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Features (Gardening)

Clean up to improve next year’s crop

Tomato blight attacks your tomatoes by way of the leaves. The blight starts at the bottom of the plants and progresses upward. The lower leaves turn yellow-green, and oblong spots with concentric rings in the middle appear mid-leaf. Soon the leaves brown and fall. Plants are weakened and, without shade, fruit sunburned. So you don’t want to give the blight a foothold, for it will spread.
    If you have tomato plants still in the ground, destroy any that are contaminated; avoid composting unless  temperatures in the  pile exceed 140 degrees.
    If you have already placed your tomato cages and stakes in the garden shed, you may want to take them out of storage for treating.  The spores of tomato blight can overwinter on the wire cages or stakes that support plants during the growing season.
    A recent research study demonstrated that tomato plants grown with new cages and new stakes have far fewer incidences of blight than plants grown with previously used cages and stakes. Microbiologists were able to culture spores of the organisms that cause blight in tomatoes from cages and stakes in both fall and spring.
    But treating used cages and stakes with a diluted bleach solution prior to storage and before placing them around the tomato plants in the spring significantly reduced the blight problem, the researchers also reported.
    They recommend spraying the cages with a 10 percent bleach solution (one part by volume of bleach and nine parts by volume water). Spray the wires until they drip, making certain that the joints are thoroughly soaked. If you use stakes, dipping them in the same percent solution brings the bleach into all of the pores of the wood, plastic or steel. Vessels for dipping can be made from a large diameter piece of plastic pipe or a piece of gutter capped at one end. Wear latex gloves to avoid skin contact with the bleach.
    Growing tomatoes in the same soil where potatoes were grown the previous year also resulted in greater occurrence of blight in tomatoes, the researchers reported. The blight appears to be carried over on the unharvested small potatoes left in the ground. If you grow both tomatoes and potatoes in the same garden, let a full year lapse before rotating tomatoes to where you previously grew potatoes.


Ask Dr. Gouin your questions at DR.FRGouin@gmail.com. Please include your name and address.

A cover crop of winter rye is the ultimate in nutrient recycling

Planting a cover crop in your garden is good for the soil. It also contributes to improving the quality of Bay waters. Soil should never be exposed to rain and wind. Most of the brown, muddy water you see while boating on the Bay is colored by soil that has washed from adjoining lands or streams.
    As soon as you finish gardening in late summer and fall, plant winter rye in your garden. Winter rye is a great scavenger plant because it absorbs all available nutrients and stores them in roots and stems. Since it is deep-rooted, it absorbs nutrients that have leached down in the deeper soil, and its roots help to fracture the hardpan soils created by repeated plowing or rototilling. Its roots are rich in lignins, fibers that are slow to decompose and that improve soils making them more friable, thus more suitable for growing plants. Then, when the roots, stems and leaves of rye plants are plowed or rototilled into the ground, they decompose, providing nutrients to the plants in your garden next season. In other words, cover crops, often called green manure crops, are the ultimate in nutrient recycling and the best in preventing the loss of soil and nutrients by wind and rain.
    The complaint that I hear most often from gardeners who have tried winter rye as a cover crop is that it is difficult to turn under in the spring because it makes very dense vegetation. This is a self-inflicted problem because those gardeners have applied too much seed. The application rate of winter rye seed to establish an effective cover crop is one to one and a half pounds per 1,000 square feet. This information is often printed on the package, but who reads directions?
    Mow the winter rye before plowing or rototilling the garden, and you’ll achieve good incorporation of the chopped stems and roots with one or two tries. 
    It takes approximately two weeks for the decomposition to start releasing nutrients, so I advise preparing the soil two to three weeks in advance of planting. The soil will be exposed during this short period, but the roots will help retain it. What’s more, microorganisms will actively be fixing any available nutrients in their effort to decompose the new organic matter.
    Topsoil is a precious commodity and natural resource. Keep the soil where it belongs and out of Bay waters.


Ask Dr. Gouin your questions at DR.FRGouin@gmail.com. Please include your name and address.

