Anytime. You may have to put a baggie or something over it until it puts out some pups. I've got two leaves with pups in perlite and still have them under a plastic lid.

Here they are.

Thanks hcmcdole. How long will they need the extra humidity?

You can wean them by cracking the lid (cover, baggie) more and more each day. If they can stand on their own then they will be ready for "normal" household air when the cover is completely off for a day or more. If they wilt and the soil is moist then they are not ready. You can simply cover them when this happens and let them recover and try again.

I made a huge mistake one year where I had huge plants growing in a 29 gallon aquarium. I thought they were so big that they would be fine so I removed them all. They went into severe wilt within a day and most died due to the sudden change in atmosphere. If I had known better at the time I could've moved them back to the aquarium and weaned them slowly.