Answer: Rinse the seaweed thoroughly, says Jim Stephens, Extension vegetable specialist at the University of Florida in Gainesville. Make piles of fresh seaweed about one foot tall by four feet wide on a surface that allows water to drain, but won't be affected by the salt, such as a gravel driveway. Rinse and turn the piles three to four times to wash out all excess salt. Spread the seaweed out and allow it to drive for two to three weeks. Then shred it or apply it directly as a three to four inch mulch. If you're using fertilizer, rinse it as described above, but skip the drying step and add it fresh to the pile, he explains. Seaweed is high in potassium and many minerals, and because it has little cellulose, it decomposes more quickly than hay or leaves. Rinsing will not remove significant amounts of its nutrients.
Q&A Library Searching Tips