Help me understand soil testing

I have an area in my backyard that I would like to turn into a garden, for a long story made short, I decided I should test the soil for a baseline as I build up fertility.  The soil is super rocky and very compacted.  I got the soil test back from the university and it’s a resounding everything is awesome l, we recommend nothing.  A lot of people have suggested to me to not add compost because it will make too much nutrients.

My soil is untouched never fertilized or compost added for at least 50 years.  It looks like rocky death to me.  Can compost really hurt my soil?  

I reckon since the fertility is there, I need to work on structure.  I planned on several different things, in one area I was going to try daikon radishes to break up the soil and let them rot in the ground.

In another area I thought about opening the soil up with a box blade

I had intended to add compost, worm castings and tea and biochar, but now I’m hearing that I need to not put compost near my soil because it will be over amended and the the only thing I should do is nitrogen

Thoughts on how to get structure to my soil?  I added a picture where I dug out a post hole so you can see the soil I’m talking about

I'm only basing this opinion on what I can see and your soil test.  I used to have very similar soil on a farm I owned years ago.  How do you feel about sifting rocks out of your soil?  You won't regret "de-rocking".  It's important.  I used to have a huge farm and we used a "rock picker" on it to great effect.  It was actually a large piece of machinery, pulled by a tractor that sifted rocks out of the soil, sent them to a conveyor belt and left them in rows to be collected and moved out of the farm soil.  I mention this to emphasize how important it is to remove rocks to improve your results.  I'm just tossing out relevant experience to give you a hand.  You'll dread those rocks over time if you don't get rid of them.  The work is hard, slow, and will make you question your wisdom in deciding to grow a garden.  But if you want a garden...

Best of luck with whatever your decide.

al aric wrote:I'm only basing this opinion on what I can see and your soil test.  I used to have very similar soil on a farm I owned years ago.  How do you feel about sifting rocks out of your soil?  You won't regret "de-rocking".  It's important.  I used to have a huge farm and we used a "rock picker" on it to great effect.  It was actually a large piece of machinery, pulled by a tractor that sifted rocks out of the soil, sent them to a conveyor belt and left them in rows to be collected and moved out of the farm soil.  I mention this to emphasize how important it is to remove rocks to improve your results.  I'm just tossing out relevant experience to give you a hand.  You'll dread those rocks over time if you don't get rid of them.  The work is hard, slow, and will make you question your wisdom in deciding to grow a garden.  But if you want a garden...

Best of luck with whatever your decide.

I agree and also have mixed feelings.  I did some chicken tractoring this year and grew a large amount of corn sunflowers and squash.  I did this by just making a sharp stick and poking a hole big enough for a seed to drop in to.

I can’t help but wonder if I was able to build loamy soil with rocks it might not really matter if I never disturb the soil much when I plant.  Obviously I’m not hilling up any potatoes in my ground.

Hi Eric, Thank you for sharing your test results.
I can see what you mean about being surprised by the results, your soil does look pretty rocky, although rocks can be useful too (see this thread for a discussion of whether to leave or not). I note they didn't do a soil texture test (sand:silt:clay) which will give an indication of how freely draining/moisture retentive the base soil is. I can't assume it is free draining because of the rocks - the rest may be clay. It does seem to have a reasonable amount of carbon, which will help with the soil texture and water retention of course. I think the trouble with the nutrient tests for soils is that modern agriculture is more like hydroponics than gardening.....no mention of soil life in the soil food web that moves and transforms the nutrients for the plants.
Since you have plenty of nutrients, and we are still fairly early in the autumn, you may be able to get in a 'green manure' crop to transform those nutrients into plant material to return to the soil. Maybe something like daikon radishes that will send down taproots to break up the compacted soil, or buckwheat or annual ryegrass may be another option.
I don't think finished compost ever has too many nutrients? Adding manure or high Nitrogen materials is obviously unneccessary, but bulky materials that improve soil texture will still be useful. If you have access to fallen leaves that would be one good amendment, but growing a bulky crop in situ is probably least work.

Hello fellow rock farmer!

I live in the New England area where my property has more rocks than crops. If I dig in certain areas, I might be lucky to hit some true soil but most of the time I'm fighting gravel, pea stone, baseball and cantaloupe sized rocks. It seems when my partner finds a spot she wants to plant something, it is always on a watermelon sized stone.

I have utilized two options at my disposal due to this phenomonen.

General Annual Garden - Raised beds are the bees knees. There is cost associated with this (The bed material itself, the fill, tools/infrastructure that work with a raised bed) but most of it us upfront. I purchased rough cut 2 inch thick by 12 inches wide board and made beds out of that. 12 inches deep has been plenty for the crops that I grow including root crops.

I wasn't as knowledgeable about soil components when I started and I used a mixture of 50% expanded coir and 50% fresh steer manure compost. I did not have a lot of luck but with a years time to mellow the compost, some covercrops, and other amendments I'm finding quite a bit of success.

Perennial Garden - This has been a delight for me. The key is to find the spot where you want or have your perennial garden and mulch the ever living hell bad place out of it. I have put about a foot of pine arborist chips down and wait for a good soaking of rain. When the chips have settled down a few inches, rake it back and start digging. You will be AMAZED how easy the shovel goes in as long as you don't hit a rock. If you do hit a rock, dig it out. You are shooting for about 2x the root ball of what your planting.

I have made a sieve that fits across my wheelbarrow out of a single 2x4x8 pressure treated board, I made a rectangle and I used a scrap piece of 1/2 hardware cloth that I bent around the rectangle frame. I attached it to the frame using galvanized pipe strapping and a bunch of short nails I had on hand. 1/2 to 4 inch rocks get added along the roof drip line to break up water as it hits the ground and take the impact of snow loads falling off. Larger rocks get added to my stone wall that delineates the mulched garden space from my lawn.

Its work, but make it work for you!

The testing is helpful, but I would go further.  Healthy soil has been doing something similar to what nature would do, with all of the life along with it.  In Missouri, I would think that the area would have trees and bushes in it.  Get life into your soil.  I agree that mulch would help.  Naturally, leaves would fall in autumn. Branches would fall, and fungi would grow on that.  Deer and other large mammals would relieve themselves on it.  You can do your part in that area.  

Does your soil drain well? Use that hole or dig another and fill it with water. See how quickly it drains.  Is there organic material in your soil? If not, it's not healthy soil.  The microbiology in your soil moves nutrients and creates active life.  

John S
PDX OR