Raised garden Beds

I have raised garden beds in a community food garden which we are trying to renovate/ regenerate.

How they were-
The soil in these beds, texture was good but there were no worms to be seen. Plants were small and struggling. These beds are an assortment of heights from 20 to 80cm high and are 12 in total number. They are not ideal in that the size is 3mX3m which means they get walked on IF need be. We have put walkways into them.

What has been done-
Knowing they need organic matter and compost I have done this to all the beds with varying results but all not giving me what I am looking for. All beds have had compost, by the wheel barrow loads and pelletised poultry manure added to them, and in the off season we have grown green manure crops and incorporated this also. Weeds are cut below ground level and dropped straight on the soils or mulch. The tallest beds have had compost, coir and pelletised poultry manure and these beds have had it incorporated i.e dug in. This was done last winter and were planted out this season with eggplants and more compost. Results, yes the eggplant is growing but they are not as strong and healthy as I would have thougth they should be.

We have now got worms in all beds, not in great numbers but you cn now find them fairly easily, that pleased me no end, but besides the bed which was dug to incorporate the coir and compost and manure the plants in the other beds are struggling. My question is with soil this poor-
1) is it possible all the nutrient we are adding is leaching to the lower levels and it is only going to take time to get this right.
2) is there a way I can speed this process up because this is a garden from which we want to feed the needy in this community and right now it would not feed a family.
3) how often should I be adding extra fertiliser through the growing season?  

So need some advice as to what I am doing wrong here. Please help  

Many things come to mind when reading your thread.

Those beds are definitely awkwardly big.  What sort of walkways did you build?  

Leaching is an issue with too much irrigation or rain.  

Did all the soil come from the same place?  

What was it's history before you got involved with it?

Could there be chemical contaminants?

What is the strata that the beds are sitting on top of?

Have you tested the soil for mineral deficiencies or ph?

Which green manure crops did you use?

How well did the green manure grow?  This might give an indication as to what it needs.

What is the mulch you mention?  

What was the form of the coir?  If it was too course and was mixed in, it could be robbing your soil of nitrogen and other nutrients necessary for plant growth.

 

hank you Roberto pokachinni for taking the time to reply and so quickly also.
I hope I have answered all your questions.

Walkways were constructed out of old bricks we had laying around.

I am not so sure the irrigation is a problem and rain… well we have not had a lot of that this year at all.

Soil was in place and had been there for about 7 years before we inherited. Crops had been grown in it and I strongly suspect chemical fertilisers used.

Beds were created from scratch and I doubt there would have been chemical contamination involved as the area was the back of a church.

Beds are sitting on bare ground there was no asphalt there.

pH 6

The mix I bought from the local produce store and it had a mixture of seeds in it.

It did not grow as well as I would have thought it should have. However, we were away through a lot of last winter and we turned off the watering system and left it to rainfall which did nto eventuate. So this has been a problem.
Mulch is organic sugar cane mulch.

The coir we bought in a block for the be rehydrated before incorporation. However, that maybe a an interesting thought to be looked at next time I expand a block I shall look at it more closely.

Hello Judy,

Given all the things you've already done, it's likely to be a soil pH issue - have you got a test kit?

A pH of 6 is too acidic for most vegetables. Needs to be 7-7.5. Soil pH isn't a linear measurement so it can be tricky. Soil pH affects the uptake of nutrients and makes others toxic to plants.

Lesser reasons could include a mix of:

The garden beds disturbed too frequently will put earthworms off, particularly if there's other food sources available to them - this includes digging the beds too deep, they only need to be cultivated about a spade depth.

Soil temperature can be an issue. About 25 C is best for most things.

Constant moisture - not too wet, not to dry - the 'Goldilocks' zone.

Some people will probably suggest woodchips, charcoal, and inoculation with mushrooms, but it seems you have sufficient organic material - the woodchips may assist with aeration and moisture holding capacity if the soil isn't sufficiently friable.

Mulch - I too use sugar cane, it's the best!

I've never used coir, but I have a feeling that it is high in carbon.  That was my thinking.  It will draw nitrogen into it.  Microbes need nitrogen to make carbon into useful soil.  Left as a mulch on the surface, no problem, or at least very minimal, but mixed in, high carbon substances can cause nitrogen deficiencies.

