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Joined: Sat Aug 30, 2014 6:29 pm
Location: Iowa, USA zone 5

Please help with soil test results



I'm still new to this. Any recommendations on what I need to add. It will be a total of around 1,225 sq ft with amaranth, quinoa, corn, potatoes, tomatoes, peppers, onions, cucumbers, carrots, and more...I'm sure I'm forgetting stuff too. I'm also going to put in a winter compost crop of rye, wheat, hairy thatch, and fava beans.
Thanks for looking, can't wait to hear some input!

Posts: 11360
Joined: Tue Jan 01, 2013 1:32 pm
Location: hawaii, zone 12a 587 ft elev.

Re: Please help with soil results

This is the organic forum. If you want organic recommendations you can ask for that when you submit your test otherwise, they will always answer with synthetic fertilizers.

Your soil test is actually pretty good in the phos and K ranges. You are in the middle. You would need to add some nitrogen. The total nitrogen is usually divided. Part of the nitrogen will be given when planting with side dressings in 3- 4 weeks. Since you are planting legumes that will help put some of the nitrogen in the soil but it will not become available until the next crop cycle. If you get good nitrogen fixing nodules you are very lucky. If not inoculating the seeds will improve nitrogen fixation. Nitrogen fixers work faster in warmer weather and are slowed by the cold. Hairy vetch and cowpea use different inoculants. I don't know what Hairy thatch is, I have not heard of that. Winter rye and buckwheat are good for adding biomass but would not be fixing a whole lot of nitrogen.

Do not add chicken manure. Your pH 7.7 is already on the alkaline end of things. Chicken manure might edge that up a half point and you really would not want anything over 8. Adding compost will buffer the pH.

The soil test recommended adding elements in single form. It really is not that easy to do organically. There is always going to be some other elements in there. Organic fertilizers will vary in NPK depending on the source, time of year and environment. Nitrogen in organic fertilizers need to be converted by the bacteria in the soil so are released slowly over time. Plants usually need more nitrogen a couple of weeks after planting. There will be enough stored energy in the seeds to get the plants off to a good start but young plants need the nitrogen available when they are actively growing.

The corn will probably be your heaviest nitrogen feeder so the corn should follow a legume (inoculate if you have to increase nitrogen fixation) to benefit from the cover crop. Remember cover crops should be tilled in at flowering. If you are eating the beans, you are taking it away from the soil.

You can actually call the extension office and ask them for organic recommendations based on your soil test.

For myself, I do not like a pH that high. I would add a little sulfur or peat moss, especially for the corn carrots, peppers and potatoes. If I were planting cabbages I would not worry about it. If you were planting blueberries they probably would not be happy. Most plants like to be slightly acidic.

deal Soil pH for Vegetables

Vegetable Garden Soil pH Range
Artichokes 6.5 to 7.5
Asparagus 6.0 to 6.5
Beans, Bush 6.0 to 7.5
Beans, Green 6.0 to 7.5
Beans, Lima 6.5 to 7.5
Beans, Pole 6.0 to 6.8
Beets 6.0 to 7.5
Broccoli 6.0 to 7.5
Brussels Sprouts 6.0 to 6.8
Butternut Squash 5.5 to 7.5
Cabbage 6.0 to 7.5
Carrots 5.5 to 7.0
Cauliflower 6.5 to 7.0
Celery 5.9 to 6.9
Corn 5.5 to 7.0
Cucumbers 5.5 to 7.5
Eggplant 5.5 to 7.0
Garlic 5.5 to 7.5
Horseradish 5.5 to 6.8
Lettuce 6.0 to 7.0
Okra 6.0 to 8.0
Onions 6.0 to 7.0
Peanuts 5.5 to 7.0
Peas 6.0 to 7.5
Peppers, Bell 5.5 to 7.0
Peppers, Hot 5.5 to 7.0
Potatoes 4.5 to 6.0
Pumpkins 5.5 to 7.0
Pumpkins, Giant 5.5 to 7.5
Radishes 6.0 to 7.0
Rhubarb 5.5 to 6.8
Shallots 6.0 to 7.0
Soybeans 6.0 to 6.8
Spinach 6.0 to 7.0
Squash, Summer 6.0 to 7.5
Squash, Winter 5.5 to 7.5
Strawberry Plants 5 to 7, but optimum is 6.0 to 6.8
Sweet Corn 5.5 to 7.0
Sweet Potatoes 5.6 to 6.5
Swiss Chard 6.0 to 7.5
Tomato Plants 5.5 to 7.5
Watermelon 5.5 to 7.0
Zucchini 6.0 to 7.5
- See more at: ... 6xAY2.dpuf
Happy gardening in Hawaii. Gardens are where people grow.

