Tuesday, March 13, 2018

March 13, 2018 Kim’s Weekly Garden Blog

Hi Gardeners
Tulip slyvestris
Since I wrote last the ground was covered in about 8 inches of snow.  A little has melted, although it’s not that warm.  The trees are coming out of dormancy and they are producing enough heat that snow is melting around their bases leaving spots of bare ground.  That’s probably what keeps the robin that’s singing each morning going. But the flowers are buried.

When I walk to the barn each morning- or rather wade- since I am not shoveling anymore- I hear the birds singing like crazy.  It’s 7 days until calendar spring and I hope the weather will improve to match it. Our weather is not as bad as some of you have on the northeast coast and in a few other places.  I try to be thankful for that.  If you are one of the snow buried I feel for you.  It’s snowing pretty good as I write this, but the next few days are supposed to be snow free and milder.

Don’t worry about flowers that came up and got snow buried.  Unless they were just about to open their blooms, they will be fine.  Even if the blooms got damaged the plants should survive. Snow will actually insulate the plants. Most perennials that may have started growing will just suffer some cold damaged foliage and won’t be permanently injured.

If you had branches cracked or broken by heavy snow and winds, make sure to trim them off evenly close to the branch collar.  You do not need pruning paint.  If evergreens and shrubs were bent and bowed by snow let it melt to see if they spring back into shape.  If they don’t you may have to gently tie them together or stake them temporarily.  Be very careful you don’t crack branches moving them, it would be better to leave them if that’s likely.  Remove ties and stakes in a few weeks.

If you are anxious to see some spring blooms you can cut and force some early flowering plants to bloom inside.  Pussy willows, forsythia, fruit trees, flowering quince, and redbuds that have big flower buds can have branches cut and placed in a vase of water inside.  They should bloom quickly this time of year.
Have you fertilized your houseplants yet?  It’s time to start, especially if you have patio type plants you want in bloom when the weather warms up.
Let’s all hope for better weather next week.

Why does soil (or potting medium) disappear from flower pots?
Have you ever looked at a pot and realized that the plant had sunk into it by several inches, as if something had removed planting medium from the bottom?  Most people who raise plants in containers, whether as houseplants or in outdoor planters have experienced this.  So where does the potting medium go?

Well it doesn’t get absorbed or “used up” by the plant, which is something many people think.  Plant roots don’t absorb potting medium or soil.  In some cases, some potting medium may wash out through the drainage holes, this is more likely if the pot is outside and subjected to heavy rains.  However, the correct answer most of the time is that the organic matter in the pot has decomposed, broken down, into smaller particles.

Potting medium generally doesn’t contain any real soil, it’s a mixture of organic and man-made ingredients like ground bark, coir, peat, vermiculite and perlite.  Even inside the home the organic ingredients begin to be broken down by microorganisms and over time they are reduced to smaller and smaller particles.  These particles settle, and some may even dissolve in water.  Even if you filled your pots with garden soil the organic matter in the soil will eventually break down.

Think of the process as a mini- compost pile.  You start with a huge pile of leaves, weeds, manure and other things but when the pile is ready to be used it has been greatly reduced in volume.  Or think of filling a pot with coarse chunks of wood chips.  Then take those wood chips and run them through a grinder until they are the consistency of potting medium.  Now they won’t fill the pot even though they filled it earlier. The potting medium you fill your pots with has small particles of organic materials, but they break down into even smaller particles over time. 

If the plant is vigorously growing and has filled the pot with roots the break down of the potting medium may not be obvious.  What will be obvious though is that when you water the pot, water seems to flow right through it and the plant needs watering frequently to keep it alive.  That’s because there is very little organic medium left to absorb water.  Water is held in the pores of the potting medium and the smaller the particles of organic matter, the smaller the spaces or pores between them. 

So, what do you do when you gaze into a pot and discover it has half the volume it once had?  You can simply slide the plant the plant out of the pot and add some fresh potting medium to the bottom.  You may have to fill in some along the sides also.  You want the top of the original root ball to sit about an inch below the pot rim.  Don’t add soil to the top of the pot.  You don’t want the stems of the plants any deeper in the potting medium than they were before.