You need a certain amount of consistent moisture in your soil system to ensure growth.

It's difficult to guess as to what is wrong.

Chemicals (even chemical fertilizers)  can play nasty games with microbial communities, and plant uptake of nutrients.

It could be that a lot more organic matter in the form of compost needs to be added to the surface layers, and some compost tea might be beneficial in order to get the microbial community to grow to necessary proportions.

I have always found that soil pH between 6.0 and 7.0 is safe for vegetable gardens.

I agree that the coir could be tying up nitrogen.

I also agree that it would be safe to add quite a bit more compost, and perhaps a source of minerals (source might depend on where you are located).

Best of luck next growing season! If chemical residues are still present, things will be sure to improve :)

PH is likely not the problem, we grow in 5.6-5.8 soil and grow all kinds of veggies well.
My guess would be a trace mineral deficiency or imbalance. If you can swing a soil test that could tell you a lot. Or you could just apply a broad spectrum trace mineral supplement like glacial rrock dust or azomite. Without a soil test you're sort of just throwing things against a wall and seeing what sticks. It could be something simple but unusual like a copper deficiency but you can only really guess without a soil test

Well I so totally agree it IS hard to know what is going wrong here, I have tried everything I can think of. Maybe the coir, will double check the pH tomorrow when I am there but Elaine Ingham is not phased about pH and comments it are teh soil microbes which matter most. To that end I am thinking some rock dust, which I am going to have to pay for and 1 repeat one only does of molasses. Any thoughts??

I think the fog has finally cleared and after addressing all the obvious failings of these beds Yesterday as I was removing vegetation to replace it with a green manure crop for winter I discovered roots and more roots. It is apparent that these beds have been having the goodness and water sucked out of them by an ancient Golden Elm tree or possibly an almost equally old Liquid Amber. Ok I read root barier here however I am concerned if I put in a root barrier of Geo Fabric the roots will grow to under the barrier and just suck from there. Plus we are not talking  1 or 2 beds we are talking 20 beds, all will have to have this done. Am I correct or not and what other suggestions can someone please make.

Man, I was just going to ask you what kind of trees were nearby.  I have juniper cedars that send roots 25' from the tree and turn the soil to dust.

I made wicking beds mainly to keep roots out.  I took videos on the success and mistakes I made.

- TheRainHarvester on YouTube

Chris,
these beds are in a Community Garden which feed the needy of our community. I doubt they would have the money to convert all these beds into wicking beds. I made wicking back in 2009 and are wondering if even a double layer of Builder's Plastic would keep these roots out for very long. Almost 2 years ago I had these beds dug out to a depth of about 40 cm and these roots have grown since then. I only discovered these roots as I used my Asian hoe and started grabbing fiberous roots and when I investigated and dug deeper I discovered these roots down at the 40 cm height and they are 1/2 inch thick. Do you think that Builders Plastic even 2 layers ?

Oh, yes, I do.  In fact it is almost the method I used for my modified wicking beds (I should have said "modified wicking bed earlier" - sorry! ) .  I don't do gravel or fabric at all!  I do a single small pipe that is adjustable to set the water level.  But, being in hot central Texas, even that is largely unnecessary so far (and they actually do better)!

I forget the thickness I used, but it's in the construction video.  I used 2 layers. No roots have poked through.  But, like I show, be sure to add extra on the sides (a mistake I made).

What zone is the garden in? Hot, dry, cool, rainy?

Chris,
thanks for the reply. The things which are going through my mind ATM are, these beds are in a garden, yeah 25 feet from the main tree, easy. There are other beds on the opposite side of the church which will also have to be dealt with. Ok if we put down the plastic is this going ot send the roots onto other beds?  I can see this becoming a never ending story. Am I right?

I think roots will invade both eventually.  My trees seek all water sources.  If there IS water, there are tree roots.  Otherwise, I'd dig a sacrificial hole and give daily offerings of water to the tree. But I'm not a tree expert.  

Chris,
OK ... hmmm maybe, that idea about watering would work in conjunction with the other.  Thanks Chris.