Originally Posted by Richard

Seaweed extract is a good way to provide your plants with micronutrients and various organic compounds, but with a few caveats:

• Kelp extract can react with several compounds commonly found in soil and composting material. With reasonable dosages of extract, this is not a problem and sometimes actually beneficial. However, too much seaweed extract can produce reactants that are very acidic and your soil pH will drop below 5.
• Some manufacturers of seaweed extract (mostly small-time operators) do not balance the chemistry of the extract for plants. This can cause many undesired side effects. For more details: Micronutrients

Grow More has a product line of chelated (liquified) micronutrients called "Fert-All". There are many formulas of Fert-All, but one of them is called GP, short for General-Purpose. The chelating agent is natural Ligno-sulfate extracted from wood, and the micronutrients are all extracted from sea kelp. The ligno-sulfate is immediately absorbed by plants along with the micronutrients -- hence the product is very efficient. Since it is completely produced from natural materials without synthetics it is approved for certified organic farming in California. Strangely enough, it is also less expensive than seaweed extract.