support member is fixed in axial position within the lower support member 12 by means of the collar 13 and a pair of set screws 18 and 19 as seen in fig3 collar 13 is lowered from the position seen in fig1 a so that the flared diameter thereof surrounds the upper edge of the lower support member 12 set screw 19 is configured to match threads in a hole 21 fig3 to fix the collar in position relative to the lower support member 12 the position of the upper support member 11 is then adjusted axially within the inner diameter of the lower support member 12 to provide the desired height of the upper end of the upper support member 11 over the underlying soil surface at this point set screw 18 is threaded into a hole 22 threaded to accepted set screw 18 and brought to bear against the outside diameter of the upper support stake 11 as a result upper and lower support members 11 and 12 are fixed in a desired axial relationship to give the support assembly the desired extension length above the underlying soil surface as an alternative embodiment to the use of the collar 13 a threaded key 23 is configured to engage threads in a hole 24 in the upper portion of the lower support member 12 as a result when the upper support member 11 is placed in a desired position it is releasably fixed in that position by pressure against the outside diameter of upper support member 11 exerted by the threaded key 23 as described in the 39 302 patent mentioned in the background of the invention herein the lower and upper ends 11 a and 11 b of the upper support member 11 are formed in one.