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Features (Green Living)

Even with compost you can overdo it

Recently a Bay Weekly reader complained she could not grow cauliflower or broccoli. The plants grew big and lush but never produced edible heads — all this despite the large amount of compost she added to her garden soil each year.
    My response was too much of a good thing. Compost is a good source of not only long-lasting fiber but also slow-release nutrients. For every percent of organic matter in soil, an acre of soil generates 10 pounds of nitrogen each year. If your soil contains five percent organic matter, that translates to 50 pounds of nitrogen per acre per year.
    Growing a good crop generally requires between 100 to 120 pounds of nitrogen per acre per year. If your soil contains 12 percent organic matter, you should not have to apply any nitrogen fertilizer to achieve optimum plant growth — providing all other nutrients are present at optimum levels. If your garden soil contains 15 percent organic matter or more, plants are likely to produce super-lush growth. Leafy plants such as lettuce, cabbage, spinach, Swiss chard, celery and fennel should produce bumper crops. Cauliflower, broccoli, tomatoes, peppers and okra will likely produce large vigorous plants but limited fruit.
    This same problem occurs when you apply too much nitrogen fertilizer. Several years ago a Bay Weekly reader complained that his tomato plants grew like trees but hardly produced any tomatoes. As I was not able to diagnose the problem, based on our discussion over the telephone, I invited him to Upakrik Farm and requested he bring the bags of fertilizer he used. He brought a bag of 10-10-10 and a bag of urea. He said he used urea and not calcium nitrate as I had recommended in one of my Bay Gardener articles because the store manager said calcium nitrate was not available but urea would substitute. Urea contains 45.5 percent nitrogen while calcium nitrate only contains 15.5 percent nitrogen. In other words, the excessive amount of nitrogen from the urea caused the tomato plants to remain vegetative rather than producing fruit.
    Monitoring organic matter content in your soil is another good reason for having periodic soil tests, which also measure pH and nutrient levels.


Are Strawberries Perennial?

Q If you want to get several years of picking strawberries from the same plants, would you leave them alone after picking or would you mow the top leaves off? I know that the commercial guys plow them under each year and replant for the next year, but I had a decent crop this year and hate to till them in.

–Frederic Ames, Shady Side

A    The traditional method of growing strawberries is to rototill under the mother plants, leaving the daughter plants to produce next year’s crop. By doing so, the same bed can produce berries for three to four consecutive years. However, crown mites, often called cyclamin mites, cause crop failure on the fourth year.


Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

Biosolids are safe for food ­production; here’s why

Since I became involved in composting biosolids in the early 1970s, technology for processing wastewater has undergone major changes. Back then, most wastewater treatment facilities had only primary or secondary treatment technology. At the same time, industries were dumping all kinds of waste into sewer systems.
    The Clean Water Act promoted by president Lyndon Johnson led to major changes that now enable us to convert solid waste into usable products while returning more carbon to the earth. The act stopped wastewater dumping into our streams, lakes, Bay and oceans. It established a Biological Waste Management Laboratory managed by the U.S. Department of Agriculture and the Environmental Protection Agency. Studying the science of composting, this laboratory has developed efficient composting systems.
    The Clean Water Act also mandated that wastewater be returned clean to our waterways. Wastewater processing facilities were upgraded to secondary and tertiary systems. Tertiary systems not only return crystal clear water but also generate biosolids that are classified Class A, meaning they can be used to produce agricultural crops.
    The Blue Plains Advanced Wastewater Treatment Facility in Washington, D.C., is the largest plant using the world’s most advanced water treatment technology. Blue Plains processes 300 million gallons of wastewater each day and generates 450 wet tons of biosolids.
    The biosolids are heat-treated to 350 degrees under 87 pounds pressure per square inch. Then they’re infused with active anaerobic microorganisms, and the material moves into the digester. Anaerobic microorganisms are more aggressive in digesting organic carbon compounds than the aerobic microorganisms active in composting. The biosolids remain in the digester for 18 days before filter presses remove excess water.
    The end product is Bloom, a superior soil conditioner.
    Already self-feeding, its production is moving to energy neutral. The digester generates methane gas, used to cook the biosolids. Blue Plains is also installing solar panels over the sludge activators to reduce operating costs.
    Within three years, similar systems will be operating across the country.
    Advanced wastewater treatment and biosolid digestion are only part of the reason you can now safely use processed biosolids in producing food crops. Hard pesticides such as DDT and Chlordane have long been eliminated from use. Pesticides in home use have limited shelf life and are biodegradable. Along with pharmaceuticals, they are destroyed by microbial systems and by the heat.
    Because iron sulfate is added to precipitate the phosphorus from the water, Bloom is not 100 percent organic under current guidelines.
    Bloom is now sold at Homestead Gardens.


Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

Death by herbicide is the first step toward no-till farming

This spring, Chesapeake Country meadows turned from green to the color of straw. It’s been a strange sight and one you’ll see more of in coming years. No, it’s not a symptom of climate change. It’s a step in no-till farming.
    No-till farming offers many advantages over conventional farming.
    Plowing, disking and cultivating destroy soil structure and organic matter and cause soil to compact and to lose moisture, thus requiring ever more energy and more powerful equipment. Turned soil is exposed to wind and water erosion. Dormant weed seeds, which infest our soils, are exposed to sunlight, which can give them the push to germination in a few seconds.
    No-till farming, on the other hand, promotes the accumulation of organic matter. With more organic matter, soil needs less fertilizer, keeps its moisture, avoids compaction and is protected from erosion. But the first step, conversion from conventional to no-till, requires greater dependency on chemical weed killers called herbicides.
    The quick spring change from green fields to gold means the vegetation was sprayed with Gramoxin. Gramoxin is a restricted-use herbicide used to kill either annual weeds or a cover crop of winter rye or wheat. The applicator must be certified to use Gramoxin.
    A more gradual change of color over seven to 10 days suggests the chemical herbicide was glyphosate, pioneered as Roundup by Monsanto. This chemical is used most on peren­nial weeds.
    Weed killers in agricultural use generally have a short lifespan. They are applied in ounces per acre and decompose by light, heat and microbes. As no-till promotes the accumulation of organic matter, there is an increase in microbial activity, which helps keep soil productive.
    In no-till farming, the only soil disturbed is a thin slice where both the seeds and fertilizers are injected into the soil. With less soil disturbance, the weed population diminishes with time, thus reducing the need to apply weed killers in the future.
    The immediate advantage is most noticeable during drought years. No-till crops are more drought-tolerant because the soil retains more water.
    It takes about three years before farmers begin to measure the full benefits of no-till farming. As organic matter accumulates, there is less fertilizer needed to optimize crop yields. With less soil compaction, the roots of crops are able to penetrate deeper for water and nutrients.


Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

Silt does not happen by itself

Farmers, homeowners and contractors are all responsible for making silt that clogs our streams, rivers and lakes and pollutes the Bay. Farmers who after harvesting their crops allow the soils to be fully exposed to the weather all fall, winter and spring are guilty. Homeowners who wash down their driveways and sidewalks in place of sweeping them are guilty. Contractors who bulldoze the earth to clear land for roads, homes, shopping centers and more are also guilty.
    Removing the vegetation allows exposed soil to be carried away by wind and water. The lowest point on land that water can travel is sea level. Thus, dust containing sand, silt and clay settles in the lowest points. Moving water carries soil and deposits sand as the flow of water decreases. The silt is carried farther to eventually settle to the bottom of slow-moving streams. Clay floats out into the Bay, clouding the waters and preventing bottom vegetation from growing, as well as carrying nutrients that feed algae that, when it dies, causes eutrophication.
    The early tobacco farmers were notorious for allowing their fields to remain barren after harvesting. Those farming on slopes lost tons of topsoil each year due to erosion. Most of the silt recently dredged from Rockhold Creek originated from old tobacco fields in the watershed. Even now when a sod farm starts to harvest sod, Rockhold Creek runs chocolate-brown following a heavy rain. Coloring the water is the silt in the topsoil that has washed into the creek. Most will settle to the bottom before it reaches the Bay. What enters the Bay are clay particles in suspension.
    The loss of topsoil and the siltation of our rivers and streams can be prevented by never allowing soil to stand exposed. As soon as a crop is harvested, the land should be planted either with another crop or a cover crop of wheat, rye, millet, Sudan grass or buckwheat. This rule applies to the home gardener as well as to farmers.
    When farming on slopes, contour-farming practices should be applied together with strip-crop farming. Strip-cropping plants wide strips of grass between plots of cultivated crops. The grass strips prevent the sand, silt and clay from washing away.
    Buffer zones or riparian strips of 125 to 150 feet wide of grasses or natural vegetation should be required between cultivated fields and open bodies of water. I encourage farmers to build berms of compost two feet high and two feet wide planted into tall fescue on the riparian strip. Compost is an ideal natural filter that will absorb clay and keep nutrients from flowing to the water during heavy rain.
    It should be unlawful to clean the driveway and sidewalks with water. That water carries dirt, oil, animal droppings, etc. into the storm drains. All storm drains empty into nearby streams that eventually flow into the Bay. A good push broom not only provides exercise but also pushes all of that crud onto the lawn or garden, where it becomes part of the soil. Oil will be degraded by the microorganisms in the soil.
    Before any construction begins, contractors should be required to establish a buffer zone around the construction site and install a silt fence with Filtrex filled with compost on the low side of the silt fence to capture the clays and nutrients. Compost has been proven to be an excellent filter of clays and nutrients. If the silt fence is to remain in place for more than a year, the Filtrex should be seeded with tall fescue to use the nutrients absorbed by the compost. Only clean water should be allowed to exit construction sites.
    If we all did out part in keeping soil where it belongs, our agricultural soils would be more productive, there would be less need to apply fertilizers and the water in our streams, rivers lakes and the Bay would be crystal clear and blue as it was meant to be. Progress should not be measured by polluted water or by polluted air.


Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

Bloom is the best thing to come out of D.C in a long time

The demand for organically grown food continues to increase. Because chemical fertilizers cannot be used in its production, growers must depend on natural sources for nutrients, such as animal manures, compost and green manure crops. The demand for compost is so great that it exceeds the supply.
    The problem may soon be solved by recent developments in processing biosolids.
    Biosolids are the solid materials derived from wastewater processing facilities, also known as sewage-treatment plants. Yes, you know what I’m taking about.
    Yet wastewater treatment has advanced so far that 85 percent of the biosolids in the U.S. satisfy EPA Class A standards. Class A biosolids can safely be use in the production of agricultural crops.
    The Blue Plains Advanced Wastewater Treatment Plant in Washington, D.C., is the largest plant of its kind in the world. The biosolids generated there are rich in Capital Hill bull @#!$. Now plant engineers have perfected a method of converting biosolids into Bloom, an organic matter rich in nutrients.
    First the biosolids undergo anaerobic digestion. Then excess water is removed, and the biosolids are dumped into a giant pressure cooker that is heated to more than 200 degrees. The pressure is released instantly, causing the tissues in the biosolids to rupture, thus releasing their nutrients. Anaerobic digestion degrades all organic compounds, including toxins. The pressure cooker treatment renders Bloom sterile. After the processed biosolid is removed from the pressure cooker, it is dried. The finished product looks black and has an earthy odor.
    I dedicated over 20 years of my career to research on composting. I have studied its value in nutrition and in controlling soil-borne disease. I have used compost on a great variety of plants, from growing garden vegetables to growing forests in abandoned gravel mines to blending rooting media for growing plants in containers.
    Compost has solved many problems, promoted recycling and has created new industries. Yet I have never achieved with any compost the results I am getting from Bloom.
    My method is blending Bloom with compost to combine the superior qualities of both products. I use a rooting medium containing equal parts by volume of peat moss and compost (made at Upakrik Farm) with 25 percent by volume Bloom. Because it contains seven mmhos/cm of soluble salts, it must be applied sparingly. My tests indicate that the maximum is 25 percent in combination with regular potting medium.
    I am testing it in growing broccoli, cabbage, cauliflower, lettuce, onions, peppers and spinach. I have also used it as mulch on half of the garlic plants growing in the garden. Garlic plants mulched with Bloom in late February are darker green and taller than garlic growing in the same bed without Bloom as mulch.

