Soil Sampling Essentials

by Andrea Laine, EMGV

Our master gardener office has fielded a lot of calls lately about soil sampling. And, we are a little more than six weeks away from the end of soil sample “free” season, so a refresher on how and why to prepare a soil sample seems appropriate.

Let’s begin with the end: November 28 is the last day soil samples will be accepted in the Durham  County Extension Master Gardeners office at 721 Foster Street, Durham. The Extension office is open Monday through Friday, 8:30 a.m. to 5 p.m.

Why bother with testing soil? It is the best way to set your garden up for success. The test results will tell you exactly what nutrients need to be added to the soil to grow what it is you desire in that spot.

Who tests the soil? The folks who analyze soil samples work for the N.C. Department of Agriculture & Consumer Services (NCDACS) in Raleigh. They are agronomists – soil scientists — and can also help you understand your soil sample report; Do not hesitate to call the telephone number on the report.

Master gardeners figure prominently during “free season” because one of us transports your collected samples to the right place in Raleigh for you. If you ask me, that’s even better than being free! Homeowners who sample soil between December 1 and March 31 must deliver the sample to the NCDACS themselves and the cost per sample is $4.

What will you need for this task and where can you get it? In addition to basic gardening equipment, you will need:

  • soil box
    soil sample box

    One soil sample box for each area of your yard that you wish to test. (See photo to left.) Do not assume that all the soil in your yard is the same. And know that it is perfectly acceptable to sample the soil in a raised bed.

  • A Soil Sample Information Form. One form has room for up to six areas.

So, that’s one form and multiple boxes. Soil boxes and forms are available from the Master Gardener office  and local garden centers (usually at the cash register). The boxes and forms are free.

How to obtain a good soil sample? Follow these five steps:

  1. Choose a day when the soil is relatively dry. Digging in wet soil is rarely a good idea.
  2. Prepare by cleaning and clearing; You want to begin with a clean stainless-steel shovel and a clean plastic bucket. Then clear away grass, twigs and leaves from the soil’s surface.
  3. Dig a V-shaped hole (strive for eight inches deep for a garden, four inches deep for a lawn).  Take a one-inch slice from one side of the hole and place it in the bucket. Do this at least six to eight times. To obtain one sample, you must dig several (or more) shovelfuls of soil from different spots within each area being sampled. This will ensure accurate results.
  4. Using a clean tool, mix the soil. Remove rocks and other large pieces of organic material. From this mixture, fill the soil sample box to the red line. Close the box. (If you have difficulty closing the box, don’t despair, try again. It will close eventually. Please do not tape the box.)
  5. Complete the Soil Sample Form. Two important points here: First, for each sample, you must choose a 5-character ID and place it on the sample box and on the sample form. That’s how you will know which results belong to what samples. I generally choose geographic descriptions like “fence,” “front,” or “woods” to distinguish the location from which I took the sample. But use whatever is meaningful to you. And it never hurts to write it down in your garden journal for future reference. Secondly, choose a “planting code” for each sample. This is a multiple choice question; choices are listed on the back of the form.

    soil codes
    One of these “planting codes” must accompany every soil sample.

Bring the sample(s) to the Master Gardener office within the Durham Cooperative Extension building at 721 Foster Street in downtown Durham before Nov 28. You will receive an email when the results are ready. The email will contain an online link to your report.

If you have questions at any stage of the process, feel free to contact the master gardener office by phone (919-560-0528), or by email (mastergardener@dconc.gov).

Resources
NDDA&Cs Agronomic Division, Soil Testing Section
www.ncagr.gov/agronomi

NC Cooperative Extension Services, Durham County Master Gardener Volunteer Program, Urban Horticulture Note No. 5: Submitting Samples for Soil Testing, October 23, 2007

Further Reading
A Gardeners’ Guide to Soil Testing
https://content.ces.ncsu.edu/a-gardeners-guide-to-soil-testing

Photo credits: Andrea Laine

Enjoying a Morning Cup of Coffee with My Houseplants

by Jane Malec, EMGV

A morning cup of coffee is a necessity at my house. It is just a part of getting the day started and I love everything about it — making it the night before, turning the pot on in the morning, and the aroma when it’s brewing. Over the years our coffee habits have changed due to the ever-fluctuating studies on the healthiness of, optimum consumption levels, or brew strength of a cup of coffee. It’s mostly decaf and fewer cups for us now.  Still, it remains a force of habit to pour the same level of water and ground coffee beans into the brewer regardless if we are running out the door or having a leisurely morning. Even if I reheat a cup later in the day, there is always a little left over brew sitting in the pot.

