How to Make a Lay Box for Breeding Crested Geckos

Late winter and early spring is when most people pair their geckos for breeding, and when my females start needing somewhere to lay. My geckos live on newspaper, so a lay box is where each female digs and buries her eggs. In a soil-based vivarium the whole tank works as a lay box. On newspaper, paper towel or any other dry substrate, you need one.

It is not only for breeding females. A lay box makes a good humid hide for any gecko, young or old, male or female, and helps with shedding.

The substrate

The main ingredient is coco fiber. I prefer compressed bricks to loose bags: better value and easy to use.

1. Put one brick in a tub. I use a 19 L (20 qt) tub.
2. Pour about 3.8 L (4 qt) of warm water over it.
3. Leave it for about an hour, until it has soaked up the water and turned light and fluffy. Break up any hard lumps.
4. Mix in about 2.8 L (3 qt) of fine play sand per brick, roughly two to three parts coco fiber to one part sand. Add half, mix it in by hand right down to the corners, then add the rest.

The sand helps the mix drain so it does not turn wet and clumpy. Use fine play sand, the kind sold for sandboxes, not construction sand, which is full of small pebbles. Geckos inevitably swallow a little while digging, and fine sand is much easier for them to pass.

The right moisture

Squeeze a handful. A drop or two of water at most should come out. It should hold together like a snowball, then fall apart as soon as you press it. Too wet and it clumps so the gecko cannot dig.

The container

I use plastic food storage containers. My favorites are Mainstays: roughly 1.1 L (4.5 cup) tubs about 15 cm (6 in) deep, deep enough for a female to dig down and feel safe. The lid's raised stacking square gives me a cutting guide.

Keep the lid on. An open tub dries out quickly. A smaller hole helps the gecko feel secure and holds the humidity in.

I have tried soldering irons, drills and hole saws. A plain razor blade is easiest. Work on a cutting board, go slowly, and pull the lid away from you rather than the blade towards you. If you are young or not comfortable with a knife, get help. Cut a hole about 5 to 6 cm (2 to 2.5 in) square.

Filling it

Drop the substrate in loosely and press it down gently with the back of your hand. Do not pack it tight. Leave about 4 cm (1.5 in) between the substrate and the lid.

A time-saver for larger collections

After filling each box, I press my knuckles into the surface to leave faint ridges. At feeding time, if the ridges are still there, nobody has dug. If the surface is smooth and patted flat, a female has been in, so I dig for eggs. With a big collection it saves a lot of time.

Of the styles I have tried, this is my favorite. I recommend giving one to each of your geckos.