Carl

The jumping ones are springtails and the crawling ones are almost certainly mites. Both are normal bin fauna and neither hurts worms. They're decomposers doing the same job as your worms on smaller material.

That said, an explosion in numbers is a signal. Springtails and mites both boom when the bin is too wet and too acidic, and "a lot of fruit scraps" is exactly how that happens. Fruit is wet, sugary and acidic.

What I'd do:

• add a good handful of dry shredded cardboard or coir and mix it into the top few centimetres
• lay off fruit for two weeks, feed veg trimmings and coffee grounds instead
• a sprinkle of crushed eggshell or garden lime raises the pH a bit, which the worms prefer anyway

Populations settle back within a couple of weeks once it dries out.

Nothing went wrong. That's what a hot pile does — it burns through the easily available nitrogen and sugars in a few days, the thermophilic organisms run out of food, and it cools. It is absolutely not finished, it's just moved into the slow phase where fungi and invertebrates do the rest over a few months.

A turn will usually give you a small bump, maybe to 100-110F for a day, if there's still fuel. If turning does nothing at all, the easy nitrogen is gone.

If you want it hot again you have to feed it: fresh grass clippings, more manure, or coffee grounds, mixed in properly rather than layered on top. Whether that's worth doing depends on whether you want speed or don't mind waiting.

One more thing, since horse manure is in the mix: if it came from a stable that isn't yours, be a bit careful about persistent herbicides in the hay. They survive composting and stunt tomatoes and beans badly. Grow a couple of bean seedlings in a pot of the finished compost before you spread it on a vegetable bed.

You built a nitrogen soup. Kitchen scraps, coffee and grass are all greens, all wet, all high nitrogen, and there's nothing structural in there to hold air. Ammonia smell is literally nitrogen leaving as gas because there isn't enough carbon to bind it.

Fix, today:

• add dry browns until the texture changes. Shredded cardboard is the best thing you have in the house, torn into pieces not shredded to dust. Dry leaves, straw, or ripped up egg cartons all work
• you will need more than you think. Roughly equal volume to what's already in there, sometimes double
• turn it, wait a day, add more if it's still glossy and heavy

Target feel is a wrung-out sponge — squeeze a handful and you get a drop or two, not a trickle. Tumblers are especially prone to this because they don't drain and there are no worms or soil organisms to buffer your mistakes.

For four litres a week in a small paved garden with close neighbours, honestly neither is ideal, and a worm bin might be the better answer. Kitchen scraps alone are exactly what worms want, it takes up less space than a tumbler, it produces no smell if you run it right, and it's fully sealed against rats.

If you want to pick between the two you named:

• tumbler: sealed, rat-proof, no smell if the mix is right, but slow at low volumes because you never build enough mass to heat, and it needs browns you'll have to source
• pallet bin: composts better and takes garden waste happily, but it's open, it will get rodent visitors if you put cooked food or a lot of fruit in, and on a paved garden you'd want it on soil for the drainage and the worms

At your volume the tumbler will take five or six months per batch. That's fine if you're patient.

Dark and crumbly with eggshells and twigs still visible is finished for practical purposes. Eggshells take years and mean nothing. Twigs you screen out with a bit of chicken wire over a wheelbarrow and throw back in the next pile as structure.

Realistic timeline where the pile freezes: about 12-18 months from build to use if you're not managing it hard, versus 4-6 months in a mild climate. The frozen months are simply a pause, not a loss — the pile picks up in spring roughly where it left off. Freeze-thaw cycles actually help by rupturing plant cells, so material often breaks down faster in the first weeks of spring than it did in autumn.

Smell test beats looks: finished compost smells like woodland floor. If it still smells sour or sweet, give it another month.