Major and minor ticks
You can add minor ticks lines by adding a second axis and disabling the text labels.
<Plot grid inset={10}>
<AxisX />
<AxisX interval="1 month" text={false} tickSize={3} />
<AxisY />
<AxisY interval={5} text={false} tickSize={3} />
<Line data={aapl} x="Date" y="Close" />
</Plot>