Good Nutrition

What does it take to make a tree?  Part of the answer lies in the soil.  It was my job last week to guide a group preparing to become Certified Arborists into the world of tree nutrition.  We started with the Periodic Table, noting that fourteen soil-borne elements are essential and four are beneficial to the happiness of a tree.  I wanted to sing my way through the Table, a la Tom Lehrer in 1959, but I spared everyone that pleasure and just concentrated on the dry facts of plant science.

Like most other plants, a tree’s greatest nutrient need from the soil is nitrogen, which is a key component of many functions, including photosynthesis.  Nitrogen can also be a limiting factor, since it is a rather slippery character and sometimes in short supply.  Microbes and lightning can put nitrogen into the ground, but it can leach below the roots or return skyward through volatilization.  Among its many other benefits, organic matter (such as compost) is beneficial to plants since it supplies nitrogen.  Plants deficient in nitrogen will show  stunted growth, reduced root systems and yellowing older leaves, since the little nitrogen existing in the plant will move to the newest leaves and shoots in an attempt to keep them green.  

Another important element is iron.  At a young age, I remember my oldest living relatives (born in the nineteenth century!) speaking of having “tired blood,” which may have been iron deficiency.  Plants can experience this, too, especially those we call acid-lovers, which include blueberries, rhododendrons, azaleas, and mountain laurels.  When soil pH is relatively low, or acidic, iron is freely available and these plants do well.  Raise the pH, however, and the iron in the soil becomes less readily available, and the acid-lovers suffer.  The primary symptom, once again, is yellowing foliage, this time throughout the plant  and in concert with distinctly green veins.  Horticulturists call this “interveinal chlorosis,” a term I encourage you to drop at your next cocktail party in order to raise the comment, “this guy must be some sort of plant doctor.”

In the tree world, the classic example of iron deficiency is pin oak (Quercus palustris).  This normally attractive tree is sometimes planted along city streets, since it can take some of the abuses urban life hurls at green plants.  Unfortunately, many factors raise the soil pH in an urban tree pit, including the aging of sidewalks, which are made from lime-based materials.  It is therefore not uncommon to see a bright yellow pin oak in a state of full, glorious iron chlorosis. 

Fixing an iron deficiency in both people and plants is possible.  While great-grandmother took a swig of the potion bought from the traveling medicine man, gardeners can lower the soil pH with sulfur, which makes more iron available and yellow plants greener.  A faster fix is to spray the plant with chelated iron, which will re-green it almost overnight, a cool trick.  It’s no wonder plant people are the life of any party.          

Turfgrass Follies

Although gardening has been described as the slowest of the performing arts, lawns seem to revive overnight.  Seeing that blanket of soft green under the still-dormant oaks and just budding red maples does the soul good.  But look a little closer and it’s apparent the lawn could use some work.

Snowplows, snowblowers and cars running off the driveway create ugly bare spots.  Unfortunately, getting grass seed to germinate in spring can be tricky, since soils remain chilly.  Perennial ryegrass is the species to choose, because it germinates much faster than fescues or ryegrasses.  Putting ¼ inch of fine, dark-colored compost on top of the seed, or covering the seeded patch with vegetable-garden rowcover fabric, can hasten germination significantly.  A special lawn starter fertilizer can also help. 

Early spring is also soil-testing season.  When people see moss in a lawn, a good number of them rather inexplicably reach for a bag of lime.  I apparently missed it, but sometime in everyone’s American grade school curriculum a teacher intoned, “Moss in your lawn means that the soil is acidic,” and the statement is taken as gospel.  Sorry, sir, but after 30 years of soil testing, I know this just isn’t true.  Moss can grow on soils with a high pH, and adding lime to them will only make the situation worse.  Just this week a gentleman brought in a moss/soil sample and the pH turned out to be 8.0, quite alkaline.  We told him to look for a big bag of sulfur (to lower the pH), and start spreading.

So why the moss?  Moss is a poor competitor for a vigorously growing lawn, so there must be reasons why the lawn, or even weeds, aren’t thriving.  Perhaps it is too shady; grasses aren’t lovers of life in the dark.  There is a very good chance the soil is low in nutrients, including one or more of the big three – nitrogen, phosphorous, and potassium.  Maybe damage from grubs, chinch bugs, fungal diseases and drought has so weakened the lawn that very little desirable grass remains.  Without a good population of Kentucky bluegrass, the most vigorous spreading grass, a lawn doesn’t have the ability to fix the damage that happens to it.  A little fertilizer and generous overseeding often goes a long way. 