    Pictured above are cabbage and pepper plants growing for eight weeks with no additions but water as needed. The pepper plants that I have been growing are dark green while the cabbage and broccoli plants are a rich blue-green.
    We recently vertically mulched the large oak trees near my home by augering 320 six-diameter holes a foot deep, starting 10 inches from the trunk of each tree to the drip line of the branches. Each hole was filled with Bloom. Within two weeks, the grass surrounding each hole turned dark green and was growing rapidly. I can’t wait to see how the trees respond. I have vertically mulched these trees with compost every seven years with great results. I feel confident these mulching results will be even better.
        Bloom is not only producing excellent results but is also a consistent product day to day, month to month. What’s more, the Blue Plains process can be completed in days. In comparison, composting biosolids takes months from start to finished product.
        If every wastewater treatment plant that generates Class A biosolids were to include this new technology, growers would be better able to meet the demands for organically grown food. Homestead Gardens in Davidsonville is in the process of establishing facilities for drying and processing Bloom.


Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

Anne Arundel County offers just the right raw ingredients

Anne Arundel County has more horses than any other county in the nation. It follows that we also have more horse manure. Some of that horse manure occupies precious landfill space or is dumped near streams, thus contributing to Bay pollution.
    Anne Arundel County landfills also have too much of another organic waste, nitrogen-rich food waste produced by an abundance of restaurants. Like yard debris, neither of these organic wastes should be occupying landfill space. Landfills are costly to construct and maintain. Both food waste and horse manure can easily be converted into compost.
    In the early 1980s, the Bay Gardener was involved in writing the state law that prohibited the dumping of yard debris into landfills and established yard debris composting facilities. One such facility is located near Upper Marlboro, just a mile from the Anne Arundel County line, near the intersection of Route 4 and Route 301. Operated by Maryland Environmental Services, it is one of the locations that manufactures LeafGro.
    Last month, the Anne Arundel County Council and the County Executive approved the composting of horse manure and restaurant waste on South County farms in facilities between five and 10 acres. The legislation has established strict standards that limit the area for compost to 25 percent of total acreage. Prohibited from composting are dead animals or waste from processing facilities. The new legislation also limits proximity of composting pads to adjacent properties, occupied dwellings and streams. The composting must be done on a non-porous pad, and the facility must be managed by an operator certified in the science of composting. The location of any such facility must be pre-approved. Also considered in the legislation is road access to the facility.
    The Maryland Department of Agriculture is responsible for certifying managers of composting facilities. Certification requires a training program and rigorous written exam. As Maryland was the first in the nation to establish a commercial composting training program, I prepared many of the questions that are included in the certification exam. Managers must be knowledgeable in the biological processes, monitoring equipment, standards and management procedures.
    The Maryland Department of the Environment is responsible for inspecting and assuring that the facilities are properly managed and that sanitary conditions are maintained. Maryland’s composting facilities have been operating for the past 30 years without creating problems while producing such compost products as LeafGro, Orgro and Veterans Compost. Many municipalities compost their own yard debris, making it available to residents at a minimal charge, following standards established within their jurisdictions without creating odors. Near Exit 1 on the Baltimore Beltway, a composting facility processes 180 to 200 tons of Baltimore sewage sludge each day without creating an odor problem, producing compost called Orgro.
