Wairimu and her family eat three times a day, but some families only eat once a day or less. In 1987, a study by Mazingira Institute found that almost one in three of urban households in Kenya farm crops in town. However, while middle income earners can grow food in their backyards, low income earners lack space and farm on public land when they can find any. The average size of an urban farmer's plot in the capital, Nairobi, was tiny, under 100 square metres, less than a quarter of the size of those in smaller towns. In general the larger the town, the more organic inputs are used.
Most urban farmers are too poor to buy fertilizers.
However, the most important input is water, more easily obtainable in towns than rural areas, and used by two thirds of urban farmers in Nairobi. Wairimu Kinuthia tending her plot of land Manure is used by one third of urban farmers in Nairobi and about the same proportion use compost which they produce themselves, but a few exchange compost through informal barter or gift from friends. Compost is even sold on the market. Manure is also exchanged through barter or gift between livestock keepers and crop farmers in Nairobi. Other inputs like mulch and chicken droppings are used as well.