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Tuesday, March 20, 2018

March 20, 2018 Kim’s Weekly Garden Blog


Hi Gardeners

It’s officially spring!  It’s a sunny day here but quite chilly-36 degrees-with a good breeze too.  A great deal of the snow has melted, and my still blooming snowdrops have emerged fresh and pretty.  There are green leaf tips on the honeysuckle plants. The red nubs of rhubarb are pushing through the ground.  The birds have been singing like crazy and Sunday when the temp got up to 50 I heard a couple frogs, spring peepers, slow and sporadic, but singing.  My remaining tree frog in the houseplants has been calling too.

The turkey vultures and killdeer are back also.  When I see the turkey vultures I know spring is here.  They have a lot of dead deer to clean up along the roads.  That’s one bird that won’t go hungry waiting for warmer weather.  I am seeing flocks of whistling swans and sandhill cranes flying over going north.

Next week I will start the first seeds for spring planting inside.  I have begun watering the stored bulbs in their pots on the porch and fertilizing the houseplants.  Things are beginning to grow as the sun warms the soil and the day lengthens.

As I hear of another school shooting and another package bomb today I just keep thinking about the sun shining and the birds singing and how nature heals. If you are depressed from all the bad news get outside and soak up some sun, even if you do it with your coat on.

Looking for houseplants in all the wrong places

The new fad in houseplants is a plant called the Chinese money plant.  It’s a plain green, small plant whose distinguishing feature is round leaves.  However, people are willing to pay $50 or more for small pots of the plant.  It doesn’t grow well from seed or cuttings, I guess division must be the means of propagation and that figures into the price.  It doesn’t excite me, but to each their own.

Many of our tropical houseplants are weeds or at least extremely common plants in the areas they are native to. (And there are people who come to the US and marvel at our roadside plants and field weeds.) Do we have any weeds here that might make good houseplants?  How do we decide which plants to choose for houseplants and are we overlooking plants that might make great houseplants?

Old fashioned geranium
We might start looking for good houseplants by simply remembering what our grandparents grew as houseplants.  I remember going to an old feed store as a child and seeing zonal geraniums (pelargoniums) in the south picture window that were 6 feet tall and blazing with red flowers all winter.  I have a wide range of geraniums in pots on my unheated Michigan porch and most bloom all winter. 


My grandmother had a collection of scented geraniums, the bruised leaves smelled like chocolate, lime, roses, cinnamon and numerous other things.  They were the hot thing back then with hundreds of cultivars to choose from.  Now you rarely see them offered and they would make such wonderful houseplants. If you don’t like flowering houseplants, these scented geraniums often have interesting variegated foliage and you could keep the small flowers cut off.

One could go to the nursery this spring and buy a wide variety of small potted geraniums, all colors, sprawling ivy types for baskets and large and small uprights, some with interesting variegated foliage as well as pretty flowers and many would cost a $1 a pot or just a bit more.  Instead of tossing them in the compost pile at the end of summer bring them inside for houseplants. 

Gerbera, sold in almost every nursery and many grocery stores, is actually a perennial and people used to keep them as houseplants.  (See the article on gerbera this week.)  They are a little fussy as a houseplant but not more so than African violets.  They are inexpensive too and will flower all year around in a variety of colors.

Other plants that were once used as houseplants include abutilon, small flowered fuchsia, wax begonias, Eucharis, Felicia, Glechoma, Heliotrope, Iresine, Kohleria, Manettia, ( fire cracker plant), Myrtus, Passionfruit (Passiflora caerulea), Plumbago, Chinese primrose (Primula sinensis), Rhoeo ( Moses in the cradle), Strelitzia ( bird of paradise), some sedums, Sempervivium arachnoideum ( cobweb houseleek ), and Viburnum tinus.  These may be harder to find now but still make good houseplants.

What about our weeds?

I’m wondering if we shouldn’t look to some of our common weeds as houseplants.  A good houseplant should be evergreen, and not have to drop it’s leaves and go through a cold period to be healthy.  It should be able to grow in most homes humidity and heat conditions.  It should have a pleasing shape or interesting leaf pattern and flowers would be plus.  And of course, it should be a perennial.

If you go outside here in zone 5-6 in the early spring, you’ll see some plants remained green under the snow and don’t need much light or heat to begin growing again.  I’m sure higher planting zones have even more plants like this.  Could some of them become good houseplants?  Maybe great houseplants with a little selective breeding?