Newly Registered
Posts: 3
Joined: Sat Aug 30, 2014 6:29 pm
Location: Iowa, USA zone 5

Re: Please help with soil test results

Wow, what a great reply!! Thank you Imafan!

I definitely want to go all organic, that is why I posted in this forum.

I'm confused about the nitrogen, I didn't see anything about how much is in my soil, so how do I know how much to add? Don't know if it will make a difference but right now the yard is about 90 percent clover.
I'm also not sure what "side dressings" are could you explain that for me?
Yes I meant hairy vetch... not thatch lol, not sure were that came from. Would you recommend a different cover crop or is the legume/ biomass mixture OK? Also, I was planning on cutting the cover crop for compost instead of tilling it in. I'm trying to stay away from tilling as much as possible. I will be double digging by hand.

I'm definitely going to call my extension office and see what they recommend.

Yes the pH is a little scary lol...I already have a couple bails of peat laying around, the question is how much do I use?

I'm sure I'm missing sum thing, but it is rather difficult to write replys on my phone as I do not have internet on my computer.

Thank you very much!
Please bear with my ignorance ;) lol

Posts: 11360
Joined: Tue Jan 01, 2013 1:32 pm
Location: hawaii, zone 12a 587 ft elev.

Re: Please help with soil test results

Nitrogen is a volatile element so is rarely reported on soil tests unless you ask for it and it would be changing all of the time. That is why even if your soil were in the extreme ranges there would always be some nitrogen recommended. Your soil test recommended 4 lbs of elemental nitrogen for 1000 sq ft. Since you are using legumes and clover they will add nitrogen if tilled in at the proper time. Organic sources will vary in the amount of nitrogen they have. If you are going to use it in the compost and put it back in the garden later you will get some of it back, but some will also be lost in the composting process as the bacteria and fungi making the compost will be using some of it and some of it will be lost through denitrification back into the air. The next legume you plant that has nitrogen fixers will again reclaim some of that nitrogen and bring it back to the soil.

Usually natural systems are in balance, then people get in the way. They concentrate the planting of crops; add outside sources of nutrients to support them all in a relatively small environment. Then they take some of the nutrients out because it is harvested for food. If the crops are tilled in the system would get most of the nutrients back except what the humans took out and what was lost through natural processes. If the crops are taken away and composted instead, the soil does not get back those nutrients unless the compost is added back later. The real trick is to figure out how much the system leaks and only replace what is needed to restore balance.

How leguminous cover crops work is that the nitrogen fixing bacteria attach themselves to the plant roots when they are very young, pretty much infecting them. They don't move well through the soil so that is why inoculants need to be applied on or very close to the seed. The nitrogen fixing bacteria convert nitrogen from the air and use it to keep themselves alive and some of it gets to the plant as well. The real return on investment is that while the nitrogen is locked up in the plant and the bodies of the bacteria, it is very stable. Once the crop is tilled in and the plants and bacteria die and decompose, they slowly release the nitrogen in their tissues back to the soil. Slow release nitrogen feeds the soil and plants over a longer period of time. Fast release nitrogen is usually given in divided doses because any excess amount that cannot be absorbed by the plants and microbes in the soil will be converted by other bacteria back into elemental gaseous nitrogen and released back into the air.

Mother nature is no wastrel, she recycles everything but there has to be a balance between what goes in and out of the system. Troubling is that excess nitrogen, like excess phosphorus may lead to the release of more greenhouse gases and pollution of waterways by the leaching of fertilizer that will cause algae blooms. This is a problem usually blamed on commercial fertilizers because they are so concentrated, but organic fertilizers especially manures from farms where animals are concentrated can add so much extra nutrients that runoff can cause the same problems.

This is a good article on the nitrogen cycle with links to nitrogen fixation in the soil ... Cycle.html
Happy gardening in Hawaii. Gardens are where people grow.

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