One way is to reduce the ventilation, but since this causes the air to be more stagnant this is probably not a good option. I think the best option is to have a substrate which will hold a lot of moisture (like vermiculite) and/or a large shallow water dish. If you want to be sure you can place a hygrometer in the tank.
I take plastic wrap or a sandwich bag (depending on the size of the carrier) and lay it across the top of the enclosure before putting the lid on. If the animal needs 80% humidity, I cover roughly 80% of the cage top, etc. Sometimes, depending on how humid it is where you live, you'll need to increase or reduce the amount of coverage.
If you have a large enough collection, you can make an area that is of elevated humidity and just put your enclosures in there. The attached picture is of our "wet rack", which is two shelving units with painters plastic overtop. It has changed a bit since we took the pic -- we figured out where the vents should go and cut them in and we replaced the humidifyer with a better model. The thing works great, though. The shelves vary from about 65% to around 90% and none of the substrate gets wet (unless we spray as well).
EDIT: It won't let me post the pic again. Refer to the "rack systems" posting.
That is a really great idea about the towels, I am going to use it as an example on my website if you don't mind.
Humidity for me is maintained through simple misting. I tape up ventilation on high humidity species and spiderlings which are living it plastic pet-pal enclosures, and I place books ontop of tanks (or tanks on top of tanks) to restrict ventilation on aquariums with screen tops.
Another suggestion would be a warm air humidifier in conjunction with misting. This would mean leaving all the ventilation open to prevent "stagnent air" from forming, but would ensure that the enclosures would not have to be misted as often and humidity would be maintained, and would provide extra heat in the immediate area. This is a better solution for ventilation-sensitive species such as Avicularia.
I couldn't give you a specific brand. I can only tell you, buy one with a larger capacity, and one that spreads humidity to a larger area then a small-room humidifier. This might be an investment... I wouldn't say more then $100, but you never know. But from experience, the small-room humidifiers did little for me, plus I had to fill them up twice a day, which got rather annoying.
I have a K'mart humidifier , cost: around $20 - 23 , that runs 10 - 12 hours on half-tank and 24 hours full, 2 gallons.
It's in a fairly large round room, very high to the ceiling.
I live in an old Victorian house therefore the round shape of this section.
I can boost the humidity within an hour from 60 - 65% to 80% easy.
Once I forgot the humidifier overnight , about prox. 7 hours and the walls were nearly wet.
The humidity was about to hit 90%+.
No filling twice a day is nessesary because no need to run that much.
I do mist the cages, not the substrate, but cage walls and ceiling, because I have a fan running about 4 feet from the cages so it dries out faster.
The humidifier I use like a "booster" if air is to dry around and to kick up a couple of notches.
Also,,I don't remember brandname of the humidifier, but it glows in the dark .
All K'marts should have it.
I have 3 Avics., and all are doing just fine and have done succesfull molt all of them.
As for how well a humidifier works, it all depends on how dry your house is. For instance, my house uses electric heat, so it dries out quickly. I also live in western Maryland which has had a very dry winter and dry summer. So of course, that $20 2.5 gallon humidifier was not enough for me. Not all humidifiers are the same. I am glad you've found one that works for you, but that doesn't mean it's worked for everyone. And not everyone can afford to refill their humidifiers twice a day... with a fulltime school schedule, and a fulltime work schedule, I needed something that lasted a little longer... so I say a 4-5 gallon model... the price on those I am not sure of...
Plus, add to that that I had 35 spiders and several different reptiles at the time. A small humidifier like that OF COURSE would work for 3 Avic, but try that on a collection, it really isn't enough! So let me correct my advise: if you need to humidify a small collection (3-10 spiders) a small humidifier will do just fine
Try to find the name of that humidifier, it sounds pretty cool. Most humidifiers though (in my experiences with a few of them), you will find aren't that intense (or another appropriate word). In fact, I had to run my humidifier on low all the time and still only could raise the humidity for the whole collection 15% or so. If I ran it high, the tank would need to be filled several more times a day . Perhaps we had different kinds of humidifiers though. Mine was warm air, which could explain the less-efficient usage. But warm air has it's advantages since it increases temp as well, and I was using it this winter.