I brought a small pot of rex begonia (also an older type of houseplant) I propagated this summer on the deck, inside this winter. I put it in the laundry room window which faces east.  Some ground ivy popped up in the pot. Ground Ivy, (Glechoma hederacea) is a common weed across the northern US and it does stay green under the snow. The ground ivy has cascaded down the side of the pot and is growing nicely.  It’s looked as nice as many other types of ivy grown indoors all winter. 
Rex begonia with ground ivy.

And I suspect the ground ivy will bloom this spring, it has pretty purple flowers.  Ground ivy roots easily at the nodes so propagation would be easy.  I can see a nice hanging basket full of ground ivy.  It might have to be given a cute name- maybe Gill over the Ground, or Creeping Charlie, common names it already has.

There are cultivated Lamiums that we use for ground covers that were developed from spotted deadnettle, a perennial weed.  Many of these have variegated leaves and pretty flowers in the spring.  How many of these would make nice houseplants?

Slender speedwell, (Veronica filiformis) is a perennial weed similar to ground ivy but with smaller leaves.  In early summer it is covered with tiny pale blue flowers with a darker blue stripe.  It was actually introduced here as an ornamental and I think it might make an excellent hanging basket plant.

Moneywort, (Lysimachia nummularia) might be our answer to Chinese dollar plants.  Its a vining plant with glossy round leaves and there are some ornamental varieties sold as groundcovers. Moneywort has pretty yellow flowers. Some cultivated varieties have golden foliage.  I have this is in my lawn and may try a pot to see how it does inside next winter.

I am going to try some pots of common native violets (Viola papilionacea) inside next winter.  I believe they would grow and possibly bloom.  There are different colors of these too. The flowers aren’t scented like English violets (Viola odorata) but still pretty.

While not considered weeds, there are many types of small sedums that are evergreen.  New ones are always coming on the market.  They may make excellent houseplants.  And my grandmother kept hens and chicks, (Sempervivum species) in the house.  Indeed, these used to be called houseleeks.  You’ll find a wide variety of colors now in garden shops and they make good, easy care houseplants.
Sedum Tokyo Sun might make a good houseplant , the vine in this picture
is Illumination periwinkle- which might also be a houseplant candidate.

And when you are looking for houseplants you may want to check places like bulb/ bareroot catalogs instead of pricy houseplant suppliers.  For example the black bat flower (Tacca chantrieri) was offered in McClure and Zimmerman’s bulb catalog for $12.95, which is half what I saw it listed for in houseplant catalogs.  Various species of oxalis often used as houseplants are grown from bulbs or tubers and these are very inexpensive in bulb catalogs compared to buying a potted plant.

Species of ginger grown for houseplants are inexpensive when you buy them as rhizomes in bulb catalogs.  You can also find ground orchids, Eucharis, and several other interesting bulbs and rhizomes that can be grown indoors when you take the time to explore catalogs and websites.

So, if you aren’t looking for houseplants in your yard, along the roadside, in the local garden shop and in bulb and bareroot catalogs maybe you are looking for houseplants in all the wrong places.

Gerbera daisies

My mother has a fondness for giving gerbera daisies as gift plants. I don’t know if the large colorful flowers stand out to someone who is nearly blind, or she just likes their cheerfulness and inexpensive cost. I used to be rather indifferent to their charm, I considered them to be an annual flower that was hard to work into my planting schemes.  But I have grown to appreciate them and now that I know they can be overwintered and return for a second or third year and make good houseplants, I even buy them myself.

The gerbera daisy (Gerbera hybrida), has been in cultivation a long time now but until the last 30 years or so it’s full potential really wasn’t realized.  Gerbera daisies in cultivation are a mixture of several species from the southern hemisphere, South America, South Africa and Southern Asia. Thanks to the breeding work of growers in the Netherlands, Columbia and California gerbera daisies now come in a wide range of colors and forms.

Gerbera daisies are the fifth most popular cut flower, with millions being sold each year across the world.  They hold up in a vase for a long time and are sturdy enough to ship well.  They are also popular as potted gift plants and as plants utilized in container plantings and even in flower beds.  Gerbera daisies can also be kept as flowering houseplants.

Gerbera daisies are also referred to as Transvaal daisies or African daisies in some places.  Since they are a major floral crop, there is a ton of cultural data out there, how to manipulate light, heat, fertilizer and so on to extend or delay flowering, control stem length and various other factors.  But this article will focus on what care the average home gardener needs to give them.  

The gerbera daisy has a crown type plant structure, with all the leaves originating near the base.  Plants vary in size with the average mature plant about a foot high and wide.  There are mini-plants and extra-large plants on the market.  The leaves of gerbera are longer than wide and can be 12 inches long.  They have lobes near the base and are rough and often slightly hairy. 

