You should try lyophilization

We only perform airdrying in our lab for plants and even seaweeds. We try to get away from oven drying or sun drying to preserve several metabolites which can have potent biological activities.

you can put your samples to a cold air current. it facilitates the evaporation of water without causing the growth of fungus and bacteria.

Dear Danrev

Drying methods depends on your analysis. If u want to analyze Antimicrobial then u have  to dry it in shed or in absence of light in low temperature. As many phytochemicals present in plant which having antimicrobial properties are heat labile!! But if you want to study many biochemical properties then you can dry it in hot air oven in low temperature in between 40-45oC. Try it if any more information required please tell me....

Try use the hot air flow container, you can made it with wooden case box with exhaust and head lamp (Modified aparatus regard to Dr. Priyanka Roy explanation)

It's depend on know much sample willing to be process and your climate. We used 2 method for normal preparation: 1. air drying, in the room (no direct sunlight); 2. direct sun-drying with black fabric above the sample tray. As we live in tropical area, we have sunlight for about 12 hours, daily.

Please be aware on the drying rate vs mold growth.

Question; why don't you directly process the wet sample? make a juice of it and do the solvent partition

I think it's better to use airdrying for plants if your aim is the analyze of petrochemical constituents and it's better to put it away from sun light and this to concerve several metabolites which can have potent biological activities.

Always prefer drying in shade using hot air currents (not more than 40 degree temp). But keep in mind the climatic conditions for ex. fungal or mold growth occurs rapidly during rainy/humid season.

As your plant material is watery, natural drying will take more time and also there is possibility of fungus/ bacterial formation. Hence, lyophilization method is preferable   for drying for your plant material.

Make sure that you chop your plant material into small pieces and then dry it in a shade in front of a fan to preserve all the chemicals and to avoid any spread of fungi and bacteria

Freeze drying

You can also air dry , but this depends on the water content of the material. Lyophilization could also be useful.

Hope this helps? 

Lyophilization