So I often walk around the house pouring the remaining cold coffee onto thirsty house plants. Our current home has a private well and I am ever more conscious of water usage. I make sure to pat myself on the back over my dedication to water conservation with every cup of coffee that soaks into the potting soil. I even wander outside to share the wealth with my container plants. A win-win, right? Or, maybe not. If there is a debate on human coffee consumption, I suddenly wondered if there might be one on plant consumption.

Coffee comes to us through a complicated path. To begin with, there are several species of coffee plants or trees, the two most commonly grown are Coffea arabica and Coffea canephora which is also called Coffea robusta. Arabica coffee is considered superior and commands a higher price than the robusta. Coffee production is a labor intensive process. The berries are picked by hand, sorted and allowed to ferment which removes a gelatinous tissue layer. Then they are washed with large amounts of fresh water. The seed of each berry, which is the bean, is roasted and then ground before becoming the beverage we enjoy. The degree of roasting the beans will determine the flavor, but not the caffeine level. Interestingly, the lighter roasts contain more caffeine so watch out you breakfast blend drinkers!

Which leads back to my curious question — is liquid coffee good for plants? There is a good amount of anecdotal information (on the Internet) concerning the use of brewed coffee for watering plants. However, there is little research-based information on this nor on liquid coffee’s benefits to soil.

However, there are some basic guidelines to help us understand if my “coffee watering practice” is helping or harming to plants. While coffee grounds tend to have a pH around 6.5 to 6.8 which is nearly neutral on the scale (neutral is 7), brewed liquid coffee is reported to have a pH level ranging from 5.2 to 6.9 depending on the type of coffee and how it is prepared. The lower the pH the higher the acidity; A drop in one full pH equals a factor of 10. For example, if the brewed coffee is 5.5 pH and the grounds are 6.5 pH, the brewed coffee is 10 times more acidic than the grounds.

Understanding that most plants like a slightly acidic to neutral pH and factoring in that most municipal water is slightly alkaline (pH greater than 7), it is possible that the acidity of the coffee could benefit plants. Also there are small measurable amounts of magnesium and potassium which are plant nutrients. Keep in mind that this information can only serve as a guideline as there can be other factors in play, for instance, if you have a private or community well, and whether or not you use a water softener.

The best recommendation is to follow some simple rules. Make sure the coffee is cold and then water it down. Never water with coffee if you add milk, cream or sugar. Know your plants pH happiness levels and then watch the impact this is having on your plants over time.  Adjust your morning coffee routine.   

Remember too much of a good thing is, well, too much of a good thing. Resign yourself to pouring some of the leftovers down the drain or on your compost pile. 

Maybe I could starting singing to my plants instead?  Hmm. 

Resources:

Coffee as Fertilizer?
https://web.extension.illinois.edu/dmp/palette/110109.html

Yard and Garden
https://extension.unl.edu/statewide/buffalo/Watering%20House%20Plants%20With%20Water%20%26%20Coffee%2C%20March%205%2C%202011.pdf

Clay soils
https://durham.ces.ncsu.edu/files/library/32/UNH%203.PDF

 

Fee-free Soil Testing Season is Here

Are you planning to have your soil tested this spring? After March 30, the peak season fee for soil testing will not be applied. That’s right–you can have your soil tested for free!

