The Maplewood Richmond Heights School District has worked since 2012 on plans to address the surprising student population growth, especially at the Early Childhood Center (ECC). The school board Thursday approved a measure to address the needs at the lower levels. The board voted unanimously to put a bond issue on the April ballot for a new preschool. The MRH School District will ask voters in April to approve Proposition K, a $6.1 million bond to buy property and build a new preschool. The cost to home owners would be approximately 15 cents per $100 of valuation.