Did the organic matter in the water wick up into the containers? Unless it was soluble instead of stuff that suspends in water I doubt it even made it into the mix.

You are correct that the plants can't use the nutrients until the microbes process it first. They *will* process it, but when/how quickly is anyone's guess.

Thanks, JAG. The seaweed extract is a brown liquid that mixes in with the water and turns it brown. The fish emulsion is a think and extremely stinky gray goo that seems to dissolve into solution as well. There wasn't a suspended layer on the top, so they both must be soluble...I am assuming.

Yes - watering it in from the top would have been better, but as noted, you don't know if the nutrients will be made available today or Memorial Day.

Al

Not so. Just because it appears soluble doesn't mean it is. What you have is a suspension of large organic molecules that cannot pass through cell walls until they are broken down into elemental form. The FE and SE will quickly fall out of suspension and settle to the bottom of the container & remain there until they are broken down (rot).

Al

Now that I'm thinking about this- why would the seaweed extract recommend a foliar spray application if the nutrients need to be broken down in the soil first before being absorbed?

Seaweed extracts usually are water soluble. Fish ferts usually are not, but some are.

In the case of the fish ferts it depends on the processing.

If your product is water soluble it should say so on the package.

A bit less reliable, but a fun, at home test is to mix a gallon of water with the recommended amount of product and leave it sit, unagitated overnight. If you see separation, you know it isn't soluble.

Always up for an experiment, I left a gallon of fish ferts overnight, and a sediment layer settled to the bottom. The seaweed extracts did not...and yes, it was fun!

JAG- Water soluble or not, if the seaweed extract still has to be processed in the soil by the microbes (because it is in organic form), it would seem to me that a foliar application would be useless.

Both inorganic and organic compounds can be water soluble, depending on the compound, of course. If a compound is water soluble, that doesn't necessarily mean it can pass through the plant's cell wall does it? I didn't think it came down to water solubility, and was more of a function of being permeable through the plant's cell wall... although my plant physiology is weak to non-existent these days.

Can you clarify?

Also, if a plant absorbs nutrients differently through its foliage versus the roots, then we have an entirely different discussion with regards to foliar feeding. :)

What you said is true. Plants can absorb nutrients in ionic form, but the larger organic molecules are unable to permeate cell walls whether they are soluble or not, so need to be acted upon by soil biota before they become available.

Some plants can absorb mineral nutrition via foliar applications. Water & its accompanying solutes are transported through the cuticle or epidermal cells of some leaves & twigs by diffusion, where it is adsorbed on the surface of plasmalemma (a kind of protoplasm that forms cell walls) where, by osmosis, it passes through cell membranes to cytoplasm. In some plants, water is taken in through open stomata as a secondary pathway. How much water can be absorbed through leaf & twig tissues varies by species, & within species, cultural conditions also have great influence on the process. Ambient temperature, relative humidity, leaf senescence (age), light intensity, nutritional status of the plant all have impact on how readily water is taken in through leaves & twigs. Using a surfactant (wetting agent) also facilitates diffusion. The primary factor creating a barrier to diffusion through leaf cuticle tissues is the amount of (epi)cuticular wax present in epidermal tissues.

In agronomic applications, generally only Fe, Mn, and sometimes Cu are applied as foliar nutritional sprays because the pathway via foliar application is often more efficient than the 'soil to roots' route.

Soluble salts present in foliar applications may or may not be available, depending on the plant, but the larger molecules are not - unless they are broken down on the surface and diffuse into tissues via the same pathway(s) as the already soluble minerals.

Do I get a grade? ;o)

Al

If I were qualified to give you one, it would be an A++!!

Thank you for the clarification, and I have to admit that I am rethinking my fertilization approach...though that is an entirely different topic and one that would likely spark some 'spirited' debate!

I top watered the rest of my seedlings with the fish emulsion and seaweed extract. Hardening off will begin soon, and I have to get a move on with buying some pine bark fines if I'm going to have my containers ready in time.

Thanks again!

I should be beaming then - and polishing an apple. ;o)

Al