The flowers of gerbera daisies remind one of small sunflowers. They have a row of ray flowers or “petals” around a central cluster of “disk” flowers that are often a contrasting color from the petals.  There are now double, semi-double and crested type flowers on the market. They range from about 3 inches across to more than 6 inches, depending on variety.

Flowers rise from the center of the plant on stems of various lengths.  The longest stems, 6 inches or more, are for varieties used as cut flowers.  These are usually greenhouse grown and impractical for gardeners. Gardeners can choose gerbera with modest stems or plants whose flowers remain quite close to the crown.

Gerbera comes in any flower color imaginable except true blue. There are flowers with several colors, some with dark centers, some with rings around the center, the breeders have produced literally thousands of varieties.  The flowers seem to shine in the light and are attractive to bees and butterflies.  They are not fragrant.

The roots of gerbera daisies get quite large and plants grown in the ground become difficult to transplant.  If you are moving them in and out of the house keep them in pots, even if you sink the pots in the ground.

Culture of gerbera

Gardeners should probably start with small gerbera plants.  There is an almost endless variety of plants on the market and some are only available from tissue culture.  They can be started from seeds, and some seeds are offered to home gardeners, but they take a little experience and extra care to be grown this way.  Large mature plants develop several crowns, and these can be carefully separated to start new plants.

Seed from gerbera is very tiny and it must be kept chilled until just before planting.  Seed must be fresh to germinate well, and it needs a 6-8-week cold treatment at about 40 degrees before planting. Seeds should be planted in sterile potting medium that is light and well drained.  They need bottom heat, air temps between 68-75 degrees and light for germination.  Start seeds about 18 weeks before you want flowers and do not put plants outside until after all danger of frost has passed.  Seedlings are quite susceptible to fungal diseases.

Gerbera are only hardy in zones 8- with protection – and higher.  In other planting zones they must be treated as annuals or moved inside before frost.  They are perennial plants and will live several years.  In the north gerbera do well in full sun if kept moist, or partial shade.  In the south gerbera do best in partial shade, preferably morning sun, afternoon shade.

When you buy a small gerbera plant from a nursery put it in a 6-8-inch-wide pot with some depth – gallon pots are good, and plan to leave it in that pot since gerbera daisies don’t like frequent transplanting.  There must be good drainage and the potting medium should be well draining also.  For those who are planting them in the ground the site must be well drained.

The top of the crown must be at soil level or slightly above it.  Gerbera planted too deep are susceptible to crown rot and do not flower well.  Check every so often to see if the crown remains above ground, as settling and watering may move soil into the crown.  This should be removed.

Gerbera needs acidic soil, pH 5.5-6.5 for good growth.  They are susceptible to micronutrient deficiencies if the pH is high. Peat based potting mixes are usually acidic enough.  Potted plants that yellow and look chlorotic may need an acidic fertilizer.

In good conditions gerbera bloom continually.  They are not highly attuned to day length although they bloom better with 10 or more hours of light.  As a houseplant in winter you may need to use a grow light to get good bloom when days are short.

For good bloom plants need dying blooms removed before they set seed and regular fertilization.  A 15-16-17 or 15-15-18 ratio fertilizer with micronutrients works well. Follow label directions for application.  Slow release fertilizers are good as are liquid fertilizers.  Gerbera leaves burn easily so if liquid fertilizer gets on leaves it should be washed off quickly with clean water.

Gerbera is very susceptible to improper watering practices.  The soil should be soaked, then allowed to dry a bit at the surface before watering again.  However, plants should not be allowed to wilt, nor should they sit in water. Root and crown rot as well as fungal leaf diseases may happen if the soil is too wet or the humidity is high for a long time.  Plants shouldn’t be crowded so that there is good air circulation around them.

Insects that may attack gerbera are leaf miners, (outside) and whitefly and spider mites inside.  Use appropriate pesticides.  Outside gerbera are deer resistant.

Gerbera is not edible.  Leaves and flowers contain coumadin, a blood thinner.  While not terribly dangerous the plant should not be eaten by children and pets.

Growing Shallots

Shallots
Shallots, (Allium cepa var. aggregatum) are not to be confused with scallions.  They are separate onion sub-species with different flavors and growing styles.  You will sometimes see them advertised as potato onions or multiplier onions.  Unlike scallions, shallots form small bulbs or cloves each with its own “papery” skin in a cluster at the bottom of the plant.  The shallot leaf is like an onion leaf, narrow and hollow. 

