How do you insulate a crawl space?

In 1894 someone dug a hole in the ground, lined with field stone, picked up a farm house some distance away and plunked it down on the foundation.  Then they added a porch and two bedrooms on the site and then thought a kitchen would be nice.

Everything is on the 3ft. thick foundation except the kitchen and back porch.  That sits on a block foundation with a 3 ft. high hole underneath to access plumbing etc.  To access this area you have to climb up a step to a 2 X 2 foot hole that's 4ft. off the deck.  The floor is dirt.

I've laid poly on the floor and insulation on the (foundation) walls.  The area is 15X15 and the last 4ft. go under the rear porch.  I've replaced the awful wood porch with Trex and built a wall of 3" blue foamy stuff between the kitchen and porch area.  That helped.

Question:  Do Insulate the dirt floor or insulate the ceiling of the space? Ceiling is the actual kitchen flooring.

I run a stove n the basement which, once the big stone is heated up works well, but no air seems to be headed to the 2X2 hole.  The goal is to make the kitchen floor warmer.

Whaddaya got?

Every crawl space I've ever seen, including mine, has insulation between the floor joists.

But that apparently, is not the way you are supposed to do it!

https://www.thespruce.com/how-to-insulate-crawl-space-4796956

Eagerly awaiting some input from someone knowledgeable about the current thinking in crawlspace insulation.

I've done something very similar. Insulate the ceiling of the space, so the crawl space remains cold. You'll need to put vapour barrier between the ceiling and the insulation. I used heavy poly sheeting, in a continuous sheet, then stuck the batts between the joists. They didn't want to stay up in the joist spaces, so I nailed chicken wire to the joist bottoms. You could also use 1 x 2 strips, but I had chicken wire lying around. It made a big difference to the room above (bedroom), which had always been cold previously.

Current building science says that you want to fully seal the crawlspace from everything but the floor above. This makes it basically conditioned space like the living space within your home. Insulate and air seal the walls (no venting). Attach and seal the vapor barrier on the floor of the crawl to the walls/insulation. There's not usually insulation on the floor of the crawl, or the floor of the home. For the fieldstone sections, the easiest option is probably spray foam or building a wall next to the stone to insulate. Don't forget to insulate any joist bays with rigid foam (fully sealed edges) or spray foam.

You will need to monitor/mitigate humidity once the crawl is sealed up. This can be done by adding or modifying ductwork to blow conditioned air into the crawl and/or using a dehumidifier. If you're adding HVAC in the crawl space it can add a lot of volume to the building envelope, so HVAC systems need to be sized for the added space.

If Radon or other soil gases are common in your area, then having a way to control and vent that to the exterior of the home is critical before you encapsulate and seal everything up.

You can search for 'crawlspace encapsulation' to get some ideas. It's a growing business in many parts of the US, and the companies that do it charge a lot. But there's nothing inherently difficult about it, it's just plastic sheeting, tape and some insulation in select areas.

If we stay in our current house much longer, I'm going to do ours. I've been getting quotes in the $14-18k range (we have a large crawlspace), but I could DIY it with similar materials purchased online for around $5k. This site has some of the best prices that I've found for professional level products for a DIYer.

^ That's what I ended up doing to my crawlspace. Was insulated with batting in the joists but had a mold issue so that came out and anti-fungal agent sprayed. Mold returned. Crawlspace is now encapsulated and sealed with a dehumidifier. Haven't had issues since. Been over 2 years. Bright side is my crawlspace being 6 ft on one end with the entrance door and a little over 3 ft on the other end it makes nice storage and being sealed with a dehumidifier it is basically climate controlled, temp stays in the low 60's with about 40% humidity year around. At least according to the meter I have. Water heater being down there probably is the reason for the constant temp.