Generally, the frequency recommended for fertilizing any seasonal plant in a container is "weekly weakly". Since worm casting tea is a relatively dilute solution anyway, this kind of schedule seems very reasonable.

I would do the same for seasonal plants in the ground. The herbs need no fertilization (and would prefer none as well). The roses you can stretch out to every month to 6 weeks or so.

Agree with "weekly weakly" and it usually refers to 1/2 stregth dilutions. If you dilute it to 1/4 strength you could theoretically use it every time you water containers though given how long it retains effectiveness I wouldn't think it would be needed that often.

Some commercial worm castings products I have tried recommended full strength dose monthly but I have found the diluted form weekly to be more effective especially until the plants get well established.

Dave

How often depends on what your plants need. Plants growing in a good healthy soil would never need to be sprayed with any teas while plants growing is soils lacking adequate nutrients will need the addition of most all nutrients.
Look at the plants. Are they thriving and producing as expected? They do not need supplemental fertilization. Are they not thriving and producing? Then they do.
To simply add some fertilizer, especially if not needed, can create more problems then it will fix.

This post was edited by kimmsr on Mon, Apr 28, 14 at 6:33

Tea really isn't a fertilizer, and can be applied every watering, though that is unnecessary. Every 2-3 weeks is sufficient, though it is best to get a better understanding of what it is intended for.

microbeorganics.com

Worm tea may not be marketed as a fertilizer but it certainly IS one, just as compost or manure teas are a great organic source of plant nutrients. The big bonus with worm castings is the excellent array of trace elements it contains. And for any containerized or seasonal plants, the "weekly weakly" program is entirely justified - ALL nutrients must be provided from outside in the case of containerized plants and routine supplementation is typically suggested for seasonal plants to maximize flowering or fruiting in their short growing season. You would drown the plants before you would come anywhere close to overdoing with worm tea.

Here is an example of the percentages and composition of nutrients and minerals in vermicompost and by translation, in worm tea.

⢠Organic Carbon 20.43 -- 30.31 %
⢠Nitrogen 1.80 -- 2.05 %
⢠Phosphorus 1.32 -- 1.93 %
⢠Potassium 1.28 -- 1.50 %
⢠Carbon : Nitrogen 14-15 : 1 %
⢠Calcium 3.0 -- 4.5 %
⢠Magnesium 0.4 -- 0.7 %
⢠Sodium 0.02 -- 0.30 %
⢠Sulphur Traces to 0.40 %
⢠Iron 0.3 -- 0.7 %
⢠Zinc 0.028 -- 0.036 %
⢠Manganese Traces to 0.40 %
⢠Copper 0.0027 -- 0.0123 %
⢠Boron 0.0034 -- 0.0075 %
⢠Aluminium Traces to 0.071 %
⢠Cobalt, Molybdenum Present in available form

The above is approximate only, noting that all vermicompost is different because the composition does truly depend on the type of feed you give to the worms. But the above table does show the range of nutrients available in this product and confirms its position as an excellent source of plant nutrients, aka a fertilizer.

I dont consider worm tea a fert. but more of an immune re-enforcer if you will. Microbes that are sprayed on leaves on a regular interval weekly or bi weekly could and should help any plant. But if that plant is exceedingly healthful to begin with you would never notice a change. What you spray on the leaves will be sent to the roots quicker than a drench no matter what you think.
Another thought with using castings and Im assuming you have access to fresh as I do, is its the quality of the castings used that can really make a difference. I have a factory 360 hardly ever getting any leachate drainage , which should not be associate with worm tea in my book. So as I have 5 trays going at present with the top tray used with only dry shedded paper to deter fruit flies, I like to take any vermicasts that have fallen in the drain pan[the same pan for any liquid drainage catchall. Any vermicasts there will look like coffee grounds and that my friends will be the best stuff you can use to make worm tea. Im usually able to scrape up about 2 cups of pure castings in that tray for said use.

100% yes to what HummerSteve said. Have you said yet what you mean by "worm casting tea?" True, leachate drain-off is not at all the same thing as the "worm compost tea," which is typically brewed from the castings themselves, dechlorinated water, and ideally an air pump and a pinch of a couple other things (usually Fish Hydrolysate & Molasses, and sometimes kelp & alfalfa meal.) Is that what you are doing? The leachate, if it smells ok, should have some usable nutrients, but it's not tea. There are actually several practices in between leachate and aerated compost tea (ACT), which are really well defined here:

Gardening with Microbes: It's Tea Time! (by Tad Hussey) http://www.gardeningwithmicrobes.com/teaarticle.shtml and http://www.gardeningwithmicrobes.com/teaarticle2.shtml.

If you are brewing a really good aerated worm compost tea for it's microbes, twice a season is sufficient unless you see disease, but you cannot over do it, since it will not burn your plants. Some people brew tea twice a month and have a very LIVE soil. However, if you have a soil rich in fungae, bacteria, nematodes and protazoa, you will not need to add "fertilizer," because the roots will eat their soluble nutrients from the waste of these microbes. (I know this is really simplifying.) At least, that's my understanding from reading about it.