Another springtime rite-of-passage is raking.  Websites confidently recommend raking your lawn in spring for any number of reasons, but there is a dirty little secret they don’t know about:  raking activates weed seeds.  Take broadleaf plantain, Plantago major.  Its seeds can remain viable in the soil for up to sixty years, which means your grandparents broadleaf plantain can come back to haunt you.  However, plantain seeds need light to germinate, so if they are buried beneath even a particle of soil, they stay dormant.  Pity the fools who go out with their rakes, unwittingly scratch up the ground, and give an entire colony of plantain seeds the green light to germinate.  So, put down the rake, and go ride your bike or fly a kite.       

Go BIG!

Big trees command our respect.  I keep busy year-round picking up the constant rainfall of dead twigs from my ancient backyard sugar maple.  I carefully mow around it in summer, and pray an ice storm doesn’t take it down in winter. Its shade allows us to live without air conditioning, and its age lends my garden a sense of rootedness that a sugar maple sapling couldn’t convey. 

Live with a big tree, and it starts to make sense that some of the ancients worshipped them.  How does a living thing get to be so huge?  Think of the high winds, ice storms, and lightning bolts a monster tree survives.  What can a big tree tell us about the environment, and how conditions have changed over time?  Big trees make gardeners feel humble, since no person can live long enough to grow a truly big tree from a seed.

Although most of us don’t exactly worship big trees, we can still celebrate them.  Searching out and tabulating noteworthy trees is one way to accomplish this.  American Forests, a pro-tree group, has maintained a national register of champion trees since 1940, and today you can see the current tally of nearly 900 specimens on their website (Americanforests.org).  The register has been described as the “hotbed of new champs, dethroned favorites, and much-sought-after bragging rights.”  One of the kings of the register surely must be the coastal redwood (Sequoia sempervirens) living in Jedediah Smith Redwoods State Park in California.  This national treasure is 321 feet tall with a 75 foot spread and a trunk measuring 950 inches in circumference.  The largest American holly (Ilex opaca), found in Rosebud, Arkansas, is much shorter, but still an impressive 64 feet tall with a trunk of 182 inches circumference.  Champions are based on adding trunk circumference, height and ¼ of the average crown to achieve a point total.  Trunk circumference is measured at 4 ½ feet from the ground.  The tree with most points wins; in case of a tie, co-champions are named.  A list of national challengers, or runners-up, is kept in case something should befall the top tree.  It all sounds much more civilized than our Electoral College system. 

New York also has a state list of giant trees, kept by the Department of Environmental Conservation.  Rensselaer County can proudly claim one champion.  Trojan Warren Broderick found the largest dotted hawthorn (Crataegus punctata), which measures 20 feet tall with a 75 inch trunk circumference.  Another former champ from Rensselaer County, a giant eastern cottonwood (Populus deltoides), was de-posed by larger trees from Clinton and Livingston counties, which are currently serving as co-champions.  There are no kings from Albany and Columbia counties, but maybe no one there is looking carefully enough.  The tallest-of-all honor goes to two eastern white pines (Pinus strobus), both 152 feet tall, and living in Warren and Franklin counties.  Are these the biggest white pines in the state?  Perhaps, but go for a walk and find one bigger!

What's Hot?

With increasing sunshine and warmer days, the perennial garden and I are awaking from a long winter slumber.  Soon will come time for the garden’s annual check-up.  What’s spreading too much, in the wrong place, or come up dead?  Local garden centers are happy to oblige with new perennials, supplied by local growers like Joe Behn.  He owns a local wholesale nursery and provided me with a list of new perennials he’s offering for 2019.  Here are just a few which have piqued my interest.        

Developing more compact plants is a big gardening trend, as people grow more in containers and smaller backyards.  One of my perennial favorites is turtlehead (Chelone), a late-blooming native of about three feet.  New is Chelone ‘Tiny Tortuga,’ which has similar hooded pink flowers but on a fifteen inch plant.  It promises to attract butterflies, resist deer and thrive in full sun to partial shade. 

As a lover of ornamental grasses, I’ve been disappointed as Miscanthus has fallen from grace over allegations of invasiveness.  To the rescue now comes Miscanthus sinensis ‘Scout,’ a green and white upright variety growing to about six feet, developed by the University of Georgia.  It claims to be infertile, so it won’t leave errant progeny down the road.  Other new sterile forms worth checking out are ‘My Fair Maiden’ and ‘Bandwith,’ both hailing from North Carolina State University.