Here’s the one way to kill kudzu and bamboo

These very invasive species cannot be killed by spray during the summer months. They grow so rapidly that the week killers knock back only the top of the plants and not the roots.
    To kill the roots of perennial plants, the weed killer must translocate downward into the roots and rhizomes. For kudzu, you need only to kill the roots. For bamboo, you must kill both the roots and the rhizomes, the underground stems from which new bamboo canes appear.
    Only during the later part of October and early November does the food produced by the foliage of both these invasives translocate down into the roots and rhizomes. The combination of shortened daylight hours, warm days and cool nights sets the stage. In early fall, these plants build up a food supply in their roots so that they can generate strong growth the following spring when soils warm and daylight grows longer.
    Spray when foliage on the plants is abundant. Choose a bright sunny day when the soil is moist so that the foliage to be sprayed can absorb the weed killer.
    Follow the recommendations provided by the manufacturer for mixing glyphosate (Roundup) with water. To assure greater penetration, add one teaspoon of ammonium sulfate to each gallon of spray to be applied. Wear protective clothing and rubber boots to thoroughly wet the foliage. Use low pressure and a coarse spray to avoid drift. Cover nearby desirable plants with plastic sheeting. Repeat the spray treatment in seven to 10 days. 
    The kudzu vines will die back to the ground as usual, and if you do a thorough job of spraying, they will not be resuming growth next spring. The bamboo will show signs of dying in about one month following the second application. If you followed the directions, you should not observe any new growth of bamboo next spring, except perhaps at the outer edge of the planting. This can be a problem when there is not adequate bamboo foliage that can be sprayed. If this occurs, allow that bamboo to grow uninterrupted next summer and repeat the treatment that fall.


Ask Dr. Gouin your questions at DR.FRGouin@gmail.com. Please include your name and address.

The bulbs grow fat when the days grow short

I have a favorite treat in June: going into the garden and lifting out a big bulb of elephant garlic for roasting. Eat a few crackers smeared with fresh roasted elephant garlic and you will think you’ve died and gone to heaven. If you wish to enjoy that heavenly food, now is the time for planting.  
    Garlic thrives in full sun in well-drained soil rich in organic matter. To prepare for planting, spread a layer of compost about an inch thick over the garden soil, add a dusting of agricultural limestone over the compost and spade or rototil to a depth of at least six inches.
    To grow large bulbs of elephant garlic, space the cloves at six-inch intervals in rows six inches apart. Using a dibble or a narrow trowel, dig holes three to four inches deep with at least one inch of soil over the top of each clove. Plant the cloves with the blunt side down and the pointed side up.
    In about three to four weeks, young, yellow-green leaves will emerge from the soil. Keep the garlic plot free of weeds. Do not apply any herbicides.  
    If your interest is in growing standard-sized garlic — Italian, German red or greater white, for example — prepare the soil as described above but space the cloves four inches apart in the row with rows six inches apart.
    Garlic is a short-day plant, forming its bulb during less than 12 hours of daylight. If you were to plant garlic cloves in the spring, the plants would only produce leaves and no bulbs.
    With mid-October planting, leaves should be four to six inches tall by mid to late November.
    Just before the ground freezes, spread a two-inch thick layer of compost over the soil and water into place. The compost will serve as a mulch, and next spring it will supply the nutrients the garlic plants will need to grow large bulbs. The nutrients contained in the compost will leach out of the compost with each watering.
    Garlic is a rather coarse feeder, meaning that its limited root system depends on a readily available supply of nutrients.  
    If the foliage develops a yellow-green color in mid May, this is an indication that the plants lack nitrogen. Apply one-fourth to one-half teaspoon of calcium nitrate, ammonium sulfate, urea or bloodmeal per plant over the mulch and water it in. A healthy green color should return in a week or two.


Ask Dr. Gouin your questions at DR.FRGouin@gmail.com. Please include your name and address.

