Wednesday, April 11, 2012

Soil Testing -- Easy and Worthwhile

Primrose, barren strawberry, grape hyacinth, heuchera, and lamium.
I don't have my soil tested every year, but following last year's above-average rainfall, I wondered how many nutrients were washed away, and decided it was worth the effort this spring. As well as nutrient deficiencies, a soil test can tell you the soil's acidity (pH) which is important because if the pH level isn't in the correct range, plants cannot take up nutrients.

I purchased three soil testing kits from our local Extension office to test the soil in the shade garden, the cottage garden and the vegetable garden. These areas are devoted to different types of plants (flowers and vegetables), or are composed differently (lasagna garden and tilled garden), so require separate samplings. Each kit comes with easy-to-follow instructions and diagrams showing the spacing of the samples. I began in the shade garden.

The shade garden
 Using a trowel and a clean pail I obtained thin slices of soil from at least 13 places in the shade garden.  I collected soil to a depth of 6 inches, the approximate depth of each plant's feeder roots, first removing debris from the surface. I mixed the samples together in the bucket.

The next step was to spread the soil on newspaper in a warm room to air dry overnight. Only an obsessive gardener would use the dining-room table. (I did place a thick plastic tablecloth under the newspaper.)

The next day, I took a 1 cup representative sample and placed the soil in the mailing kit bag. I filled in the form that was provided and placed it in the mailing envelope and sent the packet to the laboratory at PennState University.

I took samples from the cottage garden and vegetable garden in the same way.

The cottage garden is waking up.
Creeping phlox and red peony shoots next to the first shasta daisy leaves.
The kitchen garden -- one bed planted with cool-weather crops.
 I received the results in less than a week. The soil test report for the shade garden shows that phosphate, magnesium and calcium are above optimum. Potash is below optimum! The recommendation is to apply 10-10-10 fertilizer -- 1.5 1bs per 100 square feet.  The numbers on the fertilizer (10-10-10) refer to Nitrogen-Phosphorus-Potash in that order. (There is no reliable test for nitrogen.)

The pH scale measures how acidic or basic a substance is. The pH scale ranges from 0 to 14. A pH of 7 is neutral, a pH less than 7 is acidic and a pH greater than 7 is basic. My shade garden has a pH of 7.2. Most of the shade plants prefer a more acidic soil, so I need to add sulfur. The report includes recommendations for the amount of sulfur needed per 100 sq ft.

My favorite 'double' daffodils.

Every year I apply liberal amounts of organic matter to all my gardens, and an interesting result of the testing shows all my beds have a CEC (Cation Exchange Capacity) of 17+. This means, in simple terms, that I don't need to add compost this spring. The report recommends adding 1 inch of organic matter if your soil is less than 15.0 CEC.

How sweet the violets.
There were slight differences in the results of the vegetable garden soil and the cottage garden soil. I am so glad I got the tests, as I now have a plan to grow better gardens. I highly recommend you make the effort -- it is definitely worth it!

On another note, we have a mess to clear up due to the instillation of a new septic tank (one of the joys of living in a rural area where we need our own sewage system). We need to replace a lawn, repair a flower bed and reinstall the stone garden which houses my container garden!

What a mess!!

Happy Gardening!
Pamela x

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Jo said...

I've never tested my soil, but I know you can buy do it yourself kits so I may give it a go. It sounds like a big job installing a new septic tank. I hope it doesn't take you too long to get the garden back to ship shape.

spurge said...

Thanks for the info on soil testing! I've never had mine tested officially, as it always seemed like a lot of work and hassle. I can see that it's actually quite easy. I envy your organic matter content - not sure what mine is but certainly not 17!

Patsi said...

Good for you...soil testing is easy and worth while.Now the septic tank is another story...good luck.

Bridget said...

Good info on the soil testing. I certainly would'nt use artificial fertiliser though if you've been using just your own compost up to now. Organic liquid feed made from Comfrey and Nettles can give your crops the required potash. Wood ash also contains small amounts of potash.

Christine @ The Gardening Blog said...

