UMass chemist Tracy Allen and her staff analyze soil from all over the U.S.

Sometimes a gardener needs a chemist.

This is where Tracy Allen comes in. Thousands of tiny plastic bags filled with dirt are shipped to her office at the Soil and Plant Nutrient Testing Lab at the University of Massachusetts, Amherst, every year.

Allen, two scientists, a lab technician and student interns work to analyze soil samples from all over the country to help farmers, gardeners, and anyone else who is looking to improve their green thumbs. “Pretty much anybody who has concerns about their soil sends us little bags of dirt,” she says.

These samples tell a story about the plant’s environment and, for $15, and in about two weeks time, the lab’s staff generates a customized report which includes the soil’s nutrient and mineral content and its pH, or acidity level.

The test results typically come in a two-page document that lists the values of chemicals like potassium and phosphorus and sulfur. It also screens the soil for heavy metals like lead that could contaminate crops and provides customized recommendations.

There might be recommendations for fertilizer or limestone calculations for each plot of land. This can involve math, which can be intimidating to some home gardeners, says Allen, so she often gets calls with questions, which she happily takes. “Part of the deal is  that if they need help they can call and email the lab and we can walk them through it,” she says. “People think it is more complicated then it is and when I explain it to them they are happy.”

The report might reveal, for example, that a lawn doesn’t have enough potassium in the soil, a nutrient that facilitates photosynthesis. Another problem could be too much salt, which can burn roots. Some heavy metals, like aluminum, might be detected, which can stop a plant from absorbing nutrients, leaving gardeners wondering why their plants’ leaves are brown.

Each plant has its own specific needs, Allen says, such as an ideal soil pH. Blueberries and azalea plants, for example, thrive in a more acidic soil while vegetables like carrots and spinach typically need a more neutral or slightly acidic environment.

Since every landscape has its own makeup, there is never a one-size-fits-all solution to any gardening problem, she says. A delicate balance of nutrients, texture and acidity in the soil can be the difference between a thriving roots system and decay.

“The soil is basically an environment for the roots and if the environment isn’t correct then the plant can’t thrive,” Allen says.

While almost half of the lab’s clients are backyard gardeners, testing requests also come in from commercial enterprises like golf courses and landscaping companies.

 Holyoke Community College in Holyoke uses the lab to help it keep the campus grass green.

“A lot of times you can see the results right away,” says Alice Brainard, who works the grounds at HCC.

When she started the job 20 years ago, the soccer field was mostly bare and the graduation field was suffering. A test from the UMass lab found that the soil was low in potassium and calcium. Within a year, the grass was green again.

The test results are like a map, Brainard says, suggesting limestone and fertilizer. “You are not running blind, this way you have something to go by, you are not guessing.”

Years ago there were labs like this one in every state, Allen says, but state and federal funding dried up, forcing many of them to close. The UMass lab was able to scoop up some of their clients, mostly by way of referrals and word-of-mouth, she says. 

Despite spending her days surrounded by dirt, Allen, who runs the lab, wears a pristine, white lab coat. One corner of the room is filled with little boxes of soil. The recently arrived samples live under the laboratory’s florescent lights until they are passed through a device called a spectroscopy that uses a torch to burn off moisture from the soil. The burning mist emits light, some not visible to the human eye, that is used to measure the soil’s elements. But just by looking at the samples, Allen can tell a lot. The dirt from Ohio is light, dry and crumbly. New England soil tends to be a bit sandy.

“This one is from the Midwest,” she says, gesturing to a dark brown sample. “Their soil is finer, there is more clay in it.” It’s soil that is generally rich in nutrients with an alkaline pH. “That’s why it’s been historically where they grow lots of wheat and corn.” 

One sample comes from a vegetable gardener wondering why the tomato plants growing in it aren’t delivering. Another batch is from a watermelon patch where the melons aren’t thriving. Watermelons like slightly acidic soil, Allen says, so the pH might be off.

Throughout the years samples have come in from vineyards as far away as California and from cranberry bogs on Cape Cod, Allen says.

“We’ve got customers from all over the place, different occupations and reasons for testing,” she says.

The lab tests soil year round, but during peak seasons — spring and summer — up to 300 samples can arrive in a day. Many come from home gardeners here in western Massachusetts, an area with a unique geologic history that often causes crops to struggle, Allen says. “New England soils are sandy and acidic and generally nutrient-poor and that is because 10,000 to 12,000, years ago, this area was covered in glaciers,” she says. When the glaciers retreated, they left a jumbled mixture of soil and rock. These large soil particles have not had the time to break down into layers of silt or clay as they have in the Midwest, for instance. This makes it more difficult to grow crops. 

As a result, gardeners here tend to go overboard in doctoring their vegetable plots, which also can make for unhappy plants, Allen says. “People tend to over do it because they don’t understand that there is such a thing as too much compost,” she says. The recommendation for these folks is just to wait it out. Time and the rain will eventually fix the problem. 

Tomato plants, which can be fussy, are a common concern. “People love their tomatoes and they are very sad when it doesn’t work out,” she says.

Tomatoes like soil that is slightly acidic. The plants and their produce will suffer if they are subjected to inconsistent watering. And, damage from a prolonged hot spell may be irreversible.

If the plants leaves are showing signs that a fungus has attacked, Allen and her staff will refer the case to another lab on-campus, the Plant Diagnostic Lab, that can help pinpoint the problem. 

Allen also gets frequent inquiries about pumpkin plants.

“We have a bunch of pumpkin growers that all want to grow the biggest pumpkin ever,” she says. She doesn’t have a secret for producing massive orbs, but just like any other plant, she says, pumpkin plants need to live in healthy soil with a balanced pH, rich in nutrients — but not too many.

Allen says she doesn’t have a garden, but does have a deep love and respect for dirt. Before she came to discover the complexity of soil, she says, she had spent years working as a secretary. In her 40s, and tired of the grind of a low-paying, high-stress job, she decided to pursue her interest in nature and go back to school through the UMass Amherst University Without Walls, a program for non-traditional students.

She started studying wetlands, but her adviser convinced her to take a soil science course. She did and was hooked. She started working in the soil lab where she has been ever since.

“It’s not just dirt,” Allen says, “People don’t realize what’s beneath their feet. It's something that seems so simple, but it is so complicated and I just find the interaction between all these elements fascinating.”

Lisa Spear can be reached at Lspear@gazettenet.com.

How to connect

For a list of services and ordering information, visit the lab’s website.

Editor’s Note: This story was changed at 10:55 a.m. on Dec. 15, 2017, to correct the link to the lab’s website.