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Humidifying FAQ

Humidifying FAQ



What are the benefits of using an air pump?

It allows for better humidification in conjunction with perlite, geolite and lava rocks. It also provides automatic aeration pushing the C02 up and out the FAE holes in the PMP lid, so there is no need for misting or fanning!

What size air pump do I need to use?

The following chart shows how much air needs to be pumped out to get to the 2-3 air exchanges per hour rate sugged in the Poor Man's Pod (PMP) tek for a container of a given size. Values are in cubic centimeters per minute and liters per hour and 2-3 air exchanges per hour.

[ccm/min]
Output
[l/h]
10 Gallon1297-194578-117
20 Gallon2593-3890156-233
30 Gallon3890-5835234-350
40 Gallon5188-7780312-468
50 Gallon6485-9725390-585

Where can I acquire an air pump

Most pet stores/large chain stores such as Walmart will stock air pumps.

How should I wire the air pump?

Place two bubble wands in the bottom of your fruiting chamber and connect the tubing from air pump to the tubing and plug your pump in.

Help? what do I do with this noisy air stone/pump?

Noise can come from either the pump or the air stone.

Pump Noise

Aquarium air pumps use a vibrating bellows to pump air out the tube. Since the entire unit vibrates, if it's placed on something that resonates (hollow box, shelf, desk, floor, etc.) then the noise will be transmitted to that surface.

It's possible to suspend an air pump inside a boxlike frame using rubber bands, which will result in minimal sound transfer. This same technique is used by many people with water pumps in water cooled computers, to reduce the hum of the water pump.

Air stone Noise

If you have noise from the air stone, it could be one of two things:

  • Too much pressure through air stone
  • Clogged air stone.

If a new/cleaned air stone does not solve the problem you can do one of these:

  • Install a valve to regulate flow to the air stone.
  • Split the flow and install another air stone (could be constructive for larger terrariums where you might get clumps of high humidity around the stone).
  • Buy a bubble wand (better than an air stone).

What are the benefits of using a humidifier?

The benefits of using a humidifier are that you will have to fan and spray your fruiting chamber much less.. or not at all. Oftentimes a humidifier setup will be completely automated or low maintenance.. i.e - once you reach a certain stage.. you may not have to do anything besides add water to the humidifier and pick mushrooms. It often eliminates the need for fanning or misting.

A cool mist humidifier provides almost ideal humidity levels for casings, and more importantly, constant gas exchange. Unless you have a very large terrarium, a cool mist is usually enough to provide adequate humidity levels.

If you are going the humidifier route is recommended that you invest in a quality hydrometer to monitor the humidity levels.

What are the different type of humidifiers?

Impeller
In this humidifier, a rotating disc flings water at a comb-like diffuser. The diffuser breaks the water into fine droplets that float into the air. You normally see these droplets as a cool fog exiting the humidifier.

Ultrasonic
An ultrasonic humidifier uses a metal diaphragm vibrating at an ultrasonic frequency, much like the element in a high-frequency speaker, to create water droplets. An ultrasonic humidifier is usually silent, and also produces a cool fog.

Wick/Evaporative System
The wick system uses a paper, cloth or foam wick or sheet to draw water out of the reservoir. A fan blowing over the wick lets the air absorb moisture. The higher the relative humidity, the harder it is to evaporate water from the filter, which is why this type of humidifier is self-regulating -- as humidity increases, the humidifier's water-vapor output naturally decreases.

Steam
Often referred to as a "vaporizer," a steam humidifier boils water and releases the warm steam into the room

Which is the right humidifier to use?

The ideal humidifier for mushroom cultivation is arguably the cool mist (impeller type) humidifier. They can usually be piped straight into your fruiting chamber and run 24/7 without problem. These provide a constant supply of fresh humid air and no other air exchange is usually necessary (depending on size of container, leaks, etc..) If additional humidity is required (such as if you live in a dry climate), you may combine with an ultrasonic on a timer, add a layer or tray of wet perlite, or hand mist.

Cool mist is good for mild humidity and constant air exchange
Ultrasonic is good for boosting humidity quickly

What about Ultrasonic Humidifiers?

Ultrasonics may also be used.. they pump out a lot of mist in a short amount of time, and generally require additional air exchange. Ultrasonics can easily over-saturate casings (even cakes), so a timer is needed to run the ultrasonic 5-15 minutes every hour.. or a humidistat to control the humidity. When using an ultrasonic one must consider air exchange and maybe even a more constant humidity source, whether it be through fanning, perlite, exhaust holes, air pump, or combined with a cool mist humidifier.

If you run an ultrasonic humidifier than you may want to consider purchasing a humidity controller, which keeps the humidity between your desired levels.

Can I use a warm mist humidifier?

In general, no.. warm mists are to be avoided.
However there is the exception of using a warm mist as humidification in cold climates in the winter months.. when you want to keep temps up and stable because cold air has trouble holding humidity. But fruiting conditions are about the same as a comfortable room temperature for humans.. so there is little reason to have mushrooms in the cold indoors.

Warm water is also a breeding ground for bacteria.

What are some good brands and where can I get them?

Vicks, Sunbeam or Kaz Cool Mist humidifiers are reliable...found at any pharmacy/drugstore...CVS, Eckerds, etc.

How do I rig up a cool mist system?