Very interesting, I don't think we have such a service here in South Africa but I think I will keep a look out to see if they have home testing kits here. I think this is very valuable info.

Donna@Gardens Eye View said...

Great advice Pam...will have to check it out...sorry to hear about the mess...not fun cleaning it up.

Marguerite said...

A lot of work to get those samples but the amount of information you got in the test results seems well worth it. Yikes a new septic tank, that can't be cheap or easy to deal with. Best of luck to you there.

HolleyGarden said...

I've never had a soil test done. I'm impressed with how much information you got! Your soil looks beautiful. I hope the new septic tank installation goes smoothly.

Indie said...

I've done the do-it-yourself tests, but the mail in one seems more in-depth. It's nice that they give you advice on what to add! I really should mail some off some day to the place here in Raleigh.

The garden is looking like a lot is coming up! Very pretty!

Vesna - Kalipso said...

Hello Pam, I too have tested the soil in my garden. I bought the testing kits in the gardening shop. Pretty much neutral everywhere.
I am looking forward to the new gardening season in your garden.
xxx Vesna - Kalipso

Masha said...

I am glad you got the soil test done - it takes so much of the guesswork out of gardening! Here agriculture is big business and soil tests are expensive :(. I love your double daffodils too, very pretty!

Carolyn @ Carolyn's Shade Gardens said...

I am always advising my customers to test their soil but I haven't done my own in years. It's probably time. Am I correct that you and Julie will be coming next weekend? Have you invited anyone else?

Donna@GWGT said...

As a MG we do many soil tests at both the Extension office and on location. The testing involves the pH, soil texture and water holding capacity. The last two are observational with no chemicals. Many customers think the test includes mineral ID, but for that, the samples have to be sent to Cornell directly and the testing is very expensive. I would say 90% of the pH tests come back in the range of 7.0 to 7.4. It is rare to have our clay soil much more acidic. Also, the clay soil reverts regardless of how much sulfur is added so we usually suggest alternate plantings rather than fight the soil acidity. That or raised beds like you have you where you control what soil is added.

Wife, Mother, Gardener said...

Good for you for doing it! Soil testing is something that hangs over my head every year but I have not faced it to the finish yet. I know that it is folly, but we all have our funny limits in our own minds, yes?

Looks beautiful! I like the daffs with the Pulmonaria.

Pam's English Garden said...

I do agree with Bridget about adding artificial fertilizer which I have never done because I garden organically. Espome makes an organic 10-10-10, or I may mix my own using soybean meal, bone meal, and greensand.

Donna, As a master gardener I encourage home gardeners to test their soil. It costs less than $10 here and PennState does identify mineral content. I think it is good value. I agree with you totally about the pH. Actually, I will just be adding peatmoss as a compost to the areas needing a more acid soil. I do this most years.

Yes, Carolyn, we'll be seeing you next week. If any other garden bloggers would like to join as at Longwood Gardens and Carolyn's Shade Garden, you will be very welcome.

Pamela x

linniew said...

Oh Pam, you are so good to your garden! I know you will be rewarded. Sorry about the dang septic tank digging but at least it's a time of year when everything will heal up quickly.

Donna said...

$10 is a good value. It is $50 here for minerals and if it is more comprehensive, over $100. I have clients that have paid the scientists to come out to their properties, and that is really expensive. This is usually for trees hundreds of years old, like a beech at one client's estate that was really sick. Cornell's experts healed the tree with some experimental injections. Cooperative Extension is a great program. Thanks for your kind words on my post too.

Daisy said...

Looks like doing the test was worth it. I need to do the same, but I have too many beds with soil from different sources.

Alistair said...

Soil testing is always one of those things that I intend to do and never get around to it. I do know that it is on the acidic side as Rhododendrons do well.I often give the Rhododendrons a top dressing of ericaceous compost I expect this contains sulphur. I do like the set up of your kitchen garden.

The Redneck Rosarian said...

Thank you for this wonderful reminder of the importance of soil testing. We test our soil annually and strive for a 6.5 balance in our rose garden. It's easy today and a very lost cost.

michele said...

I like the idea of testing the soil. Something so simple yet many do not think of this.