If you have sandy soils, lime will leach down thru the profile. I would do a soil test and amend the soil. Disk in the ammendments, unless on sandy soils, then plant buckwheat and try and triple crop it. This should get you into september. You will have plenty of weeds and grasses in your buckwheat by the 3rd time you cut it, which will provide you with carbon credits and thatch. Spraying gly, is a personal choice, although if the standing vegetation is real thick, i would spray 2 weeks before seeding. Add some radish or ptt to your mix to help with hardpan soils, plus it will feed the soils.