Next year’s flowers and vegetables thrive on what you do now

The leaves of herbaceous perennials are turning yellow with their margins already crisp-brown. Trees and shrubs have stopped growing leaves; winter bud scales are well developed over the buds in the axils of their leaves. Perennial plants are getting ready for winter.
    Annuals, too, are dying. When your annual flower garden is at the point of no return, set your lawn mower to its highest level and mow down those dead and dying plants. Mowing creates a mulch and keeps stems in place to catch and hold leaves. The roots of those dead plants will decompose in place and create tunnels for the roots of next year’s annuals to follow. Leaving those tunnels is one more reason not to spade the garden next spring. Another? Spading allows weed seeds to germinate by exposing them to light.
    Turning to the vegetable garden, cover the earth over winter by planting a cover crop of winter rye at the rate of seven to eight pounds of seeds per 1,000 square feet. The rye will capture nutrients not absorbed by this year’s crop. As well as preventing nutrients from entering the Bay, the cover crop crowds out winter weeds and holds the soil in place. When you plow the cover crop under next spring, it will release those nutrients back into the soil. The decomposing cover crop will also improve both the nutrient- and water-holding capacity of your soil and reduce its density, which will result in improved root growth.
    If your day lilies, peonies and hosta are crowded, fall is a great time to divide them and extend your garden or share them with neighbors and friends. For showy flowers in May, transplant peonies shallow, making certain that the eyes, the flower buds, are at grade and not covered with more than one inch of soil.
    To assure a bumper crop of asparagus spears next spring, neglect the bed until all of the stems have turned straw color. That’s the sign all of the nitrogen that has accumulated in the stems and leaves has drained down to the roots.  Next spring when the buds start growing, there will be a readily available source of nitrogen for that first burst of spears.


Ask Dr. Gouin your questions at DR.FRGouin@gmail.com. Please include your name and address.

Pet poop and chicken skat don’t fit in

If you’re making compost for your vegetable garden, don’t add manure from pets or backyard hens. There is always the possibility that dog manure may contain hookworms. Chicken manure contains high levels of salmonella organisms. Unless temperatures in your compost pile remain at 150 degrees or higher for five days running, neither of these disease-causing organisms will be killed.
    The standard of 150 degrees or higher for five days was based on research conducted on composting bio-solids from wastewater treatment plants and chicken manure from broiler farms. These standards are called PFRP — Processed Further to Reduce Pathogens.
    Such high composting temperatures cannot be reached or maintained under home composting systems. PFRP requirements can be achieved only when large volumes of organic waste are composting under controlled conditions as in certified commercial composting facilities.
    We’ve given serious consideration to pet waste in efforts to keep it from polluting creeks, rivers and the Bay.
    With laying hens in many backyards, chicken sanitation is an issue needing equal attention. If you were to visit a chicken farm, you would be required to wear rubber boots and walk through a shallow pan of sterilizing solution before entering and exiting the poultry house. The sterilization solution works to prevent diseases from being carried into the poultry house and salmonella from being carried out.  
    Children should not be allowed to play in areas where chickens are foraging, and safe disposal methods for their waste must be devised flock by flock. 
    One way is direct composting chicken waste in flower gardens or in landscaping. In those uses, the only health risk is from handling the manure.


Keeping Silt Out of Pond Waters

Re: Stopping Brown Bay Waters: www.bayweekly.com/node/29154

Q Thanks for your great Aug. 20 article on Stopping Brown Bay Waters. I live on a four-acre tidal pond. Several of the properties have steep slopes, and there are two ravines that cascade heavy rains into the lake.
    Whether we have rain or not, the water is always murky brown. From your article it appears that the Filtrex Sox would help in the wooded ravines. Would it help to line the shoreline with it as well?

–Dave Bastian, via email

A The Filtrex Sox is being used to line the sides of creeks and shores of lakes and ponds. I recently saw it being used in Maine in highway construction.

Ask Dr. Gouin your questions at DR.FRGouin@gmail.com. Please include your name and address.

