Do I minus the original cost from it or add it? The Landscaping supplies are 742.00. But I have a on hand remaining of 200.00

You will need to do an adjusting entry after your trial balance to get your Slandscaping Supplies Account balance to equal your actual account balance.

The adjusting entry will be:
Debit Landscaping Supplies Expense for the difference between your landscaping account balance and your actual onhand balance
Credit Landscaping Supplies for the same amount as your debit.

This entry will transfer your used supplies out of your asset account to your expense account because you have used the items.