So next time, I might try a cold air humidifier, but I don't think it would make that big of a difference. And again, we do have different situations here though. I had like 35 spiders and several other animals, and the $20 humidifier just wasn't cutting it. It was name brand too, I just don't remember the name... I'll find it for you, so you guys can avoid it.
I have to disagree with you on this one here Kenny.
I lived in Michigan for most of my childhood. Michigan gets snow, and it certainly got snow last winter. Maryland on the other hand, is in a state of extreme drought. Michigan has some of the wettest winters because of lake effect snow (though the dry air might make you think otherwise). We are practically rationing water at this point, but luckily we just got rain which is improving the situation. But all winter, I can not say we had any more than an inch of snow. My apartments humidity level dropped down to 30% and the humidifier didn't do much for me.
Although I live in a humid part of the country (except for right now... we need rain), I find that in the winter it is extremely dry in my house. I've got a whole house humidifier, but it is not set to T levels. I would think if your house humidity is at a level where you are not experiencing a great deal of static electricity, you could probably get by with a smaller humidifier running on intervals. Just my opinion, I have no experience in this field.
Lake effects snow doesn't have anything to do with wet winter.
Air can still be bonedry even if there is a storm of lake effect snow.. also; if Dew point is down and humidity is high and air can still be dry.
I.e. 70F dew point with 75% air humidity is m o r e humid than 40F dewpoint and 80% air humidity.
So humidity is second factor a matter of fact.
As everybody knows, according to Weather Channel, winter air is also drier than desert air because there is no vapourization.
Forget warm-air humidifiers unless you have exclusively high heat, high humidity inverts. Many species don't like living in a sauna any more than you do.
Cool humidifiers are where it is at. They create a nice mist without changing the temperature too much. This means that by sorting out your temperature and humidity gradients, you can keep Ts at their prefered humidity and temp. You can also experiment with conditions just by moving them around.
Control: Two ways to do this. One is to stick it on a timer. Two is to get one with a humiditstat. The catch with the former is that you have to play around to get it just right and then change it if your conditions change. The catch on the second account is that if you are trying to humidify a room, it will probably just keep pumping out water until you run out.
I use a 2 gallon capacity cool mist humidifier in an enclosed rack. I need to refill it about twice a week. It currently keeps about 40 specimens anywhere from 65% to 90%. I am using the built in humiditstat for control and have two hygrometers that I rotate around to make sure that each area is staying at the proper humidity. As a bonus, the humidifier has a (very quiet) fan that keeps air circulating throughout the enclosure. Some carefuly placed vents ensure that fresh air is always being brought in, humidified and sent around.
The total cost of the rack is:
2 shelving units 41 CDN
painters plastic 9 CDN
TOTAL = 90CDN, or about 60 USD.
Pictures can be seen in the "racking system" thread.
"Forget warm-air humidifiers unless you have exclusively high heat, high humidity inverts. Many species don't like living in a sauna any more than you do.
Rarely will a humidifier get like a "sauna" in the room, unless you are keeping it in a closet. Some tarantulas (Goliaths in particular) actually benifit from high-heat / high-humidity enclosures. If a humidifier is making your room like a "Sauna", I would worry about your computers and electrical devices sparking or overheating.
"Cool humidifiers are where it is at. They create a nice mist without changing the temperature too much."
The point of warm air humidifiers are to increase the immediate temp. without using a heating device. This is a good idea during the summer if you live in a cooled house, but need a little extra heat then usual. Though, I have a theory that cool humidifiers are more effective then warm at delivering moisture in the air.
"This means that by sorting out your temperature and humidity gradients, you can keep Ts at their prefered humidity and temp."
Few tarantulas differ in temp. requirements. The ones I can think of at the moment are Aphonopelma species (which can thrive on cooler temps), and Goliaths (which need higher heat then usual). 80-85 (somewhere in between) is the best temp. for all your inverts, weather they are wolf spiders, tarantulas, or an Emperor scorpion (while some other Scorpions do have higher temp requirements). As for humidity "gradients", this is effected by the distance you place the spiders from the humidifier, and how much the enclosure was initially misted. You really can't maintain a T. blondi souly on a humidifier unless it is really close to it. The purpouse of such a device is to prevent excess moisture loss, not to totally suppliment the enclosure with humidity (in most cases if you have a broad range of spiders at differing humidity levels).