Grow Tent Guide.

Using our grow tents

We have different kinds of grow tents, and they all try to achieve the same end result:

• Keep the humidity high
• Provide the FAE (fresh air exchange) that you need

The reason FAE matters is CO2. Mushrooms breathe out CO2 the same as we do, and in a sealed bag or tub it builds up around them - nearly every problem you'll see in a tent comes back to that: fuzzy bases, long thin stalks, small caps. FAE is about getting the CO2 out while keeping the humidity in. The other half of it is that the surface of your substrate wants to be damp but slowly drying, a bit of evaporation is what tells the mycelium to pin. Sealed up air-tight will suffocate your mycelium.

Some of our tents are the old-style, which include white filters already embedded into the tents - the issue with these tents is that they aren't truly humidity grow tents, they are substrate bags (as in, you mix spawn and substrate in them to colonise) - they do have a higher air flow while keeping humidity in, but just not quite enough for brilliant flushes without doing some mods along the way (cutting extra FAE holes). Our cheapest kits still use these bags, and for small grows it can be fine (like the EZPZ or even the MycoPots kits).

Unmodified grow tent ftw

What we have now for all of the bigger grow kits is a larger tent with no filters embedded in it, it doesn't even have any holes. And with them, we include special filter material if you want to use it.

There are many ways to use this fruiting tent, some folk will just fold the top of the tent over at an angle so there is a "chimney" on the corner edge for FAE - you can even position a bit of filter material in there to keep it open and then paper clip (included too) or tape the rest of the tent shut. Maybe you want to create two chimneys at either side - try what you want.

This filter is superior to micropore or polyfill stuffing because it won't clog up when it gets damp and reduce the airflow. The same cannot be said about those other materials which are popular - after a few days we've found them to become soaking and reducing air exchange, our filter is made for a soaking wet tent.

We first learned about top FAE in monotub grows where there aren't any drilled holes anywhere on the tub (Bod's unmodified tub tek on the Shroomery, going since 2015) with the only airflow getting in coming from the lid being positioned at a slight angle so each corner is a little bit open to the world... Some seriously impressive flushes with mushrooms as long as my forearm. The same technique can be adapted to our grow tents.

So if you have the idea that all FAE has to come from holes in the top and bottom, get that out of your mind because it's simply untrue. We used to think the same. We've spent half of this hobby being told something from confident know-it-alls, to then having to unlearn it because it was just not true. So, back to the point - airflow coming from an unmodified tent via the top can absolutely work.

What will make a difference though is consistency and watching your mushrooms. They are always trying to communicate with you. Tmethyl's How it should & shouldn't look guide on the Shroomery has photos of all of it: fuzzy bases, tall thin stems with small caps, aerial mycelium, all low FAE. Does it look dry in there? Well, maybe the water in the perlite needs topping up. Maybe the FAE is too much. If humidity is being lost, make the stuffing a little tighter. ComebackKid's surface moisture thread on the Shroomery explains the wet to dry cycle you're after better than we can. Thin mushroom stalks with small caps? That's CO2 again, so more FAE first - and then check your temperature too, if it's too high, bring it down.

Another thing. FAE will be different depending on the room you are growing in. If you are in and out of the room all the time, then there's going to be more air currents. If there's a fan, then the same. If you hardly go into the room, hardly any.

Our old tents were a one-size-fits-all, what we're trying to do with our simpler tents now is have you guys realising this... and trying to get you watching your mushrooms and adapting the FAE to your situation. Then, once you have this all dialled-in, you should be able to repeat the same setup every time.

Worth reading on the Shroomery

• Bod's unmodified monotub tek - no holes, no polyfill, the lid flipped to leave a gap. Going since 2015, and it's where a lot of growers first saw that top FAE alone works.
• The polyfill monotub tek - holes at casing level, stuffed with polyfill. The other way of doing it.
• How it should & shouldn't look - Tmethyl's new cultivators guide, 88 pages of photos of what's right and what's wrong, fuzzy feet and thin stems included.
• Fresh Air Exchange Calculation-Measurement - RogerRabbit's rule of thumb: mist well and the water should be gone off the mushrooms in about fifteen minutes. If it is, you've got enough air.
• Proper surface moisture and when to increase FAE - the wet to dry cycle on the substrate surface, and why you don't need to fan a monotub.