    Composting is an exact science. It requires blending the proper amount of feedstocks; in this case horse manure with restaurant waste. The amount of carbon and nitrogen in each are determined by established laboratory testing methods. After these two materials are blended properly in the correct amounts and placed in windrows, moisture levels are maintained between 50 and 60 percent and oxygen levels are maintained above five percent. Temperatures within the piles will average between 140 and 160 degrees within 24 to 36 hours. When oxygen levels drop below five percent, the windrows are turned with specialized equipment to introduce more oxygen into the mixture. Some composting facilities draw air, using fans, through the composting piles to maintain oxygen at the proper level. Only when the temperatures within the piles achieve those near ambient air is the compost ready. The process will generally require 80 to 100 days, depending on the time of year and the volume being composted. The resulting compost has a rich earthy smell.
    The microorganisms that digest the carbon in the horse manure, while using the nitrogen from the restaurant waste, are the same microbes found in garden soils. The same process occurs on the forest floor. Science has discovered that under ideal conditions, these microorganisms will gladly work overtime.
    The only by-products of composting are water vapor, heat and carbon dioxide. There are no toxic gasses released during composting.
    Gardening has become the most popular hobby in the nation. Ornamental horticulture is the second largest income-producing agricultural industry in Maryland, second to poultry. Potted plants are all grown in soil-less blends containing one-third to one-half by volume compost. With more people demanding organically grown food, the need for compost far exceeds the supply. Compost is a great soil amendment and a good source of slow-release nutrients.
    I have spent more than 30 years conducting research on using compost made from sewage sludge, animal manures, yard debris, crab waste, garbage, paper-mill sludge and more. Composting is the ultimate in recycling, and it can be done safely and efficiently. Although composting is an old agricultural practice, today’s composting technology is as different as the Model A Ford is to today’s hybrid cars.


Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

Get a fast start with my Gouin brew

This is a great time to activate the compost pile. The fallen leaves are rich in nutrients and organic matter. Mother Nature has been using leaves as natural mulch since the beginning of time.
    I begin with my leaf blower, blowing as many leaves as possible under the branches of the shrubs to mulch them over winter.
    For my compost pile, I then use the lawnmower to chop the remaining leaves by mowing the lawn with the blade set at five inches above the ground, starting from the outer-edge of the lawn and working my way into the center. This pushes the fallen leaves into the center of the lawn where I can harvest them easily and transport them to the compost bin. Chopped leaves compost faster than whole leaves.
    With the garden hose handy to spray water on the leaves as I load them in the bin, I lay a 10- to 12-inch layer of chopped leaves and cover it with a uniform layer of leftover compost from last year. To hasten the composting process, I sprinkle about one cup of urea or ammonium nitrate per 10 square feet of area and water thoroughly. Each layer of leaves covered with compost needs to be wet in order for composting to start. Dry leaves do not compost.
    If you do not have leftover compost from last year, make your own compost starter by adding a shovel full of garden soil to a five-gallon pail. Add one-half cup of cheap dish detergent and one cup of urea or ammonium nitrate fertilizer. Stir the mixture well, and sprinkle it over each layer of copped leaves added to the pile. The detergent will help in wetting the leaves, and the ammonium nitrate or urea will provide nitrogen to stimulate the microbes in the garden soil into doing their duty. Five gallons of this Gouin brew is sufficient to cover about 30 square feet of composting area.
    The larger the compost pile, the better. Compost piles smaller than five-by-five-by-five feet will not generally become very active until next spring when temperatures warm. However because of mass, larger compost piles are capable of generating and maintaining high temperatures all winter long — providing the composting materials remain moist.
    A long-shank thermometer of two feet or more is helpful in monitoring microbial activity. You can also see the effects of microbial activity by simply digging into the pile on a cold day, watching the vapors rise and feeling the warmth of the compost. If you did a good job of preparing the pile, rising temperatures should be measurable in two weeks or less. You should also notice significant reductions in volume as temperatures rise. This means that the microbes are digesting the leaf tissues and generating heat and carbon dioxide.


Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

Treat yellow-green leaves with ­compost or fertilizer

If your hollies are heavily loaded with berries this fall, most likely the foliage will turn yellow-green, downgrading the contrast with the red berries. It takes a lot of energy and nutrients for plants to produce fruit. This is especially true if the branches are heavily laden with large clusters. Heavy-fruiting hollies generally appear chlorotic. This problem can be corrected by applying a nitrogen-rich mulch such as lobster compost, chicken manure compost or lawn fertilizer between the trunk of the plant and the drip line. For hollies, this treatment should be applied now and the trees irrigated weekly until early December.
    If the plants have had pale green foliage all summer long, they most likely are deficient in magnesium. Without soil test results to confirm this diagnosis, I often recommend spreading one-third cup of epsom salts per 10 square feet. Magnesium deficiency is not an uncommon problem with hollies laden with bright red berries.
    Boxwoods that appear yellow-green in the fall often experience excessive leaf drop due to nitrogen deficiency. If the winter is especially severe, many boxwoods will also exhibit bronzing. Both of these symptoms can be prevented by fertilizing the plants soon after the first frost. Applying one-half cup of a lawn fertilizer for every three feet in height or spread is generally adequate. Make certain that you use only a lawn fertilizer that does not contain weed killers. Apply the fertilizer uniformly beneath the drip line of the branches. Since boxwoods are very shallow-rooted, they will quickly respond to the treatment.
    Azalea are also susceptible to early fall discoloration and loss of leaves. Roots are unable to provide sufficient nitrogen for flower-bud development. As a result, nitrogen from the lower leaves migrates upward to the developing flower bud at the tip of the branches. Chlorosis of the bottom leaves is very common on white-flowering azaleas because they flower in abundance. This problem can be solved by mulching them with either Maine Lobster Compost, compost made from crab waste or ammonium sulfate fertilizer. If using ammonium sulfate fertilizer, apply only one tablespoon per two feet of height or spread of the azalea plants. Apply the ammonium sulfate mostly under the drip line of the branches.


What’s Killing My Spruce?

Q    I have a 50-year-old spruce tree that is dying from the bottom up. What would cause this (just old age?) and is there anything that can be done to save it? Thanks for your advice. I love Bay Weekly.

–Mary Jane Gibson, Lothian

A    It is not old age because spruce trees can live 100 years or more. Which spruce is it — Norway, white, black, red, Colorado, Engelmann, Siberian, etc.?  Look at the ground under the branches for holes about the size of a silver dollar. If you see such holes, it is possible that pine mice are girdling the roots. If so, you have to kill the pine mice with poison bait for mice (available at the hardware store). If the trunk is bleeding sap, then the tree is infested with cankers. Or the tree may be suffering from weed killers if you have used them on your lawn.


Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

Yes, but do it at the grocery

Anne Arundel Countians are lucky to have their recycling picked up at the curb. With the county’s single-stream recycling program, you don’t even have to sort. Even so, 26 percent of what goes into the trash is recyclable, according to Anne Arundel County Recycling.
    Getting that quarter of our waste out of the trash stream depends not only on the will to recycle but also our knowledge.
    You can find a list that outlines most of what is and is not accepted for curbside recycling on the website www.recyclemoreoften.com.
    How about plastic bags?
    Reading the website left me confused, so I asked direction from Rich Bowen, Recycling Program Manager for Anne Arundel County.
    Most plastic bags that stretch when pulled are recyclable. This includes grocery bags, bread bags, retail bags (even the thicker plastic retail bags) and newspaper bags. Also in this category are zip-top or roll-top food bags and cellophane plastic wrap.
    Not recyclable in Anne Arundel’s program are shiny metallic bags like chip bags.
    Gather recyclable bags together, please, Bowen asks.
    “For curbside pickup, we ask that residents bundle these bags together and tightly tie the bundle so that they don’t come apart during collection or sorting,” he told me.
    Still, curbside recycling is not the best solution for plastic bags.
    “The best thing to do with them,” Bowen advises, “is take them to the grocery store with you and deposit them in the collection bin at the front of the store.”
    The reason is what happens to the bags after you put them out for recycling.
    “The biggest buyer for bags right now is the company that makes Trex decking,” Bowen said. “The composite lumber material uses the plastic bags to make its product. They want clean bags and feel that when the bags are collected with other materials they get soiled by other recyclables so they can’t use them,” Bowen said.
    Also, if the bags come loose during sorting, they can get lodged in the gears of the mechanism that separates paper, metal, glass and plastics. Escaped bags gum up the works, causing the machine to slow down. This results in a slower processing time, which makes costs for recycling all single stream materials increase.
    Many — but not all — grocery stores have obviously located plastic bag collection bins.


Has a sight stymied you? Does an oddity bewilder? Your curiosity may be featured in an upcoming column. Send your questions to chesapeakecuriosities@gmail.com.
 

Sometimes you need fertilizers

Am I an organic gardener? I’m often asked that question. I suspect that many who read this column conclude that my frequent reference to composting and compost in gardening means I must be an organic gardener. They seem shocked when I say that I use chemical fertilizers in addition to amending my soils with compost. My reasoning is that of a scientist.
    Before my research into compost, my primary area of research was mineral nutrition of plants. My research for the thesis for my master’s degree resulted in the development of a slow-release fertilizer marketed as Osmocote 18-6-12. The three-year study was conducted on yews, a narrow-leaf evergreen common in landscape plantings. At the time, the nursery industry was starting to grow more plants in pots. Nurserymen were using the same fertilizers as in field production. The two are totally different growing conditions. Plants growing in pots require more frequent irrigation, which washes more nutrients through the bottom of the pots. Plants grow faster in pots because of high rooting-media temperatures and better aeration. But the rooting media used for growing plants in pots do not store nutrients well.
    My research and reviews of the results of many other plant-nutrient experts convinced me that it can be very difficult to satisfy the nutrient requirements of plants at different stages of growth.
    My later work in the use of compost in the production of nursery and greenhouse crops reinforced the conclusion that it takes both organic and mineral fertilizers to achieve both plant health and high crop yields.
    In the spring when soils are cool, compost, animal manure and organic fertilizers are unable to generate sufficient nutrients because they require microbial activity to release nutrients. For spring-planted crops such as peas, cabbage, broccoli, onions and cauliflower, chemical fertilizers can provide those nutrients.
    Again when tomato and pepper plants are flowering and fruiting simultaneously, the demand for nitrogen is greater than organics are capable of generating. Plants drop bottom leaves because the nitrogen within them is migrating out of the leaves and moving up the stem. This makes the plants more susceptible to blight.
    In mid-summer when sweet corn is growing rapidly in advance of tasseling, organics are not capable of generating sufficient nitrogen for big, sweet ears. Thus the corn stalks drop their bottom leaves.
    We know from studies on the use of compost to grow bedding plants that the nutrient-supplying power of rooting media containing compost can supply adequate levels of nutrients for only about six weeks.
    Nitrogen is the element plants need in greatest abundance. Organic matter is incapable of supplying all that is needed. Numerous research studies have confirmed my initial research that most plants require five to six times more nitrogen that phosphorus and two to three times more potassium than phosphorus. As day length, moisture and temperature affect plant growth, using the combination of soils rich in organic matter with supplemental applications of chemical fertilizers gives you the best of both worlds.


Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.