What items was the farm running out of by the summertime?

From the text:

Nevertheless, as the summer wore on, various unforeseen shortages began to  make them selves felt. There was need of paraffin oil, nails, string, dog biscuits, and iron for the horses' shoes, none of which could be produced  on the farm. Later there would also be need for seeds and artificial  manures, besides various tools and, finally, the machinery for the windmill.