I am getting really confused about the difference between retainers and deposits.

If i have someone wanting to use a space in July i want to charge to keep that place open for them. My thought is to charge a set fee per week to prevent me from offering that place to someone else.

Then in July she will start paying the full amount. I do not want to then take off the money she has paid as a retainer off of the first months fee because as i see it i could have sold that place to someone else and been paid a full fee. Is this right?

So how is a deposit different?

What you have explained is how a retainer works. Remember you can only charge a retainer if a space is available and being held for a new mindee at a future date. I think it is usually half fees. A deposit is 2, 3 or even 4 weeks fees. Paid on completion of contracts. It is to make sure a parent is serious about starting, also if they then leave without giving notice you have money held from them. Deposits can be refundable or non refundable!