We moved into our place in late December, 2008. In January we raced to get in vegetable beds. I used one of those home soil test kits to determine what we needed to do to the soil. According to the tests our soils were slightly acidic but completely deficient in all macro-nutrients. Ok, I’ll buy it, since it has been nothing but weeds for who knows how long (the house was empty almost 2 years prior to us moving in). So we amended the soil as recommended.
Now, we’re totally organic and by following the recommendations we should have been good. And our garden did start out fairly strong. But after not too long, plants started to fail. Our squash completely failed. So I did another soils test. Again it said the same things. So we amended again. This time we didn’t get any response from the plants. Maybe it’s the lack of heat this year? Then I noticed a light coating of white deposits on the soil along our drip irrigation lines. I knew this was bad. I then decided to send in soil samples to a professional lab.
It was bad. Salt. Saline Soil. We have salt water intrusion in our well. We’re the only well pulling off that aquifer. We thought we were good. But we are near the SF Bay. We are in a major drought. And the well could be too deep (salt water is heavier than fresh water and sometimes wells that are too deep end up bringing up the salt water instead of the fresh water).
But here’s the kicker, according to the lab we have an excessive amount of phosporus and potassium and plenty of nitrogen. The potassium is so excessive it is affecting the absorption of other nutrients. The lab also showed that our soil is alkaline. Hmmmm, but the soils kit said we were completely deficient in the macro nutrients and had acidic soil – twice! So I tried the home test kit one more time to see if maybe this had all changed since the last time I tested then amended. Nope, it read the exact same as it had all the previous times I had tested the soil.
Then I remembered that my mom has been having gardening problems even though she uses one of these tests every year and then amends appropriately. I now feel like I can’t trust these tests, which is a bummer because they are inexpensive. But at least with the lab tests they tell you the levels of macro and micro nutrients and give you specific recommendations.
10 thoughts on “Soil Testing”
What a bummer but great that you figured out the issue. It's interesting because you have such a spectaucular garden! I've never seen chard so huge!
We sent our soil to some university that did a full test for $11 or something like that. Totally affordable and worth it in my mind. Our big concern was lead from the highway nearby. We were good though!
Good luck to you!!!
That salt sure sucks the big one. But the fact is you guys were able to grow a hell of lot of food this summer, even though the weather was insane with late rainfall in the spring, temps too cold to sow outside, etc, for weeks. And then were the hordes of munching pests.
Are there salt-tolerant crops you could sow in the soil just to make lemonade with that pallet of lemons life has dumped? And then the more sensitive growers could go into (I hate suggesting this when your growing space is so big) raised beds?
Colorado State has a page on dealing with saline soils and apparently these can be managed to steer the salt away from root systems, but cripes that seems tedious. There's also double-row bedding systems where salt is tricked out of the planted row into a dummy dry furrow.
I am glad you posted about this, because I suspect we have something similar going on. Raised beds have helped a heck of a lot, but they are kind of a bitch to work with because of soil compaction and needing to continuously amend. And our back yard was truly a blank canvas, goodness.
Great info!! Thanks.
Love your blog, and what a great thing to offer consult. Wish I was nearby. : ) I am thinking Willamette Valley is a bit too far?
Who did your test? How did it differ from your home-test? Why do you doubt the accuracy of the lab test?
We sent our soil to U Mass, because I was very worried about lead in the soil. Our results were very useful. Too bad our soil structure is so lousy. I can't seem to reach the tipping point where my amendments make a difference in tilth.
Oh, I don't doubt the accuracy of the lab tests at all. It's the DIY home tests that I find inadequete and unreliable. They said we were deficient in every macro nutrient when in fact we were the exact opposite. They even got our pH wrong.
thanks for the reminder that i need to get on this. maybe i can figure out why my beets aren't growing.
sorry about the salt 🙁
I love your blog. Thanks for the soil test info.
I have heard certain varieties of plants can be used to concentrate a toxin in their leaves and stems. Then the plant can be disposed of. If you are still having the salinity problem, I can look for more info on which plants can be used this way.
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I also used a home soil test this spring (2011)which said I had low nitrogen and potash. I purchased more compost and also used what I made. I have harvested wonderful food from my garden.
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