A greenhouse holds heat and humidity steady for months while a crop grows. Mariami dates never see anything like that in the field — they're grown in Iran's Bam and Jiroft basins, open desert heat with none of the moisture a greenhouse is built to trap. The climate-control problem for Mariami shows up later, after harvest, in the grading room.
Mariami is one of the softer, oilier varieties on the market — closer in texture to a moist Mazafati than to a firm Deglet Noor. That softness is exactly what makes the sorting stage risky. Fruit graded and packed in a humid room picks up surface moisture fast, and a soft date that's already high in natural sugar and moisture will start showing mould or fermentation within days if the room isn't controlled the other way from a greenhouse — dry, not humid.
Why a grading room is the opposite of a greenhouse
A greenhouse exists to keep humidity IN for a growing plant. A date grading facility exists to keep humidity OUT of already-harvested fruit while workers sort by size, colour and skin condition. Same word, "climate control," opposite direction. Bam's grading houses run dehumidifiers and keep fruit moving through sorting quickly rather than letting trays sit — the harder Mariami grades tolerate a slower pace; the softer AA and jumbo grades don't.
What that means once it reaches Malaysia
By the time Mariami lands here, most of that risk is behind it, but the same logic applies to how it's kept before sale — a sealed container in a dry cupboard, not left open in a humid kitchen. If you're comparing grades, the texture differences are covered in more depth in our piece on Kurma Mariami AA, and the broader cultivation side — including how growers now monitor these conditions — is in Harga Kurma: Technology's Role in Date Palm Cultivation. For sourcing, Date Wholesale Green Diamond works directly with growers who take the grading stage as seriously as the harvest itself.