To specify the date range of the NDVI time series you want, use the time parameter. Set it to a JSON object with three keys: start, end and unit.

start and end are date strings in the format yyyy-mm-dd, yyyy-dd or yyyy

unit is a string with a value of either day, week or month.

This example specifies daily NDVI between August 1, 2019 and February 28, 2022:

request = {
    'variable': ['ndvi.streambatch'],
    'space': [[-0.15974, 51.50776]],
    'time': {
        'start': '2019-08-01',
        'end': '2022-02-28',
        'unit': 'day'