Learn With Us, week of October 13

Why We Study Soil – Durham Garden Forum
Tuesday, October 15⋅7:00 – 8:30pm

Sarah P. Duke Gardens
420 Anderson St, Durham, NC 27708
With Dr. David Crouse, Professor & Undergraduate Teaching Coordinator of Crop and Soil Science at North Carolina State University Soil is the basis of all garden success. Dr. David Crouse will outline some of the basic ecoservices provided by soil to give you the big picture of how soil impacts your garden and some specifics about how you can work to improve your soil.

The Durham Garden Forum is an informal group that meets once a month to enrich our gardening knowledge and skill, on Tuesdays, 7:00- 8:30 pm at Sarah P. Duke Gardens. Lectures free for members, $10 general public.
No pre-registration necessary.

Our Straw Bale Gardening Experiment

by Marty Fisher, EMGV

After three painful years of crop-destroying diseases on our beloved heirloom tomatoes, my husband and I decided to give straw bale gardening a try.

I had tried grafting—attaching an heirloom scion onto a hardy root stock—for two years with some success, but it was a long, painstaking process, and we still weren’t getting the yields we enjoyed in the days before the dreaded fungal, viral, and bacterial diseases took over in our garden. We also tried disease-resistant tomatoes like Early Girl, Better Boy, Celebrity, Sweet 100, etc., but we missed the complexity of flavors and variety of colors of our favorite heirlooms like Carbon, Amana Orange, Green Zebra, Pineapple, Lucky Tiger, and more. We also tried removing the lower branches of our plants to keep them away from disease spores in the soil as well as spraying with copper sulfate—it all seemed a lot of work for a limited return on investment!

I started researching straw bale gardening in January, thinking it offered the advantage of a sterile environment for the tomato plants as well as the effect of a raised be d. I found a book written by the man who pioneered the concept, Joel Karsten. He came up with the idea after observing healthy, vigorous weeds sprouting in old straw bales on his family farm. He began experimenting with vegetables, and over decades, developed the techniques for gardening with straw bales. Since then, he has published two editions of his book, Straw Bale Gardens, and has spoken all over the world about what is touted on the book jacket as “the hottest new method of veggie growing.” The book contains a wealth of useful information, plans, diagrams, and more.

Our first task was to find straw bales—they must be wheat straw bales, not hay. They are not cheap, especially given the size of our garden. The best price we found was about $6 a bale. We inquired about delivery and were told by several farm supply stores that they sell the bales at a loss or break-even and were not interested in delivering them. So, several pick-up truck trips later, we had lots of bales on our garden site. 

The next step was placing and conditioning the bales, a process that takes 10-12 days. Conditioning should be started two weeks before the average last frost date. 

Although I had reservations about the fertilizer recipe given in the book, we decided to just follow the instructions and evaluate the results. Over the conditioning period, fertilizer and water are applied to the bales according to a day-by-day schedule. My reservation concerned the recommendation of nitrogen-rich “traditional refined lawn fertilizer.” Instructions are also given for organic nitrogen sources, but this seemed more complex, and we followed the conventional method. Fertilizer is sprinkled over the top of each bale, and water carries it deep into the bale, starting the bacterial process of breaking down the bales to release nitrogen.

On Day 10, the instructions call for one cup per bale of 10-10-10 general garden fertilizer, watered in. 

Planting can begin on Day 12. A little sterile potting soil can be used to anchor the plant in the straw bale, but all the nutrients and growing medium the plants will need are contained within the conditioned bales. Adding garden soil or compost could introduce fungal spores to the sterile bales.

Results  

Our concerns about using lawn fertilizer were confirmed over the spring and early summer: TOO MUCH NITROGEN! Our plants quickly became enormous, with fewer blooms than normal. They also began to shade out the eggplants and herbs that we had planted beside the tomato plants. We added a phosphorous- and potassium-rich fertilizer and gradually the plants started to have more blossoms and bear fruit. We also noticed that plants growing in straw bales require more diligent watering. Karsten recommends placing soaker hoses on top of the bales, controlled by a timer. 