Shallots originally came from South East Asia where they are still widely used in cooking, but they also became popular in France and the Netherlands as cooking staples.  Different countries favor different bulb colors of shallots from reddish colored to grayish.  Shallots have a sweet, mild onion flavor and most good cooks will tell you that there is a difference in flavor of a dish cooked with shallots or onions. Shallots have more calories than onions and slicing them will make you cry just as much as an onion does.

Shallots may be planted in spring or fall.  They like cool weather and can withstand light frost.  At least 6 hours of sun and fertile, well- drained soil are needed.  Keep them well watered to develop the sweetest taste.  Shallots are ready for harvest when the leaves turn yellow.
 
Shallots are almost always planted as sets, (small bulbs) - which are more expensive than onion sets.  You can however, save sets for next seasons or next year’s planting as shallots store as well as onions in a cool dry place. Plant sets 6-8 inches apart.  Either plant in early spring for early summer harvest or mid- summer for fall harvest.  While some shallots that are left in the ground may over winter and return in the spring it is better to save some sets inside through the winter for spring planting.

Shallot seed is also available.  Seed is generally sown outside where the plants are to be grown in early spring and thinned to about 6 inches apart through the summer until you harvest a single “clove” in the fall.  Some of those cloves could be saved for spring planting.  Each clove or set planted usually will return you 4 or more shallots in a cluster.

Many shallots are sold just by color, such as gray or red shallots.  You can also look for Ambition, Sante, Camelot, or French Red.  Shallots can be found at Gurneys www.gurneys.com or Territorial Seed, www.territorialSeed.com

Shallots are an excellent crop for gardeners who also like to cook, because shallots can be expensive in groceries and hard to find. They would also make a good item for farm market sales.  Why not try some shallots this spring?


Free Master Gardener Lesson Soil science part 2- soil chemistry and nutrients

Soil is composed of molecules, which are two or more atoms (the smallest unit we break matter into) that are connected.  Water, for example is composed of molecules that contain 2 hydrogen atoms and 1 oxygen atom.  Each molecule has an electrical charge, either negative or positive. A molecule with an electric charge is called an ion.  In ions remember that opposites attract, and two similar electric charges repel each other.  Keep reading– this seems boring I know- but you’ll see why it’s important to know soon.  

To help you remember this factoid I’ll tell you a story about what happened in one of the first MG classes I taught.  I had a guest speaker for soil science, an ag educator who worked in our office.  He was eager to teach the subject and a funny guy, but he made a major blunder.  When explaining the opposites attract, the same charge repels aspect of soil chemistry he used a terrible analogy.  He said; “it’s like when a man and a woman meet- attraction- and they go together as a pair, but when two people of the same sex meet they repel each other and can’t pair up”.

Now there was silence in the room after he said that.  People did not laugh but no one spoke up.  But I knew I would get complaints after class and yep, they came. I don’t think the man did this deliberately, he just wasn’t thinking and seemed confused but contrite when I had to tell him about the error in political correctness.  Opposites attract doesn’t apply all the time in all situations.  But by me telling you this story you may remember that in soil ions, opposites attract. So, here’s why that’s important.

Most plant nutrients are ions, and most of the important soil nutrients are positive charged ions which are called cations.  Clay soils and humus are loaded with negative charges. These negatively charged ions attract and hold on to those cations, or positively charged ions of those important soil nutrients.  Both clay soils and soils with lots of humus have on average, higher soil fertility than sandy soils.  That’s an advantage with clay soil gardeners don’t often appreciate.

Nutrient cations are often released when soil ions exchange them for other available cations and those released nutrition cations are taken up by plant roots.  A soil test can estimate how many negatively charged ions are available for exchange.  This is called the CEC value.  Knowing your CEC value can help you decide what soil texture you have and how to manage soil nutrients in your soil. 

A CEC below 5 is a low value, and means you probably have a sandy soil of low fertility.  CEC value between 6 and 10 means you have a loamy textured soil with some humus and moderately fertile. CEC values of 10-20 means the soil has more clay and /or humus and can hold on to more nutrients.  If the CEC is above 20 it probably means the soil is an organic soil like peat or muck soils. 

Plant nutrients

There are 16 essential nutrients for plant growth and development.  They are the macronutrients; nitrogen, phosphorus, potassium, calcium, magnesium, sulfur and the micronutrients; hydrogen, oxygen, iron, carbon, boron, chlorine, manganese, molybdenum, copper and zinc.  Plants need more of the macronutrients, but micronutrients are also important.

