Monsoon and Drying: Planning Seaweed Supply Around the Weather

Seaweed can keep growing through the rainy season. What the rain interrupts is drying, and drying is where the value of a harvest is either kept or lost. A buyer who plans purchases as if dried seaweed arrives at an even rate all year will sooner or later be caught short, or will accept lots that were dried in poor conditions. Planning around the weather is part of sourcing, not an afterthought.

Why the wet season is a drying problem

Most smallholder seaweed in Indonesia is dried in the open: on platforms, nets, tarpaulins or racks, under the sun and wind. In settled weather this works well. When rain comes in bursts, or cloud cover lasts for days, several things go wrong at once:

• Drying takes longer, so the seaweed sits damp for more time and can start to ferment or discolour.
• Rain on partly dried seaweed washes out salt unevenly and can leach some of the useful material.
• Farmers under pressure to sell may bag seaweed before it is properly dry, which raises moisture and the risk of mould in storage.
• Seaweed dried on the ground in wet conditions picks up more sand and dirt.

None of these problems are visible from a price list. They show up later, as higher moisture, lower yield or a lot that deteriorates in the warehouse. Our article on why drying decides the price explains the link between drying and value in more depth.

How the seasons work in Sulawesi, in general terms

Sulawesi has a wet season and a dry season driven by the monsoon winds, but the timing is not the same everywhere. On the west coast of South Sulawesi, around Makassar and Takalar, the heaviest rain generally comes with the westerly monsoon around the turn of the year. Parts of the east coast, facing the Gulf of Bone, tend to have their wettest period at a different time. Central Sulawesi has its own local patterns again.

This matters because a supplier drawing on farmer groups in more than one area can sometimes balance supply across seasons. It also means that general statements about “the rainy season in Indonesia” are of limited use; the relevant question is which coast, and which months, a specific lot comes from. Year-to-year variation is real as well, and unusual weather can shift the pattern. Our overview of seasons, disease and climate risk covers the wider picture.

What better drying and storage can change

Weather cannot be controlled, but its effect on quality can be reduced. Raised drying platforms keep seaweed off sand and let air circulate. Covered or semi-covered drying structures allow drying to continue through showers. Dry storage close to the farms means that seaweed dried in a good week does not have to be sold immediately, and can be held and released in an orderly way. This is one reason covered drying houses and warehousing have become a focus of investment in seaweed communities.

Planning purchases: do and don’t

For buyers, the practical response is to treat seasonality as a planning input:

• Do ask each supplier which areas their seaweed comes from and when drying is hardest there.
• Do build stock ahead of the difficult months rather than buying from hand to mouth.
• Do agree moisture limits and testing in the contract, so wet-season lots are judged on the same basis.
• Do consider longer-term agreements that give suppliers a reason to hold quality stock for you.
• Don’t assume a spot price in a good month will be available in a bad one.
• Don’t accept a lot without checking how long it has been stored and in what conditions.
• Don’t push suppliers for fast shipment in the middle of a wet spell; that is how under-dried seaweed gets bagged.

The contract side of this is covered in our piece on moisture content and contract limits.

Frequently asked questions

Working with Kospermindo

Kospermindo has a warehouse in the Makassar Industrial Estate (KIMA), and in 2026 signed a cooperation agreement as a winner of the Madaya Sustainable Fund for a UV-plastic smart drying house programme. Read about our warehouse or contact us to plan supply.