Many developing countries today are facing major challenges with regard to food security due to changes in rural land use, coupled with population pressure. One of the ways countries like Kenya has responded to this is by teaching agriculture at various levels of education especially secondary school level. Little has been done however; to establish whether there is any significant difference in agricultural productivity between farmers who graduate with secondary school agriculture knowledge and those without as a way of building farm capability hence the study. The sampling procedure adopted by this study was proportionate sampling technique, where a sub-sample of farmers from a target population of those farmers with secondary school agriculture knowledge and those without this knowledge and a total of 200 farmers where interviewed. Results show that farmers with secondary school agriculture knowledge perform significantly better than those without the secondary school agriculture knowledge and thus have higher levels of food security indicators in crop productivity, and level of household food security. It is concluded that farmers with secondary school agriculture knowledge perform significantly better in all farming aspects as compared to farmers without. The secondary school agriculture knowledge not only broadens farmers’ capacity, but also makes them more effective, self reliant, resourceful and capable of solving farming problems and as a result, significantly improves their crop productivity and hence guarantee food security for the family. The challenge for the teaching profession is finding out the best teaching methods as approaches both in and out of class.