Hydrogen and oxygen come from water in the soil, carbon comes from carbon dioxide in the air, but the rest of the nutrients are from the rocks that broke down to form soil.  They are present in varying levels in the soil depending on what rocks were present to form the soil and how much of the nutrient has been lost over time through plant and bacteria use, leaching away and other uses.

I’ll discuss some of the nutrients first and then discuss the use of fertilizers in the garden.

Nitrogen (N)

Nitrogen is used by plants to make root and shoot growth.  Both too much nitrogen and too little nitrogen can pose a problem for plant growth.  Plants vary in how much nitrogen they need but in general too much nitrogen results in tall, spindly growth with little fruit and flower formation. Too little nitrogen results in pale, stunted looking growth sometimes with a reddish or purple tinge.

Nitrogen, one of the most important nutrients, is also the nutrient most likely to be lost from the soil and that will need to be supplemented by gardeners. That’s because it has a negative charge and doesn’t bind to those soil particles that are also negatively charged. Instead nitrogen binds to other soil nutrients like oxygen and hydrogen. Plants absorb nitrogen as nitrate (NO3) and ammonium (NH4+).

Nitrate is sometimes leached through the soil with water and moves out of the reach of plant roots. (When nitrate gets into the ground water that people use as well water it can be a serious health problem.) Ammonium has a positive charge and is less likely to leach through soil. 

Nitrogen is a gas in it’s pure form and can volatize out of the soil into the atmosphere. Ammonium is volatized by bacteria in the soil and the nitrogen released as a gas. Some bacteria form a partnership with plants, living in nodules on the roots of legumes.  These bacteria can take up gaseous nitrogen and transform it into a useable form for plants.

Nitrogen is involved in protein formation in bacteria, plants and animals and when those bodies are living the nitrogen is tied up and unavailable for other organisms to use.  When there are a lot of bacteria breaking down organic matter in the soil they are absorbing the nitrogen from that organic matter and “tying it up” so it’s unavailable for plant use. Eventually though those bacteria die, and the nitrogen becomes available again.

Cold, wet soil may also inhibit the uptake of nitrogen by plants.  There may be plenty in the soil, but the plant can’t use it.  But warmer, drier conditions will restore the plants ability to take up nitrogen and the symptoms of a deficiency disappear.

Since nitrogen can be lost in so many ways the level in soil fluctuates frequently.  Soil tests don’t measure the nitrogen level in soil like they do other nutrients, but the test results will suggest how much nitrogen you should add to the soil based on what crop/plants will be grown there and other characteristics of your soil. 

If gardeners don’t have a soil test to guide their use of nitrogen, you’ll have to use your judgement based on what the needs of the plant you want to grow are- for example both corn and lawn grass need a lot of nitrogen- and also how the plants look as they grow.  Flowering and fruiting plants need nitrogen but too much will result in fewer flowers and fruit and more vegetative growth. Because too much nitrogen can cause human health problems if it gets into water it’s wise to err on the side of too little rather than too much nitrogen.

Phosphorus (P)

Phosphorus is needed by plants for good root growth and in the development of flowers.  It readily binds to soil particles and other elements, in fact it often binds too well and becomes unavailable for plant use. Excess phosphorus can leach away and cause problems though, and gardeners should supplement phosphorus carefully.  A soil test will give you the amount in the soil as well as a recommendation for supplementation if needed. Some states have banned the use of phosphorus in fertilizer to avoid water pollution.

Too much phosphorus may cause other elements needed by plants to become unavailable, notably zinc and iron, which is another reason to use it carefully.  A deficiency of phosphorus causes stunting, changes in foliage color, poor root growth, loss of the lower leaves and poor flowering and fruit development.

Potassium (K)
Potassium is needed for a strong immune system in plants, stress resistance, and stem strength.  It will leach from sandy soils or soils with a very high organic content or if applied in excessive amounts.  It’s one of the three major nutrients often included in fertilizers.

Too much (K) in the soil can cause a deficiency of nitrogen and magnesium and some micronutrients.  Too little (K) in soil causes reduced growth with a shorter space between plant internodes.  The tips of leaves may brown and die. Leaf chlorosis, pale green leaves with darker veins may occur.

Chlorosis in soybean caused by K deficiency

Magnesium (Mg)

Magnesium doesn’t leach from the soil very well and in most soils is rarely deficient.  Most gardeners do not need to apply a source of Mg such as Epsom salts.  In fact, don’t apply any Epsom salt to the garden or potted plants, use a balanced fertilizer if you suspect the plants need magnesium.  Plants need magnesium to produce chlorophyll and for good growth.