If the pot does seem to be losing potting medium or soil through the drainage holes, because you can see where it has washed out, slide the plant rootball out of the pot and add a paper coffee filter or a piece of screen to the bottom.  Then add some new potting medium as described above.

If the pot still seems full but is having trouble absorbing water, you can re-pot it in a slightly larger pot with fresh potting medium.  Roots that circled around and formed a thick mass at the bottom of the pot can be trimmed straight across an inch or so from the bottom of the root ball and the roots teased apart slightly.  If the plant has multiple crowns or there are several plants in the pot you may want to divide the plants and make a few smaller pots.

Sometimes pots that seem to be shedding water instead of absorbing it are simply over dry and the medium has shrunk away from the sides of the pot, leaving an easy channel for water to flow through.  Try soaking the pot in a bucket of water for an hour or two, the water should come to just over the top of the pot.  It may float if its very dry, hold it down in the water and let air bubbles escape until it settles into the water.  Take it out after the potting medium is thoroughly soaked and don’t let it get that dry again.

When you have large planters or raised beds outside, adding organic matter to the top of the bed when plants aren’t in it can correct the problem. You can dig it into the top layer of soil or potting medium or just let it decompose on top.  Don’t add a lot of new organic matter or potting medium to the top of planters while plants are growing in them.  Very large planters can be difficult to slide plants out of to add potting medium to the bottom. You may have to take the plants out and add new potting medium to the top, and then re-plant the plants.

Potting medium that has broken down to very fine particles doesn’t hold water well and may be more prone to crusting or hardening. You may want to discard it and use new potting medium. Because plant roots usually need the depth of the pot for good growth and potting medium is needed to balance the weight of the plant top growth, correct shrinking soil medium as soon as you notice it. 

More seed starting tips

These tips are more “garden-granny” type than last weeks tips. 
Every inside seed starter should have these tools in their “kit”, a pair of tweezers, a small pair of scissors, a nail file or nail clipper, a spoon or spork- plastic is fine, a pencil with an eraser, a small ruler, a marking pen.

The tweezers will help thin or transplant seedlings.  The scissors will cut out seedlings you need to thin out and are useful for other things.  The nail file or clippers are for nicking hard seeds so water can enter and begin the germination process.  I like to use a nail clipper to pinch out a piece of seed shell on one end of the seed. Don’t nick the curved side of the seed, the side with the scar.  This is where the plant embryo will be.

A spoon works well as a tiny spade for transplanting seedlings.  A spork, one of those spoon/fork combo’s works really well when transplanting. If you moisten the pencils eraser you can pick up small seeds that fingers have difficulty handling and place them where you want them.  With really fine seeds a moistened toothpick may also work. The ruler let’s you actually measure how far apart seeds are and the marker lets you label what you planted- because you will forget.

If you are trying to transplant and not thin, always move the plant by it’s leaves, not the stem.  If you break a leaf it’s fine, one will grow back.  If you damage the stem you’ve probably killed the seedling.

Save these things to make plant labels: popsicle/craft sticks (wash used ones with hot soapy water) plastic window blinds (cut the blind slats in pieces with scissors) plastic table wear- the handles can be written on or the knife blade or spoon bowl, and paint stirring sticks.

Save these things to start seeds in; deli containers with clear dome lids, cake and baking pans with clear lids, cheap aluminum roasting pans (for trays and mixing potting medium), Styrofoam cups.  Wash all used things with hot water and soap before using for seeds.

Do you have trouble spacing seeds because they are hard to see against the starting medium or soil?  Get a bag of white sand or parakeet gravel.  Make your furrow, put a little sand or parakeet gravel on the bottom and place your seeds.  Cover with starting medium.  Do not use flour or other food items.  They will mold and attract animals.

Outside when planting seeds and you need to mark where different varieties start or where your planted rows are, you can use the sand or gravel in a thin line or even a little sawdust or wood shavings to mark or outline areas.  You can also mark rows with sturdy sticks that you have dipped or sprayed with colorful paint.

If you have trouble stooping to evenly space seeds use a piece of PVC pipe cut to just the right height for you.  Place one end where you want the seed to go and drop the seed in the other end while you are standing- or sitting.

A bag of cheap wood skewers can make supports for small plants.  If you place them pointed sides up and circle your seedlings they can protect them.  Plastic forks with the tines up can also protect seedlings.

