Not sure what kind of Turnips you have or what part of the country you are in; howeever, here are some comments ...
- As above, you should've planted by Aug 1st if possible in the northern 1/3 of the US. Mine were planted July 21st and the leaves are 18" plus inches with the stems just starting to bulge.
- Disk your ground good and then run your drag over it.
- You can then use a hand spreader to broadcast the turnips. Then just run a roller over them to press them into the soil. No need to run the drag as you may cover them up too much. Normally you plant the seed to 4 times it's diameter in a firm soil bed.
- Plant turnips 3-4 lbs per acre. I add 2 lbs of Rape and 2 lbs of Red Clover.
Then pray for rain and some warm sunny days for the next 60-75 days.