Do you need more reasons to bring those samples in for testing? Here’s a list, courtesy of the NC Department of Agriculture and Consumer Services:

SOIL TESTING

What is a Soil Test?
soil test is a process by which elements (phosphorus, potassium, calcium, magnesium, sodium, sulfur, manganese, copper and zinc) are chemically removed from the soil and measured for their “plant available” content within the sample. The quantity of available nutrients in the sample determines the amount of fertilizer that is recommended. A soil test also measures soil pH, humic matter and exchangeable acidity. These analyses indicate whether lime is needed and, if so, how much to apply.
Why Do You Need A Soil Test?
Encourages plant growth by providing the best lime and fertilizer recommendations.
When growers guess about the need for lime or fertilizers, too little or too much is likely to be applied. By using a soil test report, the grower does not need to guess.For Example: When applying too much lime, soil pH may rise above the needed level, which causes nutrients such as iron, manganese, boron, copper and zinc to become less available to plants.It is also common to see homeowners purchase one bag of lime when they purchase one bag of fertilizer. Based on an average lawn size of 5000 square feet, one bag of fertilizer may be enough. Applying one bag of lime over 5000 square feet, however, will have little effect on soil pH. Diagnoses whether there is too little or too much of a nutrient. 

Promotes environmental quality.
When gardeners apply only as much fertilizer as is necessary, nutrient runoff into surface or ground water is minimized and natural resources are conserved.Saves money that might otherwise be spent on unneeded lime and fertilizer.
For example, growers of flue-cured tobacco often routinely apply phosphorus. In areas where soil levels are high in phosphorus, a soil test could save these farmers up to $60 per acre.

Soil test kits are available at the Durham County Cooperative Extension Office, 721 Foster Street. It’s easy, it’s free from April through November, it may save you money on fertilizer, it’s good for the environment AND your plants.

-Ann Barnes

Consider Composting

by Andrea Laine, EMGV

A few years ago I decided to begin composting, again. I had tried twice before in different places I had lived. Neither of those first two attempts were successful. There must be something to the saying: ‘Third time’s a charm,’ because I have fallen in love with composting.

Composting is the act of creating compost in your own backyard. Compost is decayed organic matter that once fully broken down makes an outstanding soil amendment for all kinds of plants, shrubs and trees.

Briggs compost
A three-bin unit is a more productive composting set-up and ideal for large amounts of yard and garden waste. This unit is at the Briggs Avenue Community Garden in Durham, which is on land owned by NC State and maintained with the help of Extension master gardeners. photo credit: Andrea Laine

Benefits of Composting
Compost improves the physical properties of the soil:  its color, texture, structure, depth, and water capacity. Compost also supplies the soil with essential nutrients, mainly nitrogen and carbon. Nitrogen supports foliage growth and green color; It easily leaches from soil so it is important to replenish it. Carbon improves soil aeration, and water drainage and retention.

Composting is easier than I imagined it would be and helpful in so many ways. It is an excellent way to recycle yard trimmings and natural kitchen scraps year round. I no longer feel guilty about fruits or vegetables going bad before I have a chance to eat them; What does not feed me will feed my compost pile and, ultimately, my garden.

Home-made compost saves money. With a little effort and consistent attention, the pile builds up and breaks down quickly. Thus, I almost always have compost when I want it. Each spring I treat perennials and shrubs by working a shovelful in to the top few inches of soil under the plant canopy.

Siting and Building a Compost Pile
There are two ways to start backyard composting. You can purchase a commercially-manufactured bin or build your own enclosure. I have tried both types and much prefer the DIY approach as it is easier to maintain, especially when it comes to balancing moisture and aeration levels which are important components to a productive pile. A 4×4 cubic-foot enclosure is ideal. The sides must not be solid so air can pass through and around the pile.