Save cardboard toilet paper/paper towel tubes and cut them in sections.  Use the sections around seedling plants outside to protect plants from cutworms.  You can also set these sections in a tray, fill them with seed starting medium and use them to start seeds like peat pots.  I do this and find it works well, the cardboard peels off easily when you transplant the seedlings.

Should you grow castor beans?

The castor bean plant (Ricinus communis) makes a commanding and exotic statement in the garden.  Gardeners are often attracted to a stately, gorgeously colored plant and want one of their own, until they are told how poisonous the plant is.  So, let’s address this issue first- how dangerous is the castor bean plant?  The answer is- pretty dangerous, but that doesn’t mean you can’t grow it.

Many common garden plants are poisonous, many gardeners have no idea how many potentially deadly plants they have in the garden. Here’s an article that will help you determine what poisonous plants you have.

Castor beans, however, are the source of ricin, one of the world’s deadliest poisons.  Ricin is a chemical weapon used by many country’s and has been used to commit murder or suicide through the centuries.  All parts of the castor bean plant are at least mildly poisonous, but ricin comes from the plant’s seeds.  The beans are also the source of castor oil, a potent laxative that’s also used as an engine lubricant, in brake fluid, as biofuel and in cosmetics.

Castor bean seeds have a thick, hard coating and if someone swallows them whole they usually pass through the digestive system intact, without causing major problems.  However, if the seeds are chewed or ground up, serious illness and death can result.  The poison ricin uses isolated, concentrated chemicals from the seed and may be made into a gas, powder, or liquid injectable, which is extremely dangerous.

The suggested fatal dose of chewed whole castor beans is 8 beans for adults and 2 for children. (Concentrated ricin can kill with just a few small table salt sized grains) There is no current safe antidote for ricin poisoning, but fatalities rarely occur now from ingestion of beans because of modern medical treatments such as stomach pumping, intravenous fluids, respiratory support, seizure medications and other supportive care. But while it may not kill you poisoning from bean ingestion may leave people with organ or brain damage.

Castor plants produce their seeds in the fall. Seed production can be abundant in the right weather. The seeds are very attractive, although they remind some people of an engorged tick and that’s where part of their scientific name comes from.  They are bean sized, black, brown or burgundy, with white or dark markings.  They have been used as jewelry, but this would inadvisable around children and pets.

So, the decision a gardener needs to make before planting this tropical looking beauty is whether they have children, pets, livestock, or vulnerable adults who might ingest seeds if they came upon them and if so, are they willing to risk planting castor beans?  If tight security is maintained on the seeds before planting and flowers are trimmed off before they make seeds the danger is greatly lessened. Pets and livestock shouldn’t be able to eat the plant foliage either.  Gardeners should know however, that some people also have a serious allergic reaction to handling the plants or seeds.

If you think growing castor beans is fairly safe in your situation then read on about the plant and it’s growing needs.

Growing castor beans

Castor bean plants are tender perennials, native to Eastern Africa but naturalized in many tropical areas around the world.  In the US they are usually grown as annual plants.  In the wild plants form small trees 30 feet high or more.  In the garden plants may reach 10 feet high in good conditions, so they are best as specimen plants or back of the border.

Castor bean plants have leaves arranged alternately on the stem, on long petioles.  The leaves are palmately compound, (shaped like a hand) with 5 -11 lobes.  Leaf edges are serrated and there’s a prominent mid vein running through each leaf segment.  Some cultivars have narrower leaf segments than the species. The species has green glossy leaves but cultivars (varieties), have been developed with burgundy, purple and variegated foliage.  Leaves can be up to 2 feet long.

The flowers of castor bean appear in late summer on the top of the plant in clusters.  Male and female flowers are separated and neither have petals.  The male flower is a simple cluster of creamy white or yellow stamens, that produce abundant pollen that is carried away by the wind.  It may be allergenic to some people.  The female flower is an unusual and attractive red globe structure, with three segments and feathery appendages.

Fertilized female flowers turn into bristly 3 segmented globes the size of a golf ball.  Each pod segment will contain one seed.  When immature the seed pods are green in the species and red, pink or purple in the various cultivars.  This is the stage at which people may want to remove the seed pods and safely dispose of them. Even immature seeds are poisonous.