Nurseries want to sell, and planting time is right

Many garden centers and nurseries have fall sales to reduce their inventory. What doesn’t sell, they have to spend money protecting in winter or suffer losses.
    These sales are timed right for you, too, because early fall is a great time for planting trees, shrubs and perennials, as the plants have time to establish roots in their new soils before winter sets in.
    Plants produce new roots faster when their tops are going dormant. In preparation for winter, most woody plants stop growing leaves and new shoots starting in mid-August when daylight hours grow shorter and evenings become cooler. Thus, all of the sugars being produced by the foliage are directed toward growing new roots. New roots this fall means more top growth next spring.
    Container-grown plants you buy now have been growing in that container all summer. Therefore, it is likely that the outer edge of the root balls are encircled by roots, a good indication that the plants are root-bound.  If you transplant such plants without disturbing the roots, it is unlikely that they will survive the winter because new roots cannot break through the mat into the surrounding soil.  
    When removing plants from their containers, examine the root balls carefully. If the roots have filled the container, pull them loose or slash them with a sharp knife.  I prefer slashing the outer edge of the root ball from the top to the bottom approximately one inch deep at three- or four-inch intervals. By slashing the outer roots, you will be forcing the fine roots to branch and form new roots in the new soil.  
    An alternative method is to crush the root ball until you see the roots loosen, and use your fingers to pull the loosened roots away from the ball. This method requires more time but achieves similar results.
    Never dig the transplant hole any deeper than the depth of the root ball. Ninety percent of the roots of trees and shrubs are in the upper six inches of soil. Plant with 10 percent of the root ball above grade. Back-fill with a mixture of one-third by volume compost blended with two-thirds by volume existing soil.
    The compost will provide not only the essential nutrients for good root growth but also a transition zone for roots that have been growing in a soilless mixture. If you are transplanting azaleas, blueberries and related species, blend one to two tablespoons of gypsum into the soil before backfilling. Acid soils are nearly always deficient in calcium, which is essential for good root growth.


Ask Dr. Gouin your questions at DR.FRGouin@gmail.com. Please include your name and address.

Move crowded azaleas this month

Perhaps you planted young azaleas close together to achieve instant effects. Within a few years, those young azaleas will be crowding each other. Unless you remove some of them, they will grow tall and spindly.
    September is the best time of the year to dig and transplant azaleas, rhododendrons, andromeda, mountain laurel, blueberry and related species. By early September, the plants have stopped growing and are setting flower buds. When plants stop producing stems and leaves, they start producing roots. Thus, transplanting in September gives the plants time to establish themselves and be ready to resume normal growth in the spring when they begin to flower.
    When transplanted in the spring, the plants will flower, but new growth will be limited because the plants have to grow new stems, leaves and roots at the same time.  
     Azaleas and related species are very particular about where they grow. Unless irrigated during drought, they are best grown in light shade. On the other hand, the more direct sun plants receive, the more flowers they produce. Under dense shade, they will produce good dark foliage but few flowers.
    It is always best to grow these  plants in deep organic-rich soils that are acid in nature so they can absorb nitrogen in the ammonium form. Ammonium nitrogen is more readily available in acid soils than in neutral soils such as those good for growing annual flowers and vegetable gardens.
    To avoid problems, have your soil tested before planting. A good soil test will provide the pH of the existing soil, the amount of calcium and magnesium present as well as other essential nutrients essential for good plant growth. Never fertilize these species with lawn fertilizers; they contain nitrogen in the nitrate form, which will cause stunting.
    Acid soils tend to lack calcium, which is essential for good growth. Calcium is as important in plants as it is in humans. Thus, to supply calcium without making the soil neutral or alkaline, blend a few tablespoons of gypsum (calcium sulfate), into the soil before planting. If the soil is low in magnesium, add a tablespoon of Epsom salts, which is magnesium sulfate.
    Successful transplanting also depends on careful watering. A newly transplanted shrub or tree should be watered thoroughly at three-day intervals. Light daily watering does more harm than good.


Ask Dr. Gouin your questions at DR.FRGouin@gmail.com. Please include your name and address.