An imbalance of magnesium and calcium can be a problem, especially in soil with a high pH. (See soil pH later in this article.) Each inhibits the uptake of the other when the balance is off. That’s why supplying one, like Epsom salts, may cause more problems than it helps.  Too little Mg causes pale, chlorotic foliage, cupped leaves, and results in poor seed production.

Calcium (Ca)

As mentioned above calcium and Mg must be in balance for plants to properly use them.  The balance is affected by other nutrients and soil pH.  Plants need calcium for good terminal growth, like buds and root tips, and sturdy stems and roots.

When plants are deficient in calcium roots may have pits and dead tips, leaves may cup, and stems may be floppy.  New research has found that calcium deficiency does not cause blossom end rot in tomatoes.

Sulfur (S) and micronutrients

Sulfur is easily leached from soil but most soil is not deficient in it, especially in home gardens. Many micronutrients are affected by an excess or deficiency of other macro and micro nutrients in the soil.  It’s rare that gardeners will need to adjust individual micronutrients and too much experimentation with supplements often causes a wide range of problems.

Iron (Fe) is often temporally unavailable when soils are very wet.  It’s also bound up and unavailable when there is high calcium, manganese or phosphorus and when the pH is high.  Some plants are more affected by iron deficiency than others, maples and pin oaks are examples.  Iron deficiency causes pale leaves with darker veins, and sometimes the whitening of young plant tissues.

Boron (B) is used by plants to make seeds and apical buds, too little boron causes poor seed production and break down of plant tissues.  Zinc (Zn) deficiency causes small distorted leaves, short internodes and leaf chlorosis. Copper (Cu) deficiency is more common in soils with a lot of organic matter and causes small distorted leaves and plant wilting. 

Manganese (Mn) deficiency often leaves brown spots on leaves and /or leaf chlorosis with darker veins. Molybdenum (Mo) deficiency produces distorted leaves also, often with a “tail”.  Chlorine (Cl) deficiency causes leaves to wilt and/or turn bronze, then yellow and eventually brown.  It also causes clubbing of the roots. People often worry about watering plants with city water that has chlorine in it.  Some plants are more sensitive to an excess of chlorine than others.  In potted plants excess chlorine causes a salt burn or desiccation of roots and foliage.

Using fertilizer

Different types of plants use soil nutrients in different amounts.   When the same plants grow in the same spot for a long time the elements they need may become depleted, which leads to poor plant growth.  While nitrogen may be returned to soil from the air and decomposition of organic matter some other soil elements are not replenished naturally. 

Chances are good that vegetable gardens and plantings of annual flowers need fertilization.  These plants use soil elements up quickly and because they grow rapidly need fertilization. Roses generally need fertilization.  Lawns may need some fertilization, especially in fall to promote good root growth.  Fruit trees and things like strawberries and grapes generally need some fertilization to perform at their best.

Some plants do better without extra fertilization, they are generally plants that evolved in places with poor soil and are very efficient in using what is available. Some perennials and herbs fall into this category.  When given fertilizer they may grow differently than expected and are more prone to disease. Other plants may have a high requirement for certain elements, called trace elements for good growth.
  
It’s important to know the species of plants you grow as perennials, trees and shrubs in the landscape and what their needs are for fertilization.  Most references will give guidelines for fertilizing common plants.  Some plants like acidic conditions such as blueberries, azaleas and holly.  Using an acidic type of fertilizer helps them grow.  When a plant is said to be a “heavy feeder” it generally will need extra fertilization.

Too much fertilizer is bad for the plants and bad for the environment. You can always give plants more fertilizer but if you over fertilize plants you may burn the roots, cause leggy, weak growth, and more pest problems.  Having a soil test done every few years will let you know what elements may be needed in your soil.  Plants that are growing well, especially things like trees and shrubs, may not need fertilization every year.

Types of Fertilizers

All fertilizer bags are required by law to have several things on the bag.  They must have three numbers on the bag or container.  These numbers signify how many pounds of the major elements plants need, nitrogen, phosphorus and potash (which converts to potassium), in that order, are in the bag.  Nitrogen is first because it is the most important element for plant growth.  Phosphorus in fertilizer is banned in some states such as Michigan because it pollutes water so that place will be represented by a 0.

The three numbers on the bag are based on 100 pounds of fertilizer.  A bag marked 15-20-15 would have 15 pounds of nitrogen, 20 pounds of phosphorus and 15 pounds of potassium per 100 pounds of fertilizer.  If the bag was a 50-pound bag then you would have about seven and a half pounds of nitrogen, (and half the other minerals), in that bag.  The rest of the weight would be made up of fillers, micronutrients, pesticides or other things.

