As January ends, it's a swell time to test the pH, nitrogen, potash in soil
Welcome to Horsefeathers Farm on this, the last day of January.
Three cheers for El Niño, the warm ocean phenomenon that’s steering the winter storms to the south and north of the Pacific Northwest, leaving us for the most part unseasonably warm and dry.
Gardeners throughout the region are getting itchy fingers, watching the buds swell on ornamental shrubs and flowers. The Indian plum trees along the fringes of my forest look like their buds could burst out any day now. The cluster of primrose plants in a flower bed leading to the front pasture is turning bright green, stunted somewhat by its shady position but poised for an early floral show nevertheless.
Today, I’ll finish pruning all the fruit trees and blueberry bushes. Already, my earliest-producing Asian pear tree looks like it’s in mid-February form.
Don’t get me wrong. I’ve been down this mild-winter road enough times to know that another cold spell or two could be just around the bend. The only things growing in the garden are the garlic planted in November and the chives, a perennial plant. I have no idea yet whether the dahlia tubers I left buried in the ground and topped with several inches of compost survived the December cold snap.
But this El Niño weather pattern seems to be firmly entrenched, leading me to believe that the last deep freeze is behind us.
With the pruning all but done, I started getting eager last week to play around in the garden. So I took the advice of longtime WSU extension agent Don Tapio and bought a simple soil test kit to check the fertility of my garden soil.
Late January and early February is a good time for a soil test, Tapio noted. It takes some of the guesswork out of how much and what fertilizers to use in preparation for the growing season. Just as important, it can save a backyard gardener time and money by avoiding purchase and application of fertilizers the garden doesn’t need.
The $7 it cost for a kit to test for pH, nitrogen, phosphorus and potash seemed like a good investment, especially given that I’ve never tested my soil after seven years of gardening at Horsefeathers Farm.
Before heading to the office Thursday morning, I grabbed eight soil samples about 4 inches beneath the surface in various locations of my leaf-covered, sleeping garden. I mixed them in a container and took the soil to work, along with the test kit, which consisted of four color-coded plastic tubes with capsules of powder to use in the four tests.
Aided by the steady hand of Nick Harrison, a 14-year-old NOVA School student who job-shadowed me two afternoons last week, I mixed some soil and water together in the plastic tubes, added the powders, shook the tubes well, then waited a few minutes for the colors to develop in each tube.
The results showed that my soil pH is just about neutral, maybe a touch alkaline. Because most of the vegetables I grow favor a neutral to slightly acidic soil, I might try to bring the pH down a bit with a sulfate product.
The nitrogen reading came in somewhere between very low and low. I won’t have any trouble boosting the nitrogen level before planting, thanks to a large mound of horse manure compost that has been cooking in a covered pile for more than a year. Nitrogen is responsible for leaf growth and green leaves.
The phosphorous registered somewhere between medium and high. It’s essential for good root, fruit and seed development and aids the plant’s resistance to disease. Looks like I’m in good shape there.
The potash levels in the soil appear to be quite low. Potash boosts a plant’s early growth and stem strength and improves the color and flavor of fruit. I have noticed some of my crops getting off to slow starts in past springs. Maybe it has more to do with cool weather and lack of sunlight, but maybe an extra shot of potash would help.
I shared the results of my soil testing with Tapio the other day. He told me not to stress out too much.
“Most gardeners worry way too much about their soil composition,” he said. “If someone has a garden that’s productive year after year, they’re probably already doing most of the right things.”
Put another way, getting the right mix of pH, nitrogen, phosphorous and potash is important, but so is favorable weather, the right watering regimen and strategies to control garden pests and diseases.
That reminds me: Another year has slipped by without me putting up a fence around my garden to keep out the pets and wild animals.
John Dodge: 360-754-5444
jdodge@theolympian.com
This story was originally published January 31, 2010 at 12:00 AM with the headline "As January ends, it's a swell time to test the pH, nitrogen, potash in soil."