There has been a recent debate about this subject on the Arachnid-World mailing list recently, so to help clarify the options for arachnid keepers, I decided to re-publish an article I wrote a while ago. Hopefully it will help?The Never-Ending Substrate Debate
Whatever type of arachnids you keep, there is undoubtedly a requirement for a substrate that allows the tank's occupant to burrow (if it wants to) and to help keep the humidity in it's tank at an acceptable level, without encouraging mould or fungus that may harm or even prove fatal to the occupant.
The common options that are used by most arachnid keepers are as follows (this includes both the positive and negative aspects of each option).Peat:
Many of the professional keepers swear by this as a substrate, however although peat hold moisture quite well, the following are common problems: Mould, mites, fungus and other unwanted growths.
To counter this the substrate should be microwaved (only when it's dry, otherwise their is a possible fire risk!) This will kill any mould or fungus spores, and anything else, such as mites.Vermiculite:
Other keepers feel that vermiculite is the *perfect* substrate (including me) as it doesn't tend to encourage mould, fungus or mites. Some of you may wonder what vermiculite is, well below is the answer."Vermiculite is the geological name given to a group of hydrated laminar minerals which are aluminium-iron magnesium silicates which have the appearance of mica, and is found in various parts of the world. When heated quickly to an elevated temperature, particles of vermiculite exfoliate by expanding at right angles to the cleavage, into worm-like pieces (the name vermiculite is derived from the Latin 'vermiculare', to breed worms). This characteristic of exfoliation, the basis for commercial use of the mineral, is the result of the mechanical separation of the layers by the rapid conversion of contained water to steam. The increase in bulk volume of commercial grades is 8 to 12 times, but individual flakes may exfoliate as many as 30 times. There is a colour change during expansion that is dependent upon the composition of the vermiculite and furnace temperature.
Horticultural vermiculite is permanent, clean, odourless, non-toxic and sterile. It will not deteriorate, turn mouldy or rot. The pH is essentially neutral (7.0) but owing to the presence of associated carbonate compounds, the reaction is normally alkaline. The pH, colour and chemical composition of vermiculite will vary depending on the source from deposits around the world. Horticultural vermiculite has the excellent property of improving soil aeration while retaining moisture. "
Some tarantulas, especially arboreal species don't like it as it tends to stick to their feet.Potting Soil:
Some of the experts use this instead of peat, it still needs to be sterilised BEFORE use, otherwise you may get some unwanted guests or growths.Coconut Fibre:
This is a relatively new option, some of the regulars on the arachnids mailing list have tried and reported thus:"I think Harry is right about the make-up of the Bed a Beast (Coconut fibre etc.). To me it looks like peat, works like peat, and I have had no problems with eggs or other pests. I do Microwave all store bought substrate, I don't trust them.
Moisture retention is almost to good. You have to be careful not to get it to wet or your tank will rain for a month. My burrowers have no problems and quickly build tunnels. Two of my tanks have not been touched for 8 months (except for feeding and maintenance) and are doing well.
The only problem I have had is if a cricket hangs around to long, 2 - 3 weeks later I have pinheads. "
Another user reported ...."I use a product called "Bed-A-Beast". It comes in a 4" X 8 "X 2" block and when placed in water it yields about 8 litres of bedding. One block fills my five - 10x24" tanks, a dozen small containers for spiderlings and leaves enough to spill on the kitchen floor. The company (Pet- Tech in Van Nuys, CA) claims it is an annually renewable resource from Sri Lanka, can be recycled to the garden and is a similar replacement for Sphagnum Peat Moss. For me and the T's its cheep ($4.99 a block) and works great and is easy to store till made. Hope this helps. i suppose that i forgot to mention the utility of micro-waving the material first. as long as it is dry, it will not get too hot in the microwave, which only works by heating water. "
Some keepers use a mixture of peat or potting soil with vermiculite, one keeper gave this reply:"For burrowers I use a peat/vermiculite mix - prob. 50:50, but I don't really measure it.
The vermiculite helps stop the peat drying out too fast and also stops it "clumping" together too much (that's why gardeners use it, after all) - thus it might help prevent cave-ins?
I've never really had a burrow collapse - the tarantulas always seem to web all over the inside enough to hold it together.
I have had mite and mould problems in peat/vermiculite mixes, but never in vermiculite.
what i do is make mixes of peat, vermiculite, sphagnum and top soil, and then adjust it per the requirements of the specific tarantula.
spiders that need higher humidity get more vermiculite. hardy burrowers get extra sphagnum, which i have seen many reinforce their burrows with. it seems to work to pretty well. "
So you see there are a number of possible substrates for your charges. I think it's time for a little experimentation, go to it!
PS Avoid wood chips, especially pine chips, as these can prove fatal to arachnids.
Labels: arachnids, husbandry