There are a number of ways. You have to send piping from the humidifier output into the fruiting chamber. This is the tek I have used several time with good success:

1. Cover & seal the original humidity output hole (layers of duct tape work..)
2. Drill a new hole close to the original with a 5/8" drill bit
3. Acquire a section of garden hose (3-5') and wedge it into that hole, it may take a little work (rub some vegetable oil around it) but it will go in. You *may* need to drill the hole out a LITTLE BIT bigger.. but make sure you get a tight fit around the garden hose.. you need a tight seal. Once you have it in, seal around the crack with some waterproof silicone or epoxy. Allow to dry.
4. Run the other end of your garden hose into terrarium. For best results have the line feeding into the fruiting container at a high point. If you are trying to make it professional, you can use a garden hose male adapter piece to run the line into the chamber. Make sure you don't have air leaks from the humidifier into the terrarium. Also ensure that the hose does not 'dip' or have any low points where water can collect. Make sure everything has a tight seal.
5. Drill a few small (1/4-1/8") drainage holes in the sides of your fruiting chamber 2-3" from the bottom. These are for air exchange to exhaust CO2 gases, which are heavier than air, thus sink to the bottom.. You will want to stuff the holes tightly with polyfil or cover with a scrap piece of micron filter.

Of course you may use other piping/connection methods. Be as constructive as you like.

Where should holes be drilled in the Cool mist, if Pipes of some sort are going to be ran out from it into a Martha set up, For example?

In the original output hole or as close to it as possible. If a new hole is needed, seal the original hole and drill your new hole close to it. Make sure your hole is drilled into the reservoir where the mist will still escape. In some humidifiers (ultrasonics, wick..) there is no room to drill any new holes so you will need to be creative with your piping.

Is one cool mist usually enough to properly humidify a Martha set up or should it be used in conjunction with an Ultrasonic?

This depends on several variables.. such as atmospheric humidity, casing depths, chamber size etc.. As such, experimentation is needed to determine your personal needs and if an ultrasonic is needed or not.

Casings themselves evaporate a good amount of moisture.. a cool mist running 24/7 and some hand misting once or twice a day is usually sufficient for proper humidity levels in a medium "tent" setup.

If you need additional humidity and decide to add an ultrasonic in conjunction with the cool mist.. add a humidistat, or put it on a timer to run 5-15 minutes every hour. More than that will easily oversaturate your environment. The ideal solution for this setup would be a cool mist running 24/7 and an ultrasonic on a humidity controller.

What can I do to ensure the water in my humidifier is clean and minimize contaminants?

  • Use distilled, bottled, filtered, or even (cooled) boiled water. Tap water is generally to be avoided.
  • H2O2 (Hydrogen Peroxide) should be added to the water at about 10202 to 90ater.
  • A small amount of iodine can also be safely added (1-2 drops per gallon)
  • Make sure your humidifier air intake has a clean filter on it. If it did not come with one, tape a HEPA or micron filter over it.
  • Practice general sterile procedure and keep yourself and your grow room clean. Run a HEPA filter in the room.

What are the ideal humidity levels for cakes and casings?

For cakes: 95-100elative humidity
For casings: 92h dropped to as low as 82h during fruiting.

What is the deal with positive pressure?

Positive pressure is basically when you have more air blowing into your terrarium than can escape at once.. creating a positive airflow.. constantly "pushing" air out. Ideally this is achieved by a tightly sealed chamber and the CO2 exhaust holes near the bottom, collectively smaller than the diameter of the humidifier hose coming in. This creates a positive air pressure that helps prevent contaminants  from entering. Although this is not necessary, it gives some growers peace of mind that their fruiting chambers are less susceptible to contamination.

I'm having problems maintaining the proper humidity levels.. help!

With humidifiers it may take a little trial & error and experimentation to find the optimum humidity levels for your setup. It may take a little tweaking on your part, but isn't that half the fun?

First.. do you have a calibrated hydrometer? This is an important tool for monitoring humidity levels.

If you live in a dry climate or have a large growing chamber, additional humidification may be required. If you determine this to be the case, you have several options:

  • Check your humidifier line and terrarium for air leaks. Make sure your humidifier is working properly.
  • Lightly hand mist casings and chamber once or several times a day
  • Add an additional humidifier (ultrasonic & cool mist is a good combo for large units) Make sure to run the ultrasonic on a timer and tweak the settings until you find the right timing for optimum humidity.
  • Add a layer or tray of wet perlite into the growing chamber (boosts humidity)
  • Add an air bubbler blowing into a cup of water with some H202 added. (Boosts humidity 10-15 nd additional air exchange)

If your humidity is too high.. you may lower it by

  • Fanning more frequently
  • Cutting down the time and frequency the humidifier(s) are on
  • Misting less frequently

What is perlite?

Perlite is made of small pieces of extremely porous volcanic rock. If you look at is closely (microscopically) you'll see that it looks like swiss cheese with (relatively) huge holes. When water is added, it is wicked into these pores of the perlite. This porous structure then serves to slowly evaporate the water back into the air.

For more information on perlite and how to buy and use it:
http://www.shroomery.org/39/Perlite-Humidification-FAQ

Can I substitute perlite with anything else?

Yes!Grow Rocks, geolite lava rocks....

How does Perlite humidification work?

 Perlite wicks water into the air rather than absorbing it like vermiculite, making it perfect for humidification. Add 1.5" of water to your fruiting chamber and place 2.5" to 3" of perlite in.You may have to mist walls of fruiting chamber every once in a while after fanning to help get the humidity back up.

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