Hello Linda and welcome to the hobby and forum! :clap: I myself just recently started the hobby with a
saved mantis too, Susanna. Seems to be a popular way to get started, especially this time of year.
Post some pictures of your mantis/habitat and someone can identify your mantis, and give more help as they can see what is going on in your mantis habitat/tank.
There are much more knowledgeable people here than me, but here are a few things I'll point out to help and provide links to other topics for information.
The dirt should be kept shallow (or removed?), as the only thing it will do is provide a place for the crickets to dig and hide. Many people here either use paper towels, sphagnum moss, or coconut husks for the
substrate (ground). I personally use
Plantation Soil, as it is ground coconut husks so it is anti-fungal and helps regulate humidity.
The
water sponge/dish as long as it doesn't have standing water, is a good source of water for the crickets. Your mantis however, will most likely never use it and gets it's water from prey (crickets) she eats and misted water. You mention sprinkling water, not sure what that is, but for your mantis you should use a new spray-bottle set to mist. Then
mist the habitat (branches/leaves) and only do enough so any water drops evaporate in 30 minutes. Too much water can cause mold or fungus in your habitat.
Not sure how many crickets you have in the habitat with her, but crickets not intended for
a current meal should be kept
their own tank (
another link). Large amounts of crickets with your mantis will only stress her out from their constant presence and movement, and possibly other problems. The only feeders you can house with your mantis safely they say are roaches (don't keep roaches myself).
The crickets themselves will
need to be feed (
or here)/water misted, as they will usually start to die slowly in a few days if they are not taken care of. They are a
good source of food for your mantis, if they are properly feed - my mantis eats crickets with no complaints.
At that point adding a dish of "dirt" to your cricket habitat will allow them to breed, and save you money/trips. My crickets have been busy lately laying eggs in the "dirt" (I use a 1 1/2" tall cut empty oatmeal container filled with Plantation Soil). In a few weeks I'll know how that works out as they will start hatching,