Transform sand into the soil on my city flat's balcony

Hi! I'm very new to gardening (no experience at all).
I've got a pan with sand on my balcony.
And I wan't to find out if it is possible to transform sand into the soil by growing earthworms, adding mulch etc.
Can you give me advices how to do it?
1) Is it possible at all?
2) I am going to put some soil with worms into my sand. Feed them with organic waste. I will put waste under the mulch. Is it correct?
3) How can I make earthworms feel good into the sand pan? Should sand be humid all the time? How much water should I give there? Maybe I should make kind of drainage so that surplus of water can be set aside?
4) Any other advices?

Thank you!

You need to have a larger, shallower pan under your sand&worm pan to (1) allow for drainage and (2) catch what drains so you can use it to fertilize your other plants. If you add organic waste and water it frequently, you will replicate natural conditions and your worms can thrive and make soil in the process. What drains off should help you raise a nice crop of tomatoes or other vegetables on your balcony.

John Elliott wrote:You need to have a larger, shallower pan under your sand&worm pan to (1) allow for drainage and (2) catch what drains so you can use it to fertilize your other plants. If you add organic waste and water it frequently, you will replicate natural conditions and your worms can thrive and make soil in the process. What drains off should help you raise a nice crop of tomatoes or other vegetables on your balcony.

Thanks a lot! Growing tomatoes is a great idea too! However the main goal is to transform sand into the soil. Just for fun and to see how things work I am going to 1 month vacation soon. Do you think it's possible to make system live without my care? Rain water can be collected into the pan but what about organic waste?

Nikita Sidorenko wrote:
Thanks a lot! Growing tomatoes is a great idea too! However the main goal is to transform sand into the soil. Just for fun and to see how things work I am going to 1 month vacation soon. Do you think it's possible to make system live without my care? Rain water can be collected into the pan but what about organic waste?

You have neighbors? Can they toss their organic waste from their balcony to yours? If not, just put a lot of leaves on top of the pile and leave it out in the rain.

John Elliott wrote:You have neighbors? Can they toss their organic waste from their balcony to yours? If not, just put a lot of leaves on top of the pile and leave it out in the rain.

Don't think neighbors can help. Will use lot of leaves, thank you!