 As pods ripen they start to turn brown.  When they split they propel the seed some distance from the plant.  In warmer zones the plants may become invasive if seed pods aren’t removed before they mature.  Castor bean seeds are glossy, in a variety of colors with interesting swirls and streaks of either white or dark colors.  Each seed has a spongy appendage at one end that helps the seed absorb water from the soil for germination.  If you save seeds remember they are very poisonous and store them safely out of the reach of children and pets.

Gardeners can start castor bean plants from seeds or buy plants from some nurseries. Castor beans prefer full sun in moist but well drained soil.  They should not be planted outside until all danger of frost has passed.

In zones 8 and higher castor bean seeds can be planted directly in the ground.  In lower planting zones start castor bean seeds indoors 8-12 weeks before your last expected frost.   Castor bean seeds germinate better if nicked and then soaked in warm water overnight before planting.  Remember- seeds are poisonous.

‘Impala’ is a castor bean variety that is shorter and more compact, about 4 feet tall.  The ‘Carmencita’ series has leaves and flowers in a variety of colors. ‘New Zealand purple’ has narrower leaves in purple shades.  Other cultivars are available.

In the garden castor bean plants grow rapidly in warm weather. Keep them watered in dry weather.  Because they kill insects which feed on them insects aren’t a problem.  Deer and rabbits don’t eat them either.  There are few diseases that bother them.  While moles won’t eat the plants (they don’t eat plants anyway) the idea that planting the castor bean plant around the yard to repel moles is simply an old wives’ tale.  It doesn’t work.

Castor oil
When castor beans are pressed they produce an oil.  The oil has very little ricin in it and modern castor oil is also treated with heat to remove any remaining ricin.  However, no one can say the oil is harmless, as anyone who has been given the oil can testify.  Castor oil is a very efficient laxative that causes strong stomach cramps and explosive diarrhea.  It was used as a tool for torture in earlier times, with people being forced to drink the nasty tasting stuff in large quantity.  Then they were placed in public stocks to be thoroughly humiliated as they faced excruciating cramps and then the inevitable embarrassment of massively soiling themselves.  Some even died, not from embarrassment but from dehydration.

Castor oil is sometimes still prescribed to clean out the bowels before medical tests.  People still buy it as an over the counter laxative, and I’m sure some parents still use it to punish children.  Pregnant women near term use it to try and start labor.  (Pregnant women who don’t want labor to begin should not use the stuff, it’s also listed as an abortifacient).

The oil is also used in a variety of industrial lubricants and was once used as lamp oil.  It’s used in plastics, paints and varnishes.  And some people even use the stuff in cosmetics and various herbal concoctions.  The “cake” left over from pressing seeds is heat treated to remove any remaining ricin and then used as fertilizer and an additive to animal feed.

I don’t recommend experimenting with castor beans, either the seed or the plant.  Ricin is water soluble.  It is not safe to make tea with the seeds or foliage, nor to cook and eat the beans, no matter how they are prepared and no matter what you read on social media.  Herbal preparations with castor bean in them should be avoided.

If reasonable precautions are taken there is no reason why most gardeners shouldn’t grow castor beans for their tropical beauty. 

Shamrock tales

Ah, the legends of St. Patrick’s Day. (March 17).  Many legends abound about the man and the day.  Nobody really knows if St. Patrick used a clover or shamrock to teach about the holy trinity or whether he used shamrocks to drive out snakes or whether he even wore shamrocks on his blue, (yes blue) monks robes as is so often depicted in pictures.  But somehow the shamrock got associated with him and with Ireland in general.  But what exactly is the shamrock?

Here’s how we determined what a true shamrock is. In the late 1800’s a debate raged among botanists in Europe and America over this very important question.  Some believed firmly that shamrocks were wood sorrel or Oxalis and others that they were of the clover or Trifolium family.  Both plants grow well in Ireland. 

A clever botanist by the name of Nathaniel Colgan carried out a survey in 1893 by asking residents of Ireland to send him pressed samples of the plant they considered a shamrock.  The survey found that the Irish overwhelmingly chose a clover, either Trifolium dubium (Lesser or Hops clover) or Trifolium repens (White Clover) although a few wood sorrel leaves arrived also.