Fertilizer bags also must have a list of active ingredients, the weight of the bag and instructions for proper use.  If there are pesticides in the fertilizer, such as a weed killer, the pesticide name and the pesticide registration number must also be on the bag.  All the ingredients can be compressed into pellets that have all the elements in each pellet or separate pellets or powders containing one ingredient each can be loosely blended in the bag.

It is possible to buy fertilizer ingredients like phosphorus separately at farm supply stores, but they are sold in large bags that would take home gardeners many years to use.  Buy only the amount of fertilizer you can use in one year.  Only buy and use phosphorus if a soil test indicates your soil is deficient in it.

Most fertilizers are made of inorganic/synthetic ingredients.  The plants use these ingredients just as they do the elements found in soil and they don’t care how the nitrogen or other nutrients got there.  It’s no different than you taking a vitamin pill instead of consuming foods with the vitamins and minerals you need.  

Most modern fertilizers release elements slowly, over a long period of time.  Slow release fertilizers are less likely to burn plants but try to keep them off leaves and apply only as directed. Some fertilizers are still quick release, which means the nutrients are all available at once.  This means a quick green up but less margin for error in applying before the plants are chemically burnt.  They must be applied more frequently than slow release fertilizers. 

Liquid fertilizers also give plants nutrients immediately.   Liquid fertilizers must be mixed and applied frequently.  Liquid fertilizers are good for container plants but difficult to use on large gardens and lawns.

There are fertilizers formulated for certain plants, such as tomatoes or roses.  These contain the major ingredients found in all fertilizers and certain trace elements those plants are known to need.  If you have problems with a certain type of plant these may help. Most fertilizers are also labeled garden fertilizer, lawn fertilizer, flower fertilizer etc.  These have different ratios of the major ingredients.  These are the easiest fertilizers for gardeners to use.

Organic fertilizers are things like bone meal, blood meal, and manure that have carbon in them.  They were once alive like kelp or bone meal or they come from living things, like manure and urea.  Organic fertilizers sold in stores should have the same labels as other fertilizers. Most are high in one nutrient only and you may need to buy a combination of things.  New organic fertilizers with more balanced ingredients are also on the market. 

Manure and compost

Some people also fertilize with fresh manure or compost.  Both are great for adding organic matter to the soil but used as a fertilizer they have drawbacks.  Manure and compost vary greatly in nutrient content from batch to batch. You need a great volume of manure or compost, six or more inches, to equal a sprinkling of slow release fertilizer.  Fresh manure can burn plants and it can be the source of food borne illness if used on food plants.  Manure may also bring weed seeds to the garden and is hard to spread on lawns.

Should you buy the fancy mixtures of micronutrients that are popping up in garden stores? Most experts think they don’t make any difference unless you are growing in a soilless mix or hydroponically and are a waste of money.

The fertilizers that home owners use, both synthetic and organic, are a major source of water pollution.  Don’t get fertilizer on hard surfaces like sidewalks where it washes off into storm drains.  Always follow label directions for the amount and way to apply the fertilizer.  Don’t store manure where rain falling on it can run off, carrying nutrients, into drains, ditches and natural bodies of water.

Lime is not considered a fertilizer, even though it may contain some calcium, rather it is used to correct soil pH.  See the section about soil pH next. Don’t add lime to your soil unless a soil test confirms you have very acidic soil. 

Soil pH

The term pH stands for the potential or percentage of Hydrogen ions in a solution.  (The correct way to write this term is lower case p, upper case H.)  In soil, the hydrogen ions are in the water that fills the pores between soil particles. The more hydrogen ions in a solution the more acidic it is.  

Hydrogen gets into soil from the rocks, from the breakdown of organic matter and from chemical reactions in plant root systems. The more hydrogen in soil the more acidic it gets.  Different minerals in the soil dissolve and become available to plants at different levels of pH.


A pH scale is a way to rate how acidic or alkaline soil is.  It ranges from 0-14.  Seven is considered neutral. Above 7 is alkaline and below 7 is acidic.  The pH increases or decreases by ten times for each point on the scale.  A pH of 6 is ten times more acidic than 7 and a pH of 5 is ten times that or one hundred times more acidic than a pH of seven.

So what does pH mean to gardeners?

How acidic or alkaline the water in soil is determines what kinds of mineral elements get dissolved and become available to plants or get bound up in complex reactions and become unavailable.  Most plants grow best at pH levels of 6.5 to 7.5.   That is where the most beneficial minerals become available to them.  A few plants have adapted to survive in pH levels slightly higher or lower than that.

