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Help interpreting soil test results, veggie garden recommendation #873086

Asked June 14, 2024, 10:47 AM EDT

Hi~ I just got my soil test results back for a volunteer veggie garden that I manage at work. We have about 8 raised beds that got new soil this spring from a landscaping company that my work uses. The soil looked fairly rocky (photos attached), so I took samples from four of the beds and sent it in right away for testing. See attached. So far the beds seem to be growing pretty slowly - they were planted with seedlings about 3 weeks ago (around 5/21). Something definitely seems off! Any advice on what the soil might need for amendments besides the N-P-K recommendations? Thank you so much! Martha

Hennepin County Minnesota

Expert Response

Hey folks - follow up question! Doing a little digging, since the pH appears to be high, thoughts on trying to lower the soil pH?  How would I go about doing that?

The Question Asker Replied June 18, 2024, 12:51 PM EDT

Oops! Sorry for the follow up, specifically, I meant should I try an ammonium sulfate fertilizer since I need N anyway, and it would help to lower the pH? Or is there a better method?

The Question Asker Replied June 18, 2024, 1:08 PM EDT

It appears that the soil you received from the landscape company is not intended for raised beds. If you paid for it, I would contact them with your concerns and ask them to amend it. 

That said, it looks like compacted soil that was removed from another landscape job. If you choose to keep it, you should first add some good compost to it and work it in to the top 6 inches. Since you have already planted seedlings, you can top dress them now and add more compost in the fall.  Your test says that it has very little organic matter in it and this will help. You could also add some well composted manure in the fall. If it is not well composted, you will get a lot of weed seeds. Then add more compost again next year. 

Loosening up the soil with organic matter will go a long way to making your raised beds produce well. 

Then, follow the recommendations on the soil test report. Use a fertilizer with only nitrogen in it. (10-0-0). 

It is difficult to alter the PH in soil. It’s also difficult to lower the potassium but over time, these should level out. 

Deb Reierson Replied June 18, 2024, 5:20 PM EDT

Ok, thank you! I’ll definitely add compost. Luckily we’ve a pile of it still from the Plate to Garden program (MN Composting Council).

 

Given the pH being high and the fact that plants can’t take up Nitrogen as well due to that, could I over-fertilize with a Nitrogen only fertilizer to try and compensate for that? Or is that asking for trouble?  The slow growth of these beds has been really frustrating for our volunteer gardeners so I really want to try something to get better yields this season if possible.

 

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The Question Asker Replied June 18, 2024, 5:38 PM EDT

It’s never a good idea to over-fertilize. But you can add some now, and again in 3 weeks. In addition, you could use a time-release fertilizer such as Osmocote for vegetables. 

Deb Reierson Replied June 18, 2024, 8:03 PM EDT

You could add some elemental sulphur but don’t do that until this fall when all of the plants are done and pulled. You can find it at most nurseries. Follow the package instructions. 

Right now, the best you could do would be to dig in some of the compost while the plants are still small. Do this in-between the plants but don’t disturb them. 

FYI - my last soil test read about 7.8 and my vegetables are doing great!

Deb Reierson Replied June 18, 2024, 10:32 PM EDT

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