Compost Evaluation and Winter Worms

The Washington County Fair is mentioned elsewhere in this issue, so I won't dwell on it here. It was fun to work with many Master Gardeners, and to meet folks bringing in vegetables. Above all else, the real highlight of the Fair was to see the delight of 5-year old Oliver, who had entered a sunflower seed head. He proudly told me how he had planted it, watered it, and now it had won a ribbon. The color of the ribbon was not important. The beaming smile on his face was proof positive that the fair was a rewarding experience for him. That genuine sense of awe that comes from a youngster partnering with Nature and following through is what I will long remember about this year's Fair.

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Compost Quality—All compost is not alike! Even though it is all derived from organic material, it can be very different in quality. Quality of compost is determined by what goes into the pile and the process itself. High quality compost is microbial diverse, stable, and mature. If you are buying compost, ask for some kind of an analysis that addresses these factors.

Microbial Diversity -- In addition to compost being full of nutrients, you should expect your compost to be high in microbial diversity. These microbes will include bacteria, fungi, actinomycetes, and Pseudomonas. These organisms are there to digest the organic matter in the soil, make the minerals available for the plants, and help to detoxify the soil. Compost with high microbial diversity will be more complete and responsive in its role of ameliorating the fluctuating and stress situations in the soil.

Compost stability refers to the degree to which the organic matter has been decomposed into more stable materials. In stable composts, the rate of further decomposition is very low and very little carbon dioxide is being given off. If you buy compost that contains large pieces of organic matter, or if it still heats up, you do not have high stability compost.

Compost maturity is another way of evaluating compost quality. It is a measure of how toxic the compost is when tested on germinating seeds. Immature composts contain more growth inhibiting compounds like salts, phenolic compounds, ammonia, and organic acids. Look for composts that are very fine and granular.

Winter Worms – If you are using red wigglers to eat your garbage, then start to think about how you will help them survive over the winter. If your worm box gets below 40 degrees, you may lose worms and they will not be eating very much garbage. I leave some worms outside for the winter, but I cover them heavily with straw and other materials. I also put many worms into the proper worm medium in 20-gallon containers and bring many in to my furnace room. It is convenient for feeding them the peelings and other kitchen scraps over the winter, and they survive and reproduce very well.

Soil Testing Time

It's a good idea to get a late summer soil test, and apply appropriate fertilizers with the fall/winter cover crops. Over the past 5 years I have looked at hundreds of Arkansas Soil Test Reports for gardens. I am aware that many gardeners, who get the soil test, don't fully understand the report. And further, many gardeners have a still harder time making the necessary calculations to figure out what organic fertilizers to use and how much to apply on their beds. It's not my goal to try to explain all the details in this article, but as some of you move to organics, and are using the Arkansas Soil Test, here are some guidelines.

Taking Soil Samples: First, get some soil boxes from the Extension Service. If your garden is small and fairly uniform, one sample will be sufficient. That pint box should be filled with soil from subsamples taken from 5-10 different places in the garden. Don't include the coarse material on the soil surface. Take those subsamples from the 2-6 inch layer of soil. For larger and/or more variable gardens, include more samples. When submitting the samples, explain specifically that you want a test for Nitrogen. The test results will take 2-3 weeks, so plan ahead.

Interpreting the Soil Test Report: Compared with some other states, I really like the Arkansas test results. They do the analysis of 11 different elements and give the results for each element in actual pounds per acre. I have also checked and the Lab results are consistent, i.e. we get the same results from duplicate samples from the same soil. They also provide the soil pH and the estimated base saturation (i.e. the soil Cation Exchange Capacity). The CEC is a measure of the positive minerals (Ca, Mg, K, and Na) in the soil that are attached to the clay and humus particles. For growing nutrient dense produce, you should have those elements in specific ratios.

The soil pH measures the acidity or the alkalinity (i.e. sweet or basic) of the soil. Soil pH of 7.0 is neutral. Lower numbers are acidic and higher numbers are alkaline. For most vegetables, strive for a pH of 6.4 (slightly acidic). Some plants like blueberries, azaleas, and rhododendrons like a more acid soil. Lime raises the pH. Sulfur, sulfates and acetic acid (vinegar) will lower the pH.

Caution: There are some things in the report that are superfluous: Under the Nutrient Availability Index section you will see concentrations in ppm. That means parts per million, and is the number that the Lab determines from their chemical analysis. If you multiply the ppm by 2 you get the pounds per acre. It is based on the assumption that an acre of soil (7 inches deep) weighs 2 million pounds. As a gardener, you have no need to use the ppm values.

You will also have an Estimated Soil Texture name, which is not a real soil texture measurement. It comes from looking at the CEC, which comes from the amount of clay and humus in the soil. The higher the CEC, the more likely you will get a soil texture classification of "clay." You can get the same classification with highly organic soils without any clay in the soil. Just ignore the soil texture name provided.