Side note: The “lucky” clover leaf with 4 leaflets instead of 3 is a rather common mutation in clovers and it can be inherited.  In fact, there are varieties of white clover that have been developed that will have a high proportion of leaves with 4 or more leaflets. These are grown to make those lucky charms with a real 4 leafed clover inside. There is a purple leaved variety, T. repens 'Purpurascens Quadrifolium' and a green-leaved variety called T. repens 'Quadrifolium'.

But for most people the shamrock they are going to see around St. Patrick’s Day is usually an oxalis. Oxalis are small plants, with a bulbous root.  The leaves have 3-4 leaflets, sometimes heart shaped.  Most oxalis have small, 5 petal flowers that open flat in the spring, although some species have funnel shaped flowers.  Oxalis or wood sorrel species are common throughout most of the world. There are also a few types of oxalis that can be planted outside.  When looking for oxalis to plant look in bulb catalogs.  They may be called wood sorrel, a common name.  The bulbs are quite inexpensive for most species.
Native wood sorrel

An oxalis that was a fad just a year or two ago is the Candy cane oxalis, Oxalis versicolor.  It has those funnel shaped flowers, striped in red and white.  The pictures in catalogs make the plant look impressive, but actually the plants and flowers are very small.  They are hardy from zones 7-9.  It will grow in sun or partial shade and is best seen in a rock garden setting or in a pot.  It should be planted in the fall.

Oca (Oxalis tuberosa) is a South American oxalis that has an edible root somewhat like a small potato and is used in the same way.  Many oxalis plants have leaves that are eaten in various parts of the world.  The plants are referred to as sour grass in many areas.  The sourness comes from oxalic acid, which if you ate it in quantity might harm you but small amounts are safe.  It was used by sailors to prevent scurvy.

Usually oxalis sold around St Patrick’s Day have purple foliage with pink flowers and are Oxalis regnelli cultivars. ‘Iron Cross’ (Oxalis tetraphylla) is a four- leaved oxalis, green with purple cross markings and pink flowers. It’s a good potted plant.  Oxalis vulcanicola- ‘Molten Lava’ has orange foliage with yellow flowers.  Oxalis adenophylla ‘Silver Shamrock’ has silver gray foliage with light pink flowers.  It’s said to be hardy to zone 6.  Oxalis depressa is a good pot plant with 4 leaved foliage and pink flowers with a yellow throat. It’s hardy in zones 5-8. There are other varieties for plant collectors too.

The species used as “shamrocks” are usually tender perennials and won’t survive outside in a cold winter.  Keep them in a bright window and keep them moist but not over watered to the soggy point.  A light fertilization once a month with a fertilizer for flowering plants will keep oxalis blooming for long periods of time, although they will take occasional breaks from blooming.  Well cared for plants will become larger and live for several years. The tender Oxalis can make great container plants outside during the frost-free months.

When temperatures get very hot in the summer, oxalis goes into dormancy and the leaves dry and fall.  People sometimes think the oxalis has died when it goes into dormancy. Let the pot dry out a little and store it until fall brings cooler temperatures.  Water well, give it a little fertilizer and soon it will be blooming again.  We had an oxalis plant in the Extension office that did not go into dormancy for at least two years, maybe because of the air conditioning.

Free Master Gardener Lesson: soil science part 1

When people signed up for the Master Gardener classes I used to teach they often expressed concern over the first two chapters that are covered; plant science and soil science.  They either thought they would be too complex to learn much about or too boring.  Well soil science can be as complex as you like, what I’ll write about here is just an overview.  But soil science shouldn’t be boring because it’s vitally important to the gardener and the plants he or she grows.

Beneath our feet is a whole, complex world that we are just beginning to study.  Its teeming with microorganisms all going about their lives and we haven’t identified a huge percentage of them nor do we know what all of them do or how they function in the soil biome. Soil is the environment these important microorganisms exist in so we need to study what it is and learn how plants are our connection to this other world.

