a carton box to keep them in the dark
- observe the plates every day for 7 days and record the growth of mycelia in each plate. (How many millimeters around the mushroom piece)
Prepare homemade gelatin plates as follows:
pour into sterile disposable petri dishes or muffin cup liners and store in plastic sandwich bags.
For homemade medium you will need:
beef bouillon granules
foil muffin cups
In a saucepan, mix 4 envelops of plain gelatin with 4 cups cold water, 8 tsp. sugar and 4 tsp. bouillon granules (or 4 bouillon cubes).
Bring slowly to a boil, stirring constantly.
Cool slightly and fill either sterile disposable petri dishes or foil muffin cup liners in muffin pans for support, about 1/3 full with the hot gelatin solution.
Cool until the gelatin is solid. Remove foil muffin cup liners from muffin pan and store in plastic zip-lock bags in the refrigerator. Do not touch the surface of the gelatin. Makes 25-30 cups.
- A nutrient agar or gelatin plate that you use in this experiment is good for the growth of many different organisms including bacteria. It is very important to use a sterile tool to transfer a piece of mushroom to prevent cross contamination and growth of other bacteria.
- If you use a knife to cut the mushroom, the knife blade transfers surface bacteria to the inside flesh of mushroom. That is why you pull it apart and break it to access the inner flesh.
- The size of the mushroom sample that you use, can be as small as a dot.
- To sterile a sharp tool, keep it on the flame for a few seconds or insert it in methyl alcohol for a few seconds.
Materials and Equipment:
List of material may be extracted from the experiment section.
Results of Experiment (Observation):
Experiments are often done in series. A series of experiments can be done by changing one variable a different amount each time. A series of experiments is made up of separate experimental “runs.” During each run you make a measurement of how much the variable affected the system under study. For each run, a different amount of change in the variable is used. This produces a different amount of response in the system. You measure this response, or record data, in a table for this purpose. This is considered “raw data” since it has not been processed or interpreted yet. When raw data gets processed mathematically, for example, it becomes results.
If you do any calculations in your project, make sure you write your calculations in this part of your report.
Summary of Results:
Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during experiments.
It is from calculations using recorded data that tables and graphs are made. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Based on these trends, we can draw conclusions about the system under study. These conclusions help us confirm or deny our original hypothesis. Often, mathematical equations can be made from graphs. These equations allow us to predict how a change will affect the system without the need to do additional experiments. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. At this level, science becomes even more interesting and powerful.
Using the trends in your experimental data and your experimental observations, try to answer your original questions. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.
Related Questions & Answers:
What you have learned may allow you to answer other questions. Many questions are related. Several new questions may have occurred to you while doing experiments. You may now be able to understand or verify things that you discovered when gathering information for the project. Questions lead to more questions, which lead to additional hypothesis that need to be tested.
If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.
If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.
Visit your local library and find books about mushroom. List such books in addition to the Internet resources you use as your references or bibliography.
Following is a list of web resources.
Major Edible Mushroom Species
The Micological Society of America
Mushroom Kits for home growing
I grow Mushrooms
Small Scale Mushroom Production
Mushroom Production Figures
Irish Mushroom Production
The Future of Mushroom Production in the United States