The hoe doesn't seem to work and giving birth does not reduce/reset the purple meter.
Viewing post in My Life On Seedbed Farms comments
Thank you for report. Both of these are fixed in the next public release coming out on Monday.
Alternatively, you may be trying to till a part of the farm you haven't purchased the rights to yet. This aspect is still under development. The upper right area of the farm is fully available to work however.