I hear people mocking other people who use the term soil instead of dirt and consider it a sign of garden snobbery.  But there is a difference between the two and you should learn it.  Dirt is something you don’t want, something useless you sweep up and dispose of, something you don’t want to touch.  Soil is something wonderful, that gardeners love to get their hands into, something that’s of great value.  But here’s a more scientific definition of soil:
Soil is a mixture of broken down parent material- or rocks, called mineral solids, organic solids that were once living things, microorganisms, and pore spaces filled with water or air.
Soil does more than nurture and anchor plants, it absorbs and filters water, is a sink or “sponge” for carbon dioxide and it provides the base on which we build our homes and roads.

What minerals a particular area of soil holds depends on the parent rocks that produced it and chemical actions that have taken place in the soil over millions of years. Rock is broken up by weathering, freezing and thawing, grinding from glaciers, pounding waves and wind, and activities of plant roots and animals.  It is turned into soil by mixing with organic materials, further chemical reactions and the activities of microorganisms.

Every area has different soils, varying in texture size and mineral content as well as acidity.  Soil also organizes into layers, called horizons, as most gardeners have seen when they dug a hole. The layers vary in thickness and composition. The most organic matter is found in the upper layers of soil and soil with more organic matter is the most nurturing for plants.  This is often called topsoil, although that’s an imprecise name.

Geologists group soils with similar mineral and structural characteristics and name them. I won’t go into that type of classification here, but I will discuss some other terms and classifications of soil that gardeners are likely to run across.

Soil texture

Soil is made of different size particles.  The smallest particles are called sand. Medium sized particles are called silt and the largest particles are called clay. When someone talks about having clay soil it usually means that their soil has a high percentage of large soil particles.  Usually soil is a mixture of particle sizes but soil ranges from almost pure clay to almost pure silt or sand.  A soil that has almost equal amounts of silt, clay and sand particles is called loam. 

A soil testing lab can tell you what percentage of soil particles your soil has (as well as the percentage of major mineral nutrients). Gardeners should always have at least one soil test done as a baseline and then you will know your soil texture.  Handling your soil can also give you an idea of what type of soil you have.  Soils with a lot of clay feel smooth and if wet will make a firm ball when squeezed.  Soils with a lot of sand particles feel gritty and even when wet fall apart easily after a squeeze.

Gardeners can also do the jar test, take a trowel and dig down about 8 inches and place the whole scoop of soil in a large jar.  Add enough water to cover the soil and shake it up well.  Let the jar sit undisturbed for 24 hours and the soil should settle into layers.  You’ll get a rough idea of the percentage of sand, silt and clay your soil has.  The organic matter should settle at the top and the rest will be your mineral soil layers.

Soils are usually classified by the percentage of particle size using a soil triangle.  For example, you can have sandy loam, silty loam, clay loam, silty clay, sandy clay loam and so on.  See the USDA soil triangle diagram below.

Knowing the texture of your soil is helpful in many ways.  Different plant species evolved to grow better in different textures of soil.  The soil texture helps determine how you manage your garden.  Some soils hold water longer, warm up faster, hold nutrients differently and compact more easily than other soils.

Soil Structure

Besides texture, different soils have different structures.  Microorganisms in soil produce a type of gummy material that sticks the various kinds of soil particles together.  This is called an aggregate. Aggregates have larger pore spaces between them to hold air and water and those pore spaces act a bit differently than the pore spaces between soil particles.  What is ideal is a soil structure that looks like crumbly granola.  Because microorganisms are more active in the upper layers of soil where organic matter is being broken down the soil structure is different there than deeper in the ground in what is called the sub soil.

Changing the soil structure can help overcome problems a gardener may have because of the soil texture they have.  Soils can drain better or hold more water and nutrients or provide a better environment for plant roots if the soil structure is changed.  Adding more organic matter is one of the best ways to improve soil structure.  It may take a few years but even the sandiest or heaviest clay soil can be improved with organic matter.  The best way to do this is to simply place the organic matter on top of the soil and let nature incorporate it.

Some of the best ways to destroy soil structure and make the soil less hospitable for plant growth are compaction or excessive tilling.  Compaction is caused by foot or machine pressure over time.  It breaks up soil aggregates and/or squeezes them together, leading to fewer pore spaces for water and air and bad conditions for plant roots.

It’s not so much damage to the grass plant blade that makes a frequently used path bare but compaction of the soil that keeps its roots from penetrating the soil and using soil nutrients.  When a new house is being built the builders may avoid hitting or cutting trees, but the machinery needed for construction may compact the soil so badly that trees decline and die over the next couple of years.

