Question
Hi.
 1. I heard about using fresh seaweed for fertilizing- can i use it for perennials and evergreens in my garden?   can i put it as mulch in fall or how early in spring? how often to reapply?
 2. We live on Cape Cod,MA.  Spring and early summer are usually  very wet here. All the organic products that I've seen so far needed to be reapplied after each rain- we have to kill Gypsy moth on everything, thrips on many flowering trees and some roses... And then there are different kind of fungi in late summer- from black spot and mildew to specific wilts and rusts.... Is there anything organic that can help with those problems- especially Gypsy moth- without reapplying it every time than it rains?

Answer
Q #1: Your concerns about Seaweed probably surround the p.r. about heavy metals and contaminants they soak up, with alarming efficiency, and may deposit in your Soil.  Probably founded.  Whether contaminants bind to your Soil and stay there depends on the metal or contaminant, the composition of your Soil, and the purity (or not) of the water you harvest your Seaweed from.  Take your proposed Seaweed Samples down to a Cooperative Extension agent and see if there is a local facility that has already done that work.  There are a LOT of potential pollutants, especially in a community like Cape Cod.  But there may be nothing to worry about.  Find out.

If you're not going to grow Tomatoes or Watermelons in your Soil, there would be cause for concern to the extent that your Soil could build up these chemicals over time, or leach them if your Soil is very Sandy.

I'd start with the Seaweed.  It's very good for Soil and Compost.  I could go on; let me know if you need more information.

Q #2: 'Organic' isn't limited to non-toxic Green Bug- and Fungus-killers.  Discover the joys of IPM -- Integrated Pest Management.  This is the ultimate control for evil forces in the Garden.

Take the Gypsy Moths you're dealing with.  You don't HAVE to fight Lepidoptera lymantriidae with short-lived, broad-spectrum 'Organic' products.  Besides, what about the collateral damage to beneficial insects?  Why wipe out all your friends just to get the Gypsy Moths?  That does not work for you.

Consider, instead, Bt-booster Zwittermicin A.  This antibiotic, discovered by a University of Wisconsin-Madison Plant Pathology professor, was later found to transform caterpiller-crushing Bacillus thuringiensis from a mere fatal illness developed almost 50 years ago into a VERY deadly, VERY incurable, utterly inescapable modern biopesticide, described in the Feb 2000 issue of Environmental Entomology:

execdeanagriculture.rutgers.edu/pdfs/goodman-072.pdf

Simply, Bt treated with Zwittermicin apparently kill more Gypsy Moths.  Zwittermicin itself does not harm Moths.  But mix it with Bt and you have a major weapon of biological warfare.  Lots of people are happy about this, because they have noticed that some targeted insect pests are showings signs of resistance to the 125 insecticides on the market that are based on Bt.  This not only turns it up a notch, but transforms it into a solution that is even stronger than before.

Gypsy Moths are getting harder to control for another reason.  Research in 2007 found that Birds don't like the flavor of Gypsy Moth caterpillers as much as they used to.  Seems the leaves favored by the caterpillers build up sour-tasting Phenolics and Tannins when they're around too much Carbon dioxide.  When the caterpillers eat the leaves, they start to taste toxic to the Birds, which reject them in favor of other, tastier protein sources.

That's bad news for Oak Trees, the top host of this pest, and the hundreds of other Trees defoliated in a good Gypsy Moth season.  So there's all kinds of funding to discover newer, better Gypsy Moth controls.  Get out there and deploy some of them.  They're easy to buy and a breeze to use.

What are you using for the Thrips and other insects?  What are you using for the Gypsy Moths?

Fungi are a large and complex area.  Mildew on one is a different species from Mildew on others.  Which plants do you find are under attack, and what do you think is the name of the attacker?

Finally, just to get this out of the way, are you absolutely certain no one, including you, has used any broad spectrum Pesticide, Fungicide or Weedkiller at any time during the year in the plot you are dealing with?

THE LONG ISLAND GARDENER