In addition, the pH level in soil also affects the microbes and micro-organisms that break down organic matter that adds nutrients to soil.  They like to grow at about the same pH level that plants do.

The soil your plants are in can have all the essential elements needed for producing food but if they are unavailable because of too high or too low pH the plants can’t use them and will suffer.  Certain plants are more sensitive to the loss of certain minerals such as iron.  When the pH of soil goes above 6.5, iron becomes largely unavailable to plants. Some plants like Pin oaks will quickly decline.  In other cases, the pH level may cause toxic elements, such as aluminum, to become too available to plants

Many plants are not terribly fussy about soil pH, but your soil pH may determine whether some species will survive in your garden.  But just because plants will continue to survive doesn’t always mean all is well.  Marginal deficiencies caused by pH problems may cause your plants to become more susceptible to disease and insect attack because their immune systems aren’t as effective.

Pesticides may not work effectively if your soil pH is too high or low either.  They are developed for use in the pH range that most plants prefer.  The chemicals in them may react with elements available in too high or low pH conditions.
Soil nutrients available at different soil pH levels.

How do I find out my soil pH?

You can get your soil tested at almost any County Extension office in the United States.  Many garden and farm service stores also offer the service.  They will tell you how they want you to collect and submit the specimen.  These places will generally give you recommendations with the results for fertilizing or changing the soil pH.

There are small kits that have you mix water and soil and test the pH but these are not very reliable.  If you are a person who likes to do it yourself, you can purchase a small meter that has probes that go into moist soil and reads the pH.  The more expensive ones used by professional growers are pretty accurate.

How do I change my soil pH?

Soil pH can be raised much more easily than lowered. If your results are only slightly out of optimum range and your plants seem to be growing well don’t worry too much.  Adding lots of organic matter and working it into the soil will help balance soil pH.  Lime can be added to soil that is too acidic to raise the pH. This works fairly quickly.  Don’t add lime until you know your soil needs it and then follow the recommendations for your situation.  Soil may be acidic if it is too wet from poor drainage or lacking air from soil compaction.   Changing these conditions may help.

Lowering soil pH is harder and takes longer than raising it.  Too much lime or too many wood ashes can raise soil pH as can natural conditions.   Adding organic matter helps.  Fertilizers such as ammonium nitrate or ammonium sulfate will tend to lower pH.  These are often marketed as fertilizers for acid loving plants. If the drainage is good lots of rainwater may leach out some of the alkaline elements over time.

For small areas aluminum sulfate or sulfur can be tried.  You will need to consult with your county Extension office or other garden expert to find out how much to use on your soil.  This method will be quite expensive.

Choosing plants that like the soil pH you have in your yard is another good way to minimize plant stress, providing the soil pH is not too high or low.  There are plants that like both more acidic and more alkaline conditions.

This is a long article and I think most of the soil science lesson is completed.  Next week’s lesson will be on composting and will probably be shorter.  For a homework assignment get a soil test done for your garden or find out your soil pH.

Chocolate -peanut butter cake

This is a quick dessert that my husband loves.  I made it this weekend.  I make these in small pie tins, like pot pie tins, which will serve two people.  The recipe will make 5-6 cakes this size and you can freeze some.  You could also make this as large cupcakes, or I suppose as a bundt type cake.

Ingredients

1 chocolate cake mix – I like chocolate fudge flavor mixes
½ cup melted butter- 1 stick
3 eggs
1 ¼  cup water
1 pkg. (8 oz.) cream cheese
1 ½ cup creamy peanut butter
½ cup cream (or milk)
½ cup powdered sugar

Directions

Spray cake pans with pan spray and pre-heat oven to 350 degrees.

Blend together the cream cheese, peanut butter, cream and powdered sugar until well mixed.  It will be thick.  Set aside.

Mix together cake mix, water, eggs and butter.  Beat about two minutes with mixer on high speed.

Pour about 2 tablespoons- (I use a gravy ladle), of the cake mix in each pan.

Add about the same amount of the peanut butter mix to each pan. There will be some of the mix left over, refrigerate for later.

Divide the remaining cake mix among the pans.  Make sure to cover the peanut butter mix.

Bake about 15-20 minutes for the small pie tin size.  A knife inserted should come out clean.

Let cakes cool and then frost with the remaining peanut butter mixture. 

Get your face in the sun and your spirits up.
Kim Willis
 “He who has a garden and a library wants for nothing” ― Cicero

© Kim Willis - no parts of this newsletter may be used without permission.

And So On….

Find Michigan garden events/classes here:
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