Apple cider vinegar can be diluted half-and-half with water for external application, and, when stronger measures are needed, it can be used full-strength.
1 Just the stone for a flagstone patio can cost $3 -$5 a square foot or more, depending on location and the type and quality of stone, or about $600 -$1,000 for an average patio up to 10'x20,' and $1,200 -$2,000 for a larger 20'x20' area.
Determining how much a bluestone patio will cost depends on several things. 1  The average cost of a small patio is $700, but the cost can rise to $4,000 or more for a patio of around 200 square feet. 2  Those figures equal out to around $21 per square foot and include the cost of installation, materials and supplies.