Thankyou for your question and let me try to split it up into different sections.
Main Crop for Kenya [Nationally]
Maize, most of which is milled to make maize flour aka corn flour. In the home this is used to make 'ugali' which is part of nearly every meal in Kenya. The maize cob is also sold at the roadside roasted or can be stripped of the corn kernels and cooked with beans or peas and mixed with mashed potatoes.
Main Crops for Kenya [Commercial Export]
Tea
Coffee
Sisal [In decline due to poor processing infrastructure]
Roses - Grown in the Rift Valley [Naivasha]