Soils with more clay are more prone to problems from compaction, but all soil can be affected.  When the soil is wet it’s more prone to compaction so stay out of your garden in the spring until it has dried out a bit.  It’s also not a good idea to use a heavy roller to iron out irregularities from mole hills in the spring, especially if you have clay-based soil and its wet.

Excessive tilling of the soil is also a problem because it breaks up those soil aggregates and it also re-arranges the soil microorganisms, which all have their preferred level to exist at.  Every time you disturb the microorganisms it slows the beneficial work they do. You do not want soil as fine as flour, as some people think.  This will crust on the surface and impede water and air flow. The pores between aggregates disappear and so does the water and air holding capacity of the soil. Tillers also tend to compact the soil just below the blade depth, which also impedes water movement and roots.

Many farmers have moved to no – till management of their fields and gardeners should follow their lead.  You do not need to till the garden each year and never more than once in a season. Soil is healthier if tilling is avoided.

Soil structure can be changed but soil texture can’t be changed.  As mentioned above there are ways to change soil structure.  But you cannot change the texture of soil in any meaningful way by adding sand to clay for example. It sounds like it would work, but in practice it doesn’t. When you add sand to clay the clay particles fill the pores in the sand, creating a really dense soil-like concrete.  Nature can mix soil particles over millions of years by chemical actions and soil microorganisms but in the short term of garden time spans it isn’t practical nor effective.  If you are unhappy with the soil, try adding organic matter to change its structure.

Soil organic matter

Organic matter in soil is found in two forms. Any once living thing laying on the soil or in the top layer of soil is just called organic matter.  It’s in the active stage of being decomposed or broken down by soil organisms. Once organic matter has finished decaying and is a fairly stable product it is called humus. Humus slowly releases nitrogen, absorbs nutrients and water and keeps them available to plant roots and increases tilth, or soil structure.

Five to ten percent organic matter is a goal to strive for when improving your soil. Ideal soil composition for most plants is said to be 5-10% organic matter, 40-45% mineral soil, 25% water and 25% air.  (Note: a few plant species actually do better in soils with less organic matter.) Organic matter and humus do disappear in time and should be constantly renewed.

A soil is called organic soil when it’s at least 20% organic matter and those soils are usually “bottomlands”, once under water and formed from peat and other plants decaying and mixing with silt washed off surrounding land. They may be called peat or muck soil also. Often these soils are also acidic.  Some plant species will grow well in them, but others will not.

The organic matter in soil and the minerals that came from the rocks broken down in the soil determine the soil pH and the nutrients available for plant growth. They also determine the color of soil.   Soil color varies from light brown to reddish to almost black.

Top soil is the layer of soil closest to the surface and that soil generally has more organic matter or humus, therefore it looks darker.  Soil isn’t “better” because it is dark in color, nutrient rich soils can be light in color.  But it probably does have more organic matter and better soil structure.  (Be careful if you buy topsoil, it is generally collected from building sites or waste areas and can be filled with debris, weed seeds, and even dangerous chemicals.)  Darker soil does have the advantage of heating up faster in the spring especially if it’s well drained, because darker colors absorb the sun’s light and heat.

Soil water and air

As discussed above there are two types of pores in soil.  Smaller pores exist between the mineral soil particles and larger pores exist between soil aggregates. The smaller pores hold on to water and nutrients and the larger pores allow for drainage and air spaces, plant roots need air as well as water.  A soil is called saturated when all the large pores are filled with water and plants vary as to how long they can remain in saturated soil before their roots are killed.

The smaller pores usually have a film of water clinging to  them and these resist water being pulled away by gravity and remain available for plants for a longer time.  Since clay has the smallest pores it holds more water. The larger aggregate pores act like a house drain and water moves through them down deep into the soil, leaving empty spaces to be filled with air.
Organic matter absorbs water also and slowly releases it.  Water is moved from the small pores and organic matter by capillary action- water moving from a wet area to a dry area, plant roots absorbing water and evaporation at the surface.

Since plants need water, nutrients and air in the soil you can see why both soil texture and soil structure are important.  The mineral soil pores hold the water and nutrients plants need, the aggregate pores drain away excess water and hold air.