Choose the right site for your composting. The first time I tried composting I placed my pile at the rear of a long, narrow acre. Its distant location, behind a shrub border no less, turned out to be inconvenient and, therefore largely ignored. My current pile is just behind a detached garage, out of sight yet still easy to access.

my compost structure
I used four shipping pallets to build my compost bin. Three of the pallets are crudely fastened in two places, using a wood block and nails, to provide structure. The slatted sides provide aeration. The fourth side is purposely unattached so I can access the pile to aerate or shovel out ‘finished’ compost. Photo: A. Laine

It takes about three to six months to produce finished compost using the “hot pile” method. The “cold pile” method will take about a year or longer. The difference being the temperature and moisture of the pile. Compost is ready to use when it is dark brown, has a light and crumbly texture similar to potting soil, and has a pleasant, earthy scent.

compost thermometer
Pile temperatures must exceed 131°F to kill most pathogens harmful to humans and pets, and they must surpass 145°F to destroy most weed seeds. Any kind of thermometer will do for this purpose. Photo: A. Laine

Feeding a Compost Pile
Ideally, begin with a layer of twigs and small branches to provide some structure and ventilation at the bottom of the pile. On top of that, add a layer of dead leaves and then a handful of soil to initiate microorganisms.

Contributions to the compost pile are commonly characterized as “browns” and “greens.” Browns are sugar-rich carbon sources that provide energy to microorganisms. Greens are protein-rich nitrogen sources that provide moisture to microorganisms. Composting works because microorganisms in the pile (such as bacteria, fungi, algae, protozoa and nematodes) feed on this brown and green matter, converting it to what we recognize as soil.

compost carbon
Decaying branches from the woodland floor are great ‘brown’ additions to the compost pile. Photo: A. Laine

Materials I often add to my compost pile include:  coffee grinds and tea bags, dryer lint and floor sweepings, fruit and vegetable peelings, stems from herbs, flower stalks and dead blossoms, egg shells, and twigs that litter the ground. Since Durham County has a very good curb recycling program, I route my newspapers, cardboard and other paper scraps to the recycling bin. The nitrogen content of paper is low and would slow the pile’s decomposition rate, so it is best not to compost paper. Avoid pine needles, too; their waxy coating resists decay. I err on the side of caution and do not add weeds to my compost.

ceramic pail
You can purchase a decorative ceramic pail like this one for about $25, or a plastic utility bucket with handle for $5. Whatever you choose, make sure it has a lid to contain odors, and commit to emptying it regularly. photo: A. Laine

Tips for Composting Success

  1. Piles three to five feet high stay hot best.
  2. Smaller pieces compost faster; Take the time to cut deposits into two-inch pieces.
  3. Turn the pile weekly to aerate it and hasten breakdown of material. If it is too difficult to turn, at least poke holes in it. I use a pitch fork, but there is such a tool as a composting fork that may be easier/better.
  4. Add a handful of soil every now and then to initiate microorganisms.
  5. Occasionally, I add water to the bucket of household waste before dumping it on the pile; approximately 40 to 60 percent moisture is needed in the pile. (Water in the bucket also helps to fully empty its contents.)
  6. Rinse eggshells and set them aside. Once fully dry, crush them to hasten their breakdown.
  7. Pour a layer of dead leaves or rotting twigs (‘browns’) over fresh vegetable trimmings (‘greens’) to dissuade critters from entering the pile.
  8. Strive for a ratio mix of 2:1 “brown” to “greens.”
  9. Animal manure may contain composting-resistant herbicides. See NC State Extension publication Herbicide Carryover in Hay, Manure, Compost & Grass Clippings: Caution to Hay Producers, Livestock Owners, Farmers & Home Gardeners if you add manure to your pile.

Conclusion
I love having a compost pile for its utility in providing nutritious soil for my garden and a place for the recycling of vegetable trimmings, egg shells, and other organic household waste that would otherwise end up in a landfill somewhere. I can, and do, compost year-round. During cold weather the pile is unlikely to get hot enough to break down new additions. No worries though; Being North Carolinians, we know that warm weather will soon return.


References and Resources
How to build a compost bin: http://www.calrecycle.ca.gov/publications/Detail.aspx?PublicationID=347

The do and don’ts of adding matter to a compost pile: https://content.ces.ncsu.edu/backyard-composting-of-yard-garden-and-food-discards

A list of Extension publications on home composting: https://composting.ces.ncsu.edu/home-composting/

Soil and the carbon cycle: http://nmsp.cals.cornell.edu/publications/factsheets/factsheet91.pdf