Yes, you can compost dandelions – but a bit of care is needed.
Dandelions with their roots attached should be avoided as they have a tendency to regrow. Ditto heads of dandelions that have gone to seed: being put into a resource-rich growing medium then spread it around your garden is basically the seeds’ biggest wish come true.
Don’t forget though that for weeds, dandelions are actually pretty useful: the root can be dried and used as a coffee substitute, the flowers can be used to make tea or wine, and the leaves can be eaten in a salad or as a cooked green. And if you don’t fancy eating them, chickens, rabbits and the like enjoy them as a green snack too. It’s better to use them if you can, rather than just composting them.
Beware of composting dandelion flowers. They are self fertile and so can still set seed when they are in the compost. Even unopened flowers can set seeds.
If placed in cool compost you can still end up spreading seeds over your garden.
This May we could not now the dandelion flowers as the ground was too wet and soggy for our mower. There are dandelion tufts everywhere and they will be in the grass cuttings as we mow in the first dry period for weeks. What should I do with the cuttings? They should not go into the compost heap I think? Can you advise?! Thank you. Claire