Setting up new spiderlings
We start here because these core principles of spiderling care are more important than anything to be discussed in future essays of this knowledge base.
If you understand tarantula spiderling care you can care for any age thereafter.
Temperature
Temperature and moisture are the most important factors in spiderling survival.
Temperature is easy. With very few exceptions, anything in the range of 70-80°F (21-27°C) permits activity and growth. Brief dips to 60°F at night or peaks to 90°F in the day are probably okay, but the narrower 70-80°F range is achievable in most US homes.
Moisture
Moisture is fundamentally easy, but involves a little explanation.
Spiderlings lose water faster than adults. Risk of spiderling dehydration holds equally for desert species like the Arizona blonde as well as for drought-intolerant rainforest species like the goliath birdeater. While the adults of these should be kept in widely different states of enclosure moisture, not so their spiderlings. Spiderlings as a rule can’t tolerate drought. So whether Aphonopelma chalcodes or Theraphosa blondi, their spiderlings do better when kept closer to water.
But that doesn’t mean wet
Wet substrate fosters microbial growth (fungi, bacteria) and leads to a host of visitors, namely fungus gnats, grain mites, Phorid flies and nematodes. Some of these depend on wet food remains also being present. Others are aquatic (nematodes) or have aquatic larvae (Phorid flies). Tarantulas, whether spiderling or adult, never seem to thrive very long on wet substrate.
We go so far as to generalize, “A wet tarantula is a dead tarantula.”
Use slightly dampened substrate and elevated humidity
The technique is painfully simple. Begin by making slightly dampened substrate: Mix 1 part water with 10 parts dry substrate. (Dry substrate forms a dust cloud when disturbed.) Stir well. You won’t be able to wring water from the mixture, but it has enough moisture. Fill your enclosure about halfway with this slightly dampened substrate. Restrict ventilation to allow humidity to rise.
That’s it. We use this basic technique, for every tarantula spiderling we keep. The trickier part is ventilation.
More on ventilation
Obviously, spiderlings need ventilation. Fortunately, for low-metabolism animals like tarantulas, one can limit ventilation such that humidity accumulates yet sufficient gas exchange still occurs.
Many commercially available enclosures have a lot of holes. Sometimes one can’t achieve 90% humidity in them due to over ventilation. Such setups tend to suit juveniles through adults better than spiderlings.
DIY
In a 1-pint enclosure (~500 mL), one needs no more than 4, 1/8″ holes in the lid. More may be ok, but depending on your room’s temperature and humidity, substrate may dry faster than expected. So monitor closely.
One of the first things you’ll notice with insufficient humidity is that the spiderling will go off feed. Cover some holes with tape, re-establish slightly dry substate and spritz with an atomizer. If you’ve intervened early enough, and premolt isn’t the case, your pet will resume eating.
There are other issues certainly, as well as other solutions to the one presented above. We’ll try cover some of these topics as they arise.