There is moisture coming from under the house, under the kitchen sink, it is causing mold . The landloard knows.how can I keep it dryer under the sink so I do not get more mold. I tried a fan, it did not work.

What is under the litchen floor, a crawl space? If the underside of the flooring and the joist are damp I am not so certain its from the ground. A very small leak or weep can soak the wood and cause mold. Tell me more about what's under the kitchen

There is a crawl space under the whole house. The landlord said its all from the ground water under the house. The only place we are having the trouble is under the kitchen sink, we have had the plumers out 5-6 times and they said they can't do anything.

Since this is a rental I can't give you much in the way of "fixes" Any repair should be done by the owner. If this mildew bothers you then you can give the owner notice now that you do not intend to renew your lease when its up. This may or may not get him to consider further repairs

Do u know of anything that will keep the moisture down, or anything that will soke up the moisture?

A dessicant would help but ones like this Pelican Products 1500D Peli Desiccant (Silica Gel) (http://www.google.com/products/catalog?hl=en&bav=on.2,or.r_gc.r_pw.&wrapid=tlif130119556247710&q=desiccant&um=1&ie=UTF-8&cid=18249650935041545036&sa=X&ei=M6uOTdr5E6OU0QHk1KXBCw&ved=0CE8Q8gIwAw#) only do 3 c/f. Maybe a big bag calcium chloride left open wiil help. Is the crawl space ventilated? Proper venting would be the greatest help

The crawl space is ventilated. I need to know how to dry out the cubbord under the sink.

Which is wetter, the joists under the floor or the cubboard?