Knapp gave him a list of simple innovations to follow things like deeper plowing and better soil preparation, the use of only the best seed, the liberal application of fertilizer, and more thorough cultivation to remove weeds and aerate the soil around the plants.

NEWYORKER: Testing, Testing

It looked at vegetables such as carrots, lettuce and spring onions which were grown close to or in contact with the soil and which were sold to be consumed without any further cooking or preparation other than light washing or scraping.

BBC: Carrots