Container Garden

My farm is half a mile away from where I live, and I'm now confined to the house for huge chunks of time on nursing duties for the foreseeable future.  I'm getting cabin fever, and the work at the farm is getting a bit too much for my other half and things like seed raising and propagating are getting neglected.  So, having finally caught on my sleep after months of being up half the night every night, I've taken the bull by the horns, cleared out the old chicken run at the house, converted it into a shade tunnel and am setting up a container garden to supply herbs and salads for the house, and raise young plants for the farm.  The back yard is small and paved, but uncle's bedroom overlooks it so he's quite happy when I'm out there as he knows I'm close by, so I get to play out there as much as I like. 

At the moment I'm just using potting compost bought from the local agri merchant, but the general plan is to start using partially rotted donkey maure to grow agaricus button mushrooms on, then use the mushroom compost to grow the plants in.  I have to add a fair bit of calcium to the manure for the mushrooms, and I'm not sure if this is going to effect what plants I can grow in it afterwards?  In particular, I'm hoping to raise a lot of blueberry plants which are supposed to prefer acidic soil. 

What I really want to know is does anyone out there have experience of using mushroom compost as potting compost?  Do I have to do anything to it before using it?  I'm assuming I'm going to have to add something to keep the fertility of the potting compost up but would prefer to use organic, sustainable methods - any tips?  I can buy pelleted composted manure (much stronger and easier to handle than my donkey manure) cheaply which I can mix in with the potting compost and can sprinkle on top every now and then - is that going to be enough?  I thought of using urine, but I don't fancy it on the herbs and salads and even on the other stuff I'm concerned that it might not be balanced, or be too strong or salty or something, for use in containers.  Is there anything else I could use?  I know people buy 'liquid seaweed', maybe I could make up something like that out of weeds if someone has a recipe and knows how to use it? 

Any tips, ideas, comments welcomed!

No replies yet, but I've been researching organic fertlisation for potted plants and discovered that most forums consider it's not possible and that any evidence to the contrary is purely anecdotal.  The theory seems to be that the microbe population in the potting compost can't be maintained within a container because temperature and moisture fluctuations are too great, and without the microbes it's not possible to use organic fertilisers as they are needed to mobilise the nutrients into a form the plants can use. 

Pah.  There's no way you can convince me it's not possible so I hit google.  The first interesting thing I found was http://www.scientificamerican.com/blog/60-second-science/post.cfm?id=p-is-for-plants-human-urine-plus-as-2009-09-04

"Gardeners, take note: the secret to growing hearty tomatoes is remarkably close at hand. Look no further than your fireplace and, er, your bladder.

According to a study from a group of environmental scientists at the University of Kuopio in Finland, human urine and wood ash make a reasonably potent tomato fertilizer, boosting plant growth and fruit yield dramatically over untreated plants and nearly keeping pace with conventional fertilizer. The research appears in the August 26 Journal of Agricultural and Food Chemistry.

The idea did not come completely out of left field—urine and ash have individually found use in helping plants grow, and their beneficial aspects appear complementary on paper. A commonly used nitrogenous fertilizer called urea is prevalent in urine, and wood ash (the Finnish group used birch) is rich in nutrients, such as potassium and calcium, that urine lacks.

In the greenhouse test, urine alone actually produced more tomatoes than urine with ash did—and neither treatment produced quite as much as did the researchers' mineral fertilizer. But both urine-based fertilizers roughly quadrupled fruit production when compared to unfertilized control plants. The researchers estimate that the product of a single individual's micturition could fertilize 6,300 tomato plants a year, yielding more than two tons of fruit.

The addition of ash did confer some benefits—those plants were larger and grew fruit with significantly higher magnesium and potassium content. A panel of 20 taste testers rated all growing methods as equally tasty."

So it *is* possible!

Then, after more googling and finding about fifty variations on the same article, I stumbled on this link to a 15 page pdf on The Usefulness of Urine  http://www.ecosanres.org/pdf_files/PM_Report/Chapter_10_The_usefulness_of_urine_a.pdf

This pdf is an absolute gem!!!  It goes into the science of using pee on container plants, then gives loads of info and photos about how to collect, use it and balance it with other ingredients to grow tomatoes, mulberry cuttings, corn and other crops.  The work was done in Africa using ordinary soil as the potting medium.

So it *is* possible!  I don't actually have any spare soil for my containers, so I'll probably experiment with aerated compost tea to put some microbes into the potting compost before starting to add urine and then use regular doses of tea to keep the microbe level topped up.

I'll let you know how I get on.