I would think your tea would be stronger than organic ones. And weakness of the solution is what I gathered was the negative to using organic nutrient solutions. Though its not what you asked, I would think you could potentially use that tea as a nutrient solution.
As for using as a foliar spray, I personally would probably let it sit several days then simply skim liquid off the top to limit solids in the spray bottle and being deposited on the leaf surface. also, as a foliar spray, I don't think aeration is necessary (though it couldn't hurt)

Grizzy,

Thanks. What I read is if compost tea is not aerated, the microbes that make it work tend to die. I can strain the tea to make sure it will work in the sprayer I have - it's made to spray decks with and has some different heads I can attach depending on the liquid being used.

I also did a search of this forum and a lot of posts from a couple of years ago seem to think using it as the solution was not a good idea, but I think most of the people who replied were not using a DWC method.

If things go as planned, I will start my second season tomorrow - I have six tomato plants (four Legend and two Mira) to place in buckets, once I get the pH and ppm where I want. Within two weeks, I should have 28 plants growing, then add about another 20 plants over the following six weeks.

My nuits are not that much different from compost tea, though. I'm using tomato-tone (a dry fert that has some water soluble N and some that isn't water soluble) but also adding a small amount of fish emulsion and then a couple of ground up female multivitamins - the female ones have iron! I also aerate this for 36-48 hours, which helps to dissolve most of the stuff.

One thing that I learned was to mix everything in a container than add it the buckets. So I got a 32-gallon plastic garbage can that stuff goes in and then gets added as needed to each individual container.

My choice of plants to start with are Siletz, Legend, Red Delicious, Mira, Sacramento, Florida 91 and IT-06-313. I haven't tried growing anything in a GH or done much with hydro, but in the dirt, I had about five good weeks of harvest. If I trim the bottom leaves, keep temps level and keep a close eye on the ppm and pH, I'm wondering if I can get eight weeks from most of them?

Without making things too complicated, what I need is six ripe tomatoes per plant per week - on average. My dirt experience says this should be a piece of cake, once the plants get mature and the fruit starts ripening. My hydro experience says ???

Mike

Grizzman,

An update - I only started three plants tonight. I want to make sure they don't kick the bucket before I use up the seedlings I have ready. My solution in aerated water that has tomato-tone (last year's version) with fish emulsion added. The ppm is only about 650 at this time but I want to get it up to about 1500 once the plants start growing (which hopefully they will!).

On a possibly good note, we are not forecast to have lots of sun until Sunday. The plants have been in the GH for three weeks or so, so they are hardened off, but any transplant is a shock.

I raised the seedlings in potting mix - they are big enough to stick in dirt in spring. Don't know if this is better or worse than using rockwool but at least I have good seedlings to start with.

Hopefully, pics of growing plants to come in a few weeks!

Mike

Hi Mike,
The use of compost tea as a foliar spray isn't causing any harm if applied by the book (reliable recipes). But most scientific studies claim that there is little beneficial effect or benefit in terms of actual nutrition. As we know, the main nutrition uptake is by root osmosis and only little can actually be absorbed through the foliar structure (for most plants). Beneficial micro organisms made from matured compost seem to be an exception, - but they have a protective function (make plants more resistant) and do not affect nutrition much either. But in this case it's very important to use matured compost, as beneficial micro organism only build up and dominate in compost over time.

Some deficiencies (of immobile element) can be treated effectively by foliar spray. But in this case also, research has shown that it is way better to insure this part by a balanced nutrient solution in the first place.

My conclusion: foliar spray is fine for any sort of treatment and can be seen as an occasional supplemental nutrition, but still plays a minor role for the general nutrition. In other terms: it is actually overrated by some!

PS: some specific plants may take much more advantage of foliar sprays of compost tea than others... (orchids for example), it may be worth to have a closer look at this particular aspect of the deal!

I'm not looking up sources right now, but I will share some of what I have read in the past in general. One is what lucas_formulas said about studies and little or no benefit of foliar spray of compost teas.

Two, I've read before that if you don't use well finished compost from a hot compost operation you can actually damage your plants if the compost contains spores of disease causing fungi or bacteria. Pretty much makes 100% sense to me.

Three, there is some concern that teas actually help to breed pathogens that can harm humans. One of these is E. Coli. E. Coli is on lots of our food. It is one reason we should be washing. We often eat bad microbes in small amounts and this is okay thanks to our immune systems. But, when you put that pathogen in an environment of ideal conditions you may just be breeding it rather than killing it. That one is supported by the Rodale Institute, if you need a lead on where to find more info. There is a reason that most of the E. Coli and Salmonella outbreaks have been from organic sources.

Four (really just number one explained), the reason for aeration is to promote aerobic microbes as opposed to the stinky anaerobes and hypoxics (low oxygen loving), which do you no good once you spray them on a plant since they die off. In theory, the aerobic microbes will dominate the leaf's surface area and keep bad microbes from infecting the plant as long as they are around. Studies from a couple universities have shown little truth in that, though. The fact is, if you spray a plant in the day, the UV will kill the microbes fairly fast (which is why you don't leave your tea in direct sunlight in the first place). Even most compost tea promoting books acknowledge that like Teaming with Microbes. Indoors, that may not be so much an issue. I don't know for sure. The most benefit from teas is really in the root zone from what I have gathered. I use them religiously, but only from worm castings and only for dirt. The compost goes on my garden.

The answer to the problems with substances or organisms that are UV-sensitive is simple. A. if supposed to be active at the foliar surface, they need to be applied daily or 3-4 times a week (in the right dose). Azadirachta (azadirachtin) products are also supposed to loose their effectiveness due to UV (as some claim) in around 24h. Here the same technique applies.

B. any substances or organisms that are supposed to be absorbed by-, and hence in some way active IN -a plant, are equally exposed to UV at their 'final destination'. As they become part of the plant's biochemistry, it actually doesn't matter if they were absorbed by root-osmosis or applied as foliar spray once. They are anyway supposed to be direct nutrients, or helping producing enzymes, having a antibiotic function or helping with toxin elimination, etc.

HYDROPONICS only: because compost 'teas' that contain wanted microorganisms may not be well supported in a nutrient solution and/or may causing PH- or other troubles, if added - it might indeed be a good idea to apply them as foliar sprays.