Fish emulsion. How and when to use it?
 

Well today I decided to buy some fish emulsion and I was wondering how I should use it. Should I use it by itself like an ordinary fertilizer, or should I use it just as a foliar spray, and if so, how often. Would it be okay to mix it with synthisized fertilizers, or would it explode or something?:biggrin: Thanks for any info!

I think you can do either one. I don't use fish emulsion but I do use Maxicrop Liquid Seaweed. I mix it in with my regular fertilizer. Since I grow outdoors my fertilizer gets on the leaves and in the pots. Some people just use it once a month as a foliar spray by it self. During the summer I use the strength recommended on the label but this time of year I use half the dose. If you're growing inside remember that fish emulsion really smells bad for a day or two.

I use a trace element fortified fish emulsion at 1/4 to 1/2 the recommended strength on the label for general garden plants, depending on the orchid. Based on Ray's calculator this comes to 150 to 75 ppm N. I use it instead of fertilizing with a synthetic fertilizer; I usually alternate between the two each week. Fish emulsion is a reasonably strong fertilizer so if you are going to add fish emulsion to a synthetic you will need to halve the concentration of each so you don't burn the plants.

Seaweed extract is generally thought of as a conditioner/tonic rather than a fertilizer per se and is not comparable to fish emulsion. Seaweed extract contains a variety of growth regulators but it has almost no nutritional benefit, so adding it to a synthetic fertiliser will not increase the total NPK that much and has little risk of burning your plants.

The seaweed typically has negligible N, whereas the fish emulsion is a high N fertilizer. so, in my opinion, really not comparable products.

I have heard that orchids really don't absorb from foliar application the way many other plants do. I doubt that it's harmful in any way, but personally I wouldn't make any kind of extra effort to get food on leaves.

Finally: fish emulsion is SO high in N that I make a point of making sure I am also giving sufficient P and K over time. Fish emulsion typically is 5-1-1, that's a very low P and K ratio. I actually don't use fish emulsion on anything but terrestrials and firbark-rooted orchids, as these mediums are the ones which really are known for having bacteria which eat substantial amounts of the N, so they (especially firbark) need high N applications in order for any N to make it up to the orchid.

Fish emulsion, being an animal product, can be caustic to orchid roots. If you use it, constantly check the roots for rot or burn.

Liquid seaweed, on the otherhand, being a vegetable product, is very gentle and good for roots. Seaweed can grow as much as a foot a day, and has lots of good micronutrients in it.