Iowa Code § 639.50: Determination and sale.

If they are of the opinion that the property requires soon to be disposed of, they shall specify in writing a day beyond which they do not deem it prudent that it should be kept in the hands of the sheriff. If such day occurs before the trial day, the sheriff shall thereupon give the same notice as for sale of goods on execution, and for the same length of time, unless the condition of the property renders a more immediate sale necessary. The sale shall be made accordingly. If the defendant gives written consent, such sale may be made without such finding.