These sensitive trees show you air pollution in action

If your Heritage birch is dropping yellow leaves, blame it on the Orange Alert of early August. Heritage birch is a clone of river birch, which is highly sensitive to both ozone and sulfur dioxide. Both of these gasses are present in an Orange Alert.
    An Orange Alert is announced to warn the elderly and people with pulmonary disorders to remain indoors in air-conditioning and minimize outdoor activities until the alert is lifted. Heritage birch, the deciduous trees most sensitive to air pollutants, have no choice but to remain in place and try to survive.
    Maple, oak, cherry, apple, dogwood and other tree species are not affected.
    Only older leaves are yellowing and dropping. Younger leaves closer to the ends of the branches are remaining green, and the trees are producing new leaves at the ends of the branches.
    Age is the cause of the leaf drop. The spongy layer of plant cells in leaves converts carbon dioxide into oxygen by absorbing air through small openings called stomata on the underside of birch tree leaves. These stomata are surrounded by guard cells that open and close depending on moisture, time of day and the presence of air pollutants.
    In younger leaves, the guard cells remain very flexible. As soon as they detect air pollutants entering the leaves they close, thus preventing damage to the spongy leaf tissues that absorb carbon dioxide and release oxygen. However, as leaves age, the guard cells become sluggish and sometimes stop functioning, thus allowing the polluted air to enter and kill the spongy leaf tissues. In other words, the guard cells are not as spry as they once were.
    Once the spongy leaf tissues are killed by the air pollutants, the older leaves react as if they had been damaged by an early frost.
    If the air pollution were to occur at night, it is unlikely the problem would be as severe because the guard cells close at about the same time the sun sets. The damage would be limited to only those leaves where the guard cells are stuck in the open position.


Ask Dr. Gouin your questions at DR.FRGouin@gmail.com. Please include your name and address.

Fall gardens want compost

It is highly unlikely your garden has used up all the fertilizer you applied this spring. This is especially true if your garden soil is rich in organic matter and you used lots of compost.
    Compost raises soil temperatures, while its organic matter releases nutrients at a rate nearly equivalent to the needs of plants. The roots from the previous crop are also decomposing and releasing nutrients.
    If you used your own compost or one based on yard debris, your plants will benefit from an application of nitrogen. But if you used compost from lobster waste or crab waste, you’ve almost certainly got all the nitrogen your fall crops will need.
    If you are an organic gardener, blood meal, cottonseed meal and fish emulsion are good sources of nitrogen. Other sources of nitrogen include calcium nitrate, ammonium sulfate, ammonium nitrate and urea. Don’t apply slow-release formulas on fall vegetable gardens.
    Fall gardening is an excellent time to maximize your use of compost. If you are tilling the soil to control weeds, incorporate compost into that surface layer of soil. With soil temperatures into the upper 70s, the compost will instantly start releasing nutrients at just the correct rate to promote good steady growth of plants. As the soil begins to cool in mid-September, the release rate of nutrients from the compost will decrease. At the same time, the nutrient requirements of maturing plants will be less. After soil temperatures drop into the 30s, the compost will stop releasing nutrients, thus reducing nutrients lost to leaching. As soon as soil warms in the spring, the organic matter in the compost will start releasing nutrients.
    Another advantage of applying compost in the fall is that spring garden tilling will incorporate the residual compost more deeply into the soil, where it will help reduce the bulk density of the soil and improve its structure.
    Organic matter does so much good for soils. In addition to providing nutrients and reducing the density of soil, compost also has disease suppression properties most effective when applied in late summer. Soil-borne diseases are most prevalent when soil temperatures are high. Applying compost to your garden soil in time for planting the fall crop helps maximize all of the benefits compost has to offer.
    Only where you’re planting carrots do you want to skip the compost. Carrots grown in composted soil will look like clusters of fingers. That’s because high levels of organic matter tend to cause multiple roots to develop on tap-rooted plants. I reported these findings from studies I conducted in the mid 1970s on the use of compost in the production of black walnut trees. This effect was beneficial for producing walnut seedlings for transplanting but not good for growing carrots, where a single root is preferred.


Ask Dr. Gouin your questions at DR.FRGouin@gmail.com. Please include your name and address.