This can depend on your ground-freeze level, but our standard kit is designed for the poles to be inserted 24" into the ground (please also see NOTE below). This leaves 11'4" of frame above ground (allowing 8" of net sag on the ground when used with a 12'H net), and also allows for 12" of extra room on the width (when using a 14'W net), which compensates for ball ricochet. Each rib also includes 2 PVC piping sleeves for inserting into ground.
You may also add or remove steel snap hook links as needed to adjust your height.
Please note that it's recommended to allow "net sag" on the ground to contain balls and create slack, which reduces tension and extends the net life-span.
NOTE FOR CABLE KIT USERS:
When using a cable kit with your frame, you will insert your center upright poles 18" down, which will leave your center cross-members 6" higher than your cable lines. This will allow the lines to pass under the poles, and enable you to affix the cables to the collars on the center cross-members for support points -- this will also expand your height in the center, creating a "tent effect". You may also link multiple snap-hooks together to keep the cable lines 6" below the center cross-members, if ricochet is an issue.
More nCage In-Ground Batting Cage Frequently Asked Questions