In researching this article, I found an N.C. Cooperative Extension Service article (see “Hay” Bale Gardening link below) that recommends a different conditioning method. It calls for simply watering the bales for three days. On Day 4, you add 2 cups of dolomitic limestone and a half cup of ammonium sulfate, and water it in. On Days 5-9, you add more ammonium sulfate, followed by a cup of 10-10-10 or 8-8-8 on Day 10. Planting commences on Day 11.

This year we did lose a few plants to “the *%#* fungus,” our common term for fungal, viral, and bacterial diseases including early blight, late blight, fusarium wilt, tomato spotted wilt, various cankers—you name it. My husband also sprayed the plants with copper sulfate as a preventative. 

Overall, we deemed the straw bale gardening experiment a success. We canned, made salsa, roasted, sliced, and froze plenty of colorful tomatoes to get us through the winter. We plan to try it again next year using the Extension Service-recommended fertilizer recipe.

I also plan to graft tomatoes again next year after taking this year off. And, I’ll give some of the newer disease-resistant varieties a try. Some I’m particularly interested in include Iron Lady, described as “super resistant,” and Mountain Magic, which was developed by Dr. Randy Gardiner, professor emeritus at North Carolina State University. Apparently, some breeders are also developing disease-resistant heirlooms, including two old favorites of mine, Lemon Drop and Mr. Stripey.

This was our first harvest this year–it got better after we adjusted the fertilizer.
Good old fashioned canned tomatoes! Heirlooms make the jars so colorful.
Tomatoes growing in straw bales in our garden. In addition to diseases, we also battle squirrels, hence the large cage under construction.

All photos taken by Marty Fisher.

Sources

Straw Bale Gardens Complete, by Joel Karsten

Understanding Tomato Varieties:
https://lee.ces.ncsu.edu/2019/05/understanding-tomato-varieties/

How to Grow Better Tomatoes
https://forsyth.ces.ncsu.edu/2018/05/how-to-grow-better-tomatoes/

Grafting for Disease Resistance
https://content.ces.ncsu.edu/grafting-for-disease-resistance-in-heirloom-tomatoes

Blight Resistant Tomato Varieties Worth Growing
https://www.growveg.com/guides/blight-resistant-tomato-varieties-worth-growing/

“Hay” Bale Gardening
https://pamlico.ces.ncsu.edu/2013/05/hay-bale-gardening/

Core Aeration of Lawns

by Carl J. Boxenberger, EMGV

Core aeration is a process by which cores or plugs of soil and thatch are removed from the lawn. Core aeration is done by a machine with hollow tines.

Soils that are prone to heavy traffic are subject to compaction. Core aeration reduces soil compaction by removing plugs of soil which opens up a channel in the lawn and allows water, oxygen and nutrients to penetrate down in the soil.

Core aeration should be done when the grass is actively growing. Fall is the time to core aerate cool season lawns such as tall fescue. Spring and early summer is the time to core aerate warm season grasses such as Bermudagrass.

Gardener operating soil aeration machine on grass lawn. Stock Photo c Mikhail Pavlenko

Core aeration equipment with hollow tines can be rented at local equipment rental companies.  There are also professional turf maintenance companies that will aerate your lawn if you do not want to tackle this by yourself.

Run the aeration equipment over your lawn to remove soil cores. Chop up the cores by running a lawn mower over them. If you have a large lawn and a tractor, you can distribute the cores by dragging a piece of chain link fence or mat over them.

Core aerate a few days after a rain. This will have allowed the soil to drain. If you pull plugs when the soil is wet they will form wet clods of soil alongside the aeration holes and actually inhibit air infiltration into the soil, defeating the purpose of aeration.

Further Reading

NC State Extension Turf Files: https://www.turffiles.ncsu.edu/

News alert about zoysiagrass mite damage
https://ncturfbugs.wordpress.ncsu.edu/2019/05/23/zoysiagrass-mite-alert/

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