Soil Testing

CSU Soil Kit

For the longest time, I was convinced that not having an automatic sprinkler was the main reason I killed plants.  After many years of watching plants shrivel and die I got a new system and ‘oila’ I had plants that thrived like my neighbors.

Well no that’s not true.  Many of the plants that needed a good dose on a regular basis did perk up.  But I still have trouble spots.  Take for example the shade bed under the Catalpa tree.  Although I’ve top dressed each year with Eco Compost and now have a regular watering schedule, my hostas still died.  They didn’t wilt like it was a watering issue.  But over a 3-4 year period, each year they got smaller, and would not produce the same number of leaves as they had the year before.  I thought it was a slug problem but I’d also planted the following plants only to have them die in a couple year’s time.

Fern, lily of the valley, hen’s and chick’s, columbine.  My solution has always been to add more compost and a good dose of mulch… but nothing has seemed to work.

My friend Martha Kirk, owner of Signature Gardens,  suggested I get my soil tested.  She is a master gardener who has studied in Colorado institutions like the Denver Botanic Gardens and Colorado State University.  At a recent CSU session, she learned much about soils and their needs and how harmful some of the products, sold as fertilizers today, can be to the microbiotics that make nutrients available to plants.

CSU Soil Kit

Martha said that CSU has done chemical analysis on soil amendments like fertilizers, bagged compost, and manure.  Many of the admendments had inconsistent nutrient values.  Take a fertilizer that is labelled 10-10-5 (Nitrogen- Phosphorus- Potassium).  You would expect by volume 10 percent available nitrogen, 10 percent available phosphorus and 5 percent available potassium (potash). The remaining ingredients would be inert or inactive ingredients.  Most often CSU found that those percentages varied by batch, so you are never guaranteed the percentages the packages say. Using fertilizers rich in potassium can add salt to your soil.

Manure can be a dangerous amendment bought out of the bag.  In Colorado so much of the manure that ends up in bags comes from feed lots whose components can be harmful to plants.  The main issue is copper.  Cows hooves are sprayed with a copper-based solvent to prevent rot.  This copper can leach into the manure.  Also grain fed cows can produce manure with a higher salt content that is concentrated when you compost manure as recommended.

Salt is hard to remove from soil in Colorado due to our semi-arid climate and clay rich soils.  So its especially important to avoid practices that add salt to your garden’s soil.

The death toll in my garden by dollar amount is probably in the thousands by now, and that is being conservative.  So a $28 soil evaluation is a drop in my gardening bucket.

If you too are flummoxed by plants whose hardiness factor is supposed to be 10 but you still can’t grow it, maybe its time for a soil test.

To test your soil:

First go to the Colorado State University Soil Labs site

Click on Locations to Pick Up Soil Kits.

I picked mine up at Creek Side Gardens

There are two main areas of issue in my yard so I decided to do 2 soil tests, one for my ailing shade garden, and the other for my vege garden.

I dug down 6 inches with a trowel, making sure to collect soil from the top to the bottom of that 6″ column. I did this in 5 different areas of the gardens.  Then I mixed the samples in a plastic grocery bag and left them out to dry over night.  I will send the samples to the site labelled on the US Post Delivery box that comes with the sample kit I received from Creek Side Gardens.

Results will be published soon.

For more information on soil admendments

An amateur gardener who loves to watch the garden grow.