...by your obvious gardening skills. You must have outdone yourself with the amount of cotton you have used to embed the marigold though.
Cotton is easier to grow than most people realize. It is even grown in drought stricken California. Probably before the rovers have finished roving, indications will be found that cotton may have once grown on Mars.
Corn is another plant that is easier to grow than most might guess. With enough nutrients furnished by politics and subsidies, it can be grown almost anywhere.