Nighttime Diapering

Fear not, nighttime cloth diapering is not all that different from using cloth during the day! The name of the game when it comes to nighttime diapering is still simple - get enough absorbency in the diaper to match your baby's output, and put that absorbency where your baby needs it most!

Heads up - I included a multitude of scenarios and possibilities in the following tutorial. It is fairly comprehensive (aka might seem like far too much to keep track of at first). But I promise it is not hard find what will work for you. Simply choose your baby's age - 'Newborn' or 'Infant/Toddler.' If you are shopping for an Infant/Toddler, then find your baby's favorite sleeping position - 'Side-/Stomach-Sleeper,' 'Back Sleeper' or a bit of both. See, easy peasy!
Choosing a Diaper
First, for those with newborns your nighttime cloth diapering needs are different from folks with infants or toddlers. Anytime a baby is still pooping around the clock, you will be changing diapers around the clock. I cannot recommend enough, if your budget allows, that you buy a few 'super-easy' diapers for those wee hours of the morning (when you are so tired you cannot see straight).

Note: I use quotes around 'super-easy' as what that looks like will be different from family to family. If you are using Flats or Prefolds during the day, maybe upgrade to a few fitteds for overnight changes. If you are using snapping fitteds during the day, try some All-in-Ones for overnight, or maybe some velcro-closure fitteds.
For more information on newborn diaper options, check out The Newborn Diaper Shop.

Absorbency Needs
Once your newborn is sleeping longer stretches at night, you may find that their output out-paces your diaper's absorbency. If the diapers still fit your baby well, you can still make them work for you! I recommend adding a short and slim doubler to the diaper (I recommend a Bottombumpers Organic Cotton Doubler or an AppleCheeks Bamboo Booster).
If your baby is quite small, even a baby washcloth or repurposed t-shirt, flannel receiving blanket or bath towel cut to size will work. Just make sure that whatever item you use is cotton (or at least a high % is cotton), and that it has been thoroughly washed - just like your cloth diapers, you don't want any fabric softeners or detergent residue in the fabric.

To use the doubler:
All-in-Ones: lay the doubler inside the diaper, and secure diaper closed around baby
Fitteds, Prefolds or Flats: I recommend laying the doubler inside the cover, outside of the diaper. Since newborn's poop is so runny you still want the poop-stopping-power that the leg gussets of the folded prefold or flat or fitted provide.

Infants & Toddlers 
Choosing a Diaper
Once your baby is no longer pooping during the night, you likely will no longer change your baby's diaper at night (it is a personal choice - I know some families who change their toddler every time little one nurses, even if baby only has wet diapers through the night). Enter high-absorbency diapers!
There are a couple of ways you can decide the nighttime diaper that will work best for your baby:
First, is baby primarily a side-, stomach- or back-sleeper?
Second, is baby sensitive to, or bothered by, moisture or synthetic fabrics? 
For side- or stomach-sleeping babies
I recommend a Fitted diaper. Fitteds provide 360-degree coverage - no matter what part of his body baby is laying on, there is always absorbency beneath him.
Fitteds are made of natural fibers, whether hemp, cotton or bamboo. If baby doesn't like to feel wet, you'll want to add a fleece liner to wick the moisture away.
There are two covers to pick from - a PUL cover or a wool cover. Both are effective, so I recommend choosing the one that matches your lifestyle better. Wool requires less frequent washing (most wool users wash every 1-2 weeks), but it does require lanolizing to stay waterproof. PUL needs to be washed every couple of days, but it can be machine-washed.
Having Leaks?
If your baby wakes up in the morning with a fully-saturated diaper, you'll want to start adding a doubler to your nighttime solution. You'll figure out quickly how you like to use that doubler - if your baby is wearing a sized fitted, you'll likely want to lay the doubler inside the cover so the fitted still fits well through the legs and waist, OR, if you are using a wool cover, you'll find the doubler sits better if placed inside the fitted. 
Using a well-prepped fitted+doubler and a well-fitting cover, and still having leaks? It might be that your baby urinates so fast that the moisture travels so fast the diaper cannot absorb fast enough. Solution! Layer a second cover over the diaper. I know what you are thinking, Seriously? You have got to be kidding. But it is true. Adding a wool cover over your fitted+PUL cover is a fantastic solution. If you've read about the powers of wool, you'll know it both holds in moisture, in addition to allowing moisture to evaporate. This ensures anything that might escape the PUL cover is well-contained. In addition, as the wool is a back-up cover, you will likely rarely need to wash and lanolize.

For back-sleepers
I recommend a Pocket Diaper. A Pocket Diaper's absorbency runs front to back, with the majority of it at the back. Thus this is fantastic for a baby on her back, as that is where gravity will take the urine. 
Pockets are typically mostly synthetic fabrics. If your baby is sensitive to synthetics (ie. polyester fleece or suedecloth), then I recommend a natural fiber pocket like Blueberry Bamboo Deluxe Pockets. These both put bamboo fleece against baby's bottom.
Having Leaks?
First, if you are using a Pocket diaper and experience leaks, even though the diaper doesn't seem to be close to saturated, I recommend taking a look at this troubleshooting guide. Now, if your baby wakes up in the morning with a fully-saturated diaper, you'll want to start adding a doubler to your nighttime solution. As most Pocket diapers include a microfiber insert, I recommend a natural fiber doubler. Microfiber absorbs quickly, but a natural fiber like bamboo or hemp will absorb more. To marry them - layer the microfiber insert inside the pocket first, closer to the inside wicking fabric, then add the doubler towards the outside.
For Babies Who Sleep Like Egg Beaters
If your baby is one who likes to defy labels like 'side-,' 'stomach-' or 'back-sleeper,' then this solution is for you! Enter second waterproof layer! This layer will halt any possible leaks no matter what position your baby sleeps in. 
Wool is a great option. Or, even a pair of fleece pjs (wash the fleece jammies with a healthy dose of fabric softener, as fabric softener will up the waterproofing abilities). Both of thees covers will repel liquid back into the diaper, keeping it where it belongs.
My favorite nighttime diaper (and this is what we use for our daughter who is a 75% side sleeper - 25% back sleeper) is a Pocket diaper + a doubler + a wool soaker. This ensures all the moisture is contained, while still accounting for the fact she likes to burrow into my side while laying on her side and doesn't like to feel wet at night.
Final note - Fleece! This is an inexpensive alternative to Wool, and is machine washable. I don't find it quite as waterproof as wool, but if you are looking for that second cover option on a budget, I recommend Fleece Soakers. I'm happy to recommend some WAHM-made brands I've loved, if you are interested in learning more