Soil organisms

Healthy soil teems with unseen life as well as creatures obvious to the eye. They aren’t structural components of soil but should be considered to be part of it.  Bacteria in soil are extremely important, they decompose organic matter and perform other chemical feats that make nutrients available to plants. An ounce of soil can contain over 30 billion bacterial organisms, both helpful and harmful.

The study of soil bacteria is fairly new, but researchers are now collecting soils from all over the world and trying to identify the bacteria in them and what they do.  Some are even being considered for human medicines. Some plant species need an association with certain soil bacteria to do well.  Legume seeds like beans are sometimes inoculated with soil bacteria to get them off to a good start.

Not all bacteria in the soil are good guys though.  Some cause plant disease and even human diseases. Tetanus is a serious, sometimes fatal human disease caused by soil bacteria.  Gardeners should keep their tetanus vaccinations up to date since they work with soil.

Fungi are also found in soil.  They are considered to be multi-celled plants but they don’t produce their own food, they break down other organic matter for food or sometimes live off plant sap.  They are important decomposers of organic matter in soil but some fungi also cause plant and animal disease.

Mycorrhizae are specialized fungi that interact with plant roots in a beneficial or symbiotic arrangement.  Plants provide food for them, but they send out a network of tiny filaments that are able to squeeze into soil pores to absorb water and minerals to pass to the plants roots.  About half of plant species in the world form mycorrhizae relationships.

Mycorrhizae are another organism that are being studied in great detail.  It is thought by some researchers that plants may communicate through a network of mycorrhizae and can share nutrients and water to other related plants through them.  This has not been conclusively proven.

There’s no evidence that supports buying concoctions that supposedly contain mycorrhizae and using them in the garden for plant health.  Save your money as these products don’t really work.

Other things found in soil include protozoa, one celled animals that are primarily decomposers, invertebrate animals like insects, slugs and earth worms, which have various roles in the soil ecosystem and vertebrate animals like moles and mice.

 I’ll stop here today.  Next week I’ll discuss soil nutrients and soil pH, very important things for a gardener to know about. For homework read one of the articles in the links below.

Irish Spring Cake   (LOL)

Here’s an easy but interesting cake for your St. Paddy’s day meal.  Good decorations for the cake include rainbow or green sprinkles or shamrocks.  The green inner streaking is reminiscent of the fabled soap and the flavor- well - think green beer.

1 white cake mix
3 large eggs (no need to separate whites and yolks)
Water called for in cake directions
½ cup melted butter
2 cups of lime flavored beer or a light beer with 2 tablespoons lime juice
1 package of lime flavored gelatin

½ cup butter, (one stick), room temperature
1 package (8 oz.)  cream cheese, room temperature
3 cups powdered sugar
1 tablespoon lime juice or extract
Green food dye - optional


Put 1 cup of beer in a small pan and heat it to simmering.
Add the gelatin and stir until dissolved.  Remove from heat.

Add the rest of the beer.  Set aside to cool.

Mix cake mix with eggs, melted butter, and water called for on box.  Beat until smooth and blended.

Pour into a greased 9 x 13 cake pan.

Bake at 350 degrees for about 25 minutes, until a knife inserted comes out clean. 

Let the cake cool to room temperature, cover, and then refrigerate 1 hour.

Make frosting – blend together cream cheese, butter and lime juice until smooth and well blended.

Add powdered sugar in 1 cup amounts, blending well until you have a thick, but spreadable frosting.  Add food color gradually, blending after each addition, until you have the perfect green for you.   You may not need all the powdered sugar.

Refrigerate frosting until ready to use.

Take cake out of the refrigerator and make sure it feels cool to the touch.  With a fork or skewer poke holes all over the top of the cake.

Pour the beer mixture evenly over the cake, it should seep into the holes.

Refrigerate cake until the gelatin/beer mix is well absorbed and gels, at least an hour.

Frost with cream cheese frosting.  Refrigerate until served.

Clover 4Luck Red-Green

May the luck of the Irish be with you

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:
(This is the Lapeer County Gardeners facebook page)
An interesting Plant Id page you can join on Facebook

Here’s a seed/plant sharing group you can join on Facebook

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