Care instructions for your gecko might say "include a shed box or include a nest box" but what does that mean?
All geckos appreciate a humid soil-filled box to hide in and help their shedding process. Female geckos require a box like this to lay eggs in. Even females who have never been exposed to a male will lay infertile eggs during breeding season once they are large enough. These eggs will not hatch and can be thrown away (there is some evidence that Crested Geckos can lay parthenogenic eggs but it is very rare).
If you have a natural tank with a soil substrate then she will simply dig in the soil and lay them there. Technically the box isn't needed in these conditions, but I still keep boxes in my natural tanks because the humidity is higher and I know the soil is moist, while the soil in the tank might dry between watering. Also, this allows me to track whether or not she is laying eggs or having trouble laying monthly. I can also check the quality of the eggs. Under calcified eggs are a sign that she needs an increase of calcium and vitamins in her diet for instance.
What if you have a male?
A male gecko will use the box to hide and shed in. It will help him to have a better shed if his body is uniformly moist. Keeping the entire cage this humid is not healthy though, so a box allows you to offer a high humidity area in a safe way.
Making a box:
The easiest way to do this is to buy a Glad disposable plastic container. Chick-fil-A salad or cool wrap containers also work.
All geckos appreciate a humid soil-filled box to hide in and help their shedding process. Female geckos require a box like this to lay eggs in. Even females who have never been exposed to a male will lay infertile eggs during breeding season once they are large enough. These eggs will not hatch and can be thrown away (there is some evidence that Crested Geckos can lay parthenogenic eggs but it is very rare).
If you have a natural tank with a soil substrate then she will simply dig in the soil and lay them there. Technically the box isn't needed in these conditions, but I still keep boxes in my natural tanks because the humidity is higher and I know the soil is moist, while the soil in the tank might dry between watering. Also, this allows me to track whether or not she is laying eggs or having trouble laying monthly. I can also check the quality of the eggs. Under calcified eggs are a sign that she needs an increase of calcium and vitamins in her diet for instance.
What if you have a male?
A male gecko will use the box to hide and shed in. It will help him to have a better shed if his body is uniformly moist. Keeping the entire cage this humid is not healthy though, so a box allows you to offer a high humidity area in a safe way.
Making a box:
The easiest way to do this is to buy a Glad disposable plastic container. Chick-fil-A salad or cool wrap containers also work.
This is the salad size. You can use sandwich or larger sizes as well. The goal is to have it small enough to trap humidity, large enough for the gecko to climb in, move around, and dig tunnels.
I either use a hot glue gun or a sharp box knife to melt or cut out that circular section in the top. This gives the gecko an entry point. You can also use the hot glue gun to melt breathing holes around the top. Don't get too crazy with ventilation or you won't hold the humidity in. Also, don't do holes near the bottom or your water will pour out when you add it to the box.
Add your substrate. I prefer moss, but some people use ABG mix or other soil substrates. I don't like coir by itself, I've had a couple of mine eat it while digging and get impacted. It is okay mixed with moss though.
I either use a hot glue gun or a sharp box knife to melt or cut out that circular section in the top. This gives the gecko an entry point. You can also use the hot glue gun to melt breathing holes around the top. Don't get too crazy with ventilation or you won't hold the humidity in. Also, don't do holes near the bottom or your water will pour out when you add it to the box.
Add your substrate. I prefer moss, but some people use ABG mix or other soil substrates. I don't like coir by itself, I've had a couple of mine eat it while digging and get impacted. It is okay mixed with moss though.
I like Exo Terra Forest Moss. You can usually find it in a pet store that has a reptile section, if not you can definitely find it online on Amazon or other online pet stores. This is a compressed brick and it swells up when you add water. A little bit goes a long way. Use about 1/8th of the brick to start. Add warm water to cover and see if that is enough to fill your box. You can put the dry moss and water directly in the box. After the moss has rehydrated (15-20 minutes), stir the moss to make sure it is all rehydrated, then pour off excess water. If it is too wet it will cause mold. This product is also a good substrate for your cage by itself, mixed with coir, or over the top of the coir.
Check the box every week to see if it is damp, add water if needed (not too swampy), check for mold or droppings (remove the affected moss if found), and check for eggs if applicable. Add more moss as needed if you or the gecko are removing it. Change out the moss entirely every season or if the moss starts to smell or degrade.
Check the box every week to see if it is damp, add water if needed (not too swampy), check for mold or droppings (remove the affected moss if found), and check for eggs if applicable. Add more moss as needed if you or the gecko are removing it. Change out the moss entirely every season or if the moss starts to smell or degrade.