Google charts - delete gridline for first of month

Question

Same issue with scattercharts and linecharts. Have a working chart, vAxis - sensor readings, hAxis - datetime. Chart shows daily readings for the last eight weeks - works.

And what it looks like, unwanted gridlines for the first of the month:

I have hAxis gridlines set up to display every 7 days - that works, but in addition to the weekly gridlines, google charts insists on displaying gridlines for the first of the month. Tried every permutation of gridlines count and minor gridlines I can think of. The only success I have had is gridlines color none, but that turns off all hAxis gridlines.

How can I turn off the gridlines showing for the 1st of each month?

Relevant options:

var levelOptions = {
title: "Remaining",
width: 420,   //column is 420 with padding 5px, but this gives a right
//margin the same as the left
height: 250,
// chart area needs to be less than 100% to make room for axis labels
chartArea: {width: '85%', height: '80%'},
titlePosition: 'in',
axisTitlesPosition: 'none',
titleTextStyle: {color: 'DimGray',
fontSize: 14,
bold: false},
curveType: 'function',
lineWidth: 2, //width of lines connecting points
pointsVisible: false,
vAxis: {minValue: 0, //no need for max value, calc automatically
gridlines: {color:'Gainsboro'},
baselineColor: 'DimGray',
baseline: 0},
//Gridlines: {count: 0}, does nothing
//minorGridlines: {count: 0}, gets rid of all gridlines except 1st of month
//but leaves the ticklabels there, so why does gridlines count = 0 not work
//gridlines: {color:'none',}, //this gets rid of all of them but
//adding back in minor grid colour does not put them back
hAxis: {ticks: ticklabels,
textStyle : {fontSize: 9},
gridlines: {count: 0,},
//minorgridlines: {color:'Gainsboro',},
//gridlines: 0,
format: 'dd MMM', //so dates appear as, e.g. 1 Apr
baselineColor: 'DimGray',
baseline: data.getColumnRange(2).min},
legend: 'none',
};

ticklabels is an array of dates generated by parsing the arrayData and picking every 7th date.