Be alert that the recommendations for application of Nitrogen are not specific to your soil. I have 6 recent Soil Reports with corresponding rates for Nitrogen of 0, 54, 62, 214, 262 and 596 pounds per acre, and the recommendation for adding nitrogen is identical in all of them. The fact that you get a recommendation for nitrogen, even when they do not do a nitrogen test, should put you on high alert that this recommendation is not meaningful.

Critical Numbers: More than anything else, I look at the pounds per acre for each of the 11 elements. How do you know what the "right" pounds per acre numbers should be? I have spent a lot of time analyzing that tough question. Because I am most interested in recommendations that are developed for growing nutrient dense produce, I have had to go to another source outside of Arkansas for the answers. Pounds per acre numbers for nutrient dense produce have been developed, originally by Dr. Cary Reams, and subsequently by many others. Unfortunately, the Arkansas soil test methodology (the Mehlich 3 system) is different than the soil tests used by Reams and others (the Morgan soil test system). In essence, a stronger acid is used for extraction of the elements in the Mehlick 3 system.

To figure out the corresponding pounds per acre numbers for nutrient dense produce for the Arkansas test, I have collected soil samples, mixed them very well, split them in two parts, and sent each part of the sample to the Arkansas Soil Laboratory and a private laboratory (International Ag Labs) that does the Morgan test and has the pound per acre numbers for growing nutrient dense produce. With the pounds per acre numbers from 17 split samples from both labs, I have now derived estimates of pounds per acre needed for each element that are most appropriate for the Arkansas test. This project is continuing.

As a rule, the soil tests will reveal 3 to 5 elements that need adjusting. I have seen the test results and there are big differences in pounds per acre for elements among different garden soils. Without the soil test, making fertilizer recommendations is simply a guess. Don't gamble with your garden. Above all, don't start adding fertilizers indiscriminately to new garden areas with native soils. I have seen several examples where the gardener "ruined" the soil by over fertilizing. As a rule, new soils, even if they are low in nutrients, can be easily adjusted. Get the soil test, and if you want help in deciding what organic fertilizers to apply, please contact me.

Fall Gardening - Nutrition Matters

Fall gardens: August is the time to get some vegetables and fruits ready for the Fair, which begins on August 31. It's also the time to get the fall vegetable garden established and plan for a cover crop for the winter. For the cover crops, I use Oats and/or Austrian Winter Peas. You probably won't find them in less than 50 pound bags. I will have oats and peas available in small bags for 100 to 500 square feet areas. If interested in a small amount, let me know. Both of those cover crops should be planted in early September.

For the fall vegetable garden, I plant beets, carrots, broccoli, cabbage, Swiss chard, lettuce, radishes and turnips. Although it will still seem very much like summer, mi to late August is the time to begin fall gardens. Only a few nurseries will have broccoli and cabbage plants available, and they don't last long. If you want to grow your own, start them in early August. I plant seeds of these in the garden and then transplant them later. Because these are cool weather crops, they will benefit from a little afternoon shade.

Nutrition matters: For the majority of the time that I spend helping other organic gardeners, I deal with questions regarding the re-mineralization of the soil (fertilization). Growing vegetables is not the same as growing vegetables with high nutrition, which I advocate. In a good fertilizer regime all the minerals needed for good growth and nutrition are there in their proper amounts. What to apply depends on what is already in the soil. Without a soil test, it's pretty much a guess. Sometimes it is an easy process to get the correct amounts and ratios, but in general the process of getting all the minerals and ratios correct takes several years.

Boron is more than a minor element. It is fortunate that in our Arkansas Soil Test program we get a test for the mineral or element called boron. Like many minerals, boron does not act independent of other minerals. It is closely tied with calcium, and in fact calcium will not provide its many benefits if boron is in short supply. It begins with its role in photosynthesis, i.e. the production of sugar. Next, it plays a critical role in releasing sugar to the root system each night. This sugar exudes from the roots and feeds the microbes in the rhizophere, which in turn helps to fix nitrogen, make phosphorus soluble, recycle minerals from crop residues, remove toxins, produce growth stimulants, and protect the plant from pathogens. All this and more is partially dependent on the correct amount of boron.

Although the Arkansas Soil Test program provides the pounds per acre of boron in the soil, there are no recommendations given for adding boron, even if the values for boron are zero. It is important that you look at this number on your soil test report each year and add boron if needed. Boron is a mineral that is leached from the soil, especially in soils low in organic matter.

You can fix the boron deficiency problem easily by simply adding borax (yes, the Twenty Mule Team product). Four pounds of boron per acre is adequate. Do not over supply, especially in calcium deficient soils. Borax is 12 percent boron, so for each pound per acre that you are deficient in boron, add 1 Tablespoon of borax per 100 square feet. Mix it in water, apply, and water it in. It can also go on as a foliar spray, and is especially helpful if done prior to flowering.

Boron is not just for the welfare of the plants and the soil. Animal and human health nutritionists now know that it serves in a diverse range of functions in animals and humans. A shortage in the diet can lead to health issues. It all begins with having it in the soil. Want to read more about this, check it out on the internet. See nutri-tech.com.au for starters.