There’s little better than hosta, those hardy dwellers of shade and sun which are practically indestructible.  While some swoon over the diminutive types like ‘Tiny Tears,’ I like to go big, along the lines of ‘Princess Wu,’ daughter of ‘Big John.’  So that’s why I’ll make room for the new ‘Humpback Whale,’ a blue-green hosta growing three feet tall and a whopping 6 ½ feet wide.  The leaves, the size of good-sized serving trays, have an unusual hump in the middle, making the leaf-tips point downward and giving rise to the name.  Bred by the late Mildred Seaver, the legendary hosta maven of Massachusetts, a plant of ‘Humpback Whale’ sold for $3,700 at the 2006 American Hosta Society Convention.  And we all thought those plant-society types rather sedate, didn’t we?  Thanks to Mrs. Seaver and all the other dedicated plant breeders, horticulture is hot!

Chaste Tree (Vitex agnus-castus) and I discovered each other in the summer of 1984, while I interned at Colonial Williamsburg.  The small trees with spiky blue flowers seemed a southern novelty to this Yankee, but new a new, cold hardy type is now marching north.  Vitex ‘Blue Diddley’ purports to grow from three to six feet tall and bloom on new wood in full sun.  Its USDA Hardiness Zone ratings range from sub-tropical 9b to locally brisk 5a.  It should be treated like a perennial plant here, expected to die-back to the ground in winter but re-grow the following year.  According to one source, chaste tree leaves were used in ladies bedding to “cool the heat of lust” when men were off to war.  Use this plant with caution.

The Dogwood With More

Even non-plant people know forsythia.  In these parts, it is the classic harbinger of spring, with its brassy yellow blossoms appearing along with the red-winged blackbirds, chorusing frogs and Florida snowbirds.  But there is another woody plant, with just as much yellow appeal, which pops even before forsythia.  It is the cornelian cherry dogwood.

You are forgiven if you’ve never heard of this dogwood, which botanically goes by the name Cornus mas.  While many know the flowering dogwood, and some have heard of the kousa and red-twigs, cornelian cherry is not a standby of the nursery industry and therefore doesn’t often show up in garden centers.  It does have a lot going for it, most notably its ultra-early floral display when it cloaks itself in tiny blooms.  This happens reliably each year, and while it might not compete with the showiest of magnolias or cherries, it beats them all to the punch, when we most desperately need some eye-candy.  Ever see a magnificent magnolia hit by frost?  That brown, mushy disaster is less likely to happen with a cornelian cherry, since the blossoms are resistant to temperatures down to 18 F.  

Usually grown as a small, rounded tree, perhaps reaching 15 to 20 feet, C. mas in full bloom looks especially good in front of a red-brick building, and is sometimes deployed this way in urban landscapes and college campuses.  Trees develop gray-brown to deep brown exfoliating bark, which provides character, and tend to be more adaptable than most other dogwoods as to sun exposure and soil.  It also exceeds its kin in being quite insect and disease resistant.  Cultivated examples well over 100 years old are known, which is positively ancient in the small tree world. 

The last characteristic I’ll describe, fruit production, can be looked at in at least two ways.  At Rutgers, we were taught that the large, bright red fruits, often borne in great abundance, were a nuisance.  Don’t plant a cornelian cherry dogwood near a walkway or building entrance, it was said, because everyone will be traipsing through the mess on the sidewalk and dragging it indoors.  Certainly true.  There is much more at hand than messy feet, however.  Cornus mas is native to eastern Europe and western Asia, and has been part of the regional people’s diet for some 7,000 years.  Initially quite tart, the fruits reportedly take on a sweeter, more plum-like flavor as they fully ripen, making them useful for fresh eating as well as for preserves, wine, pies and baked goods.  Unfortunately, I’ve never sampled one, so I’m no help here, but I pledge to nibble on some in the future.  Rich in a variety of vitamins and minerals, including the always-important “C,” the fruits also contain significant levels of calcium pectate fiber, which can positively impact cholesterol levels, and anthocyanin, an anti-oxidant.  Large pits, difficult to remove from the fruits, and a prolonged period of ripening are challenges to wide-scale production, but cornelian cherry might just be a super-food of the future.      

Book Recommendation -  Kids and Vegetable Gardening

Signs of spring are finally  sprouting, and children are waiting to splash in the puddles and, if properly conditioned, maybe also willing to dig with you in garden soil.  To that end one of the following books should be strategicly squeezed into  one of their egg baskets along side  all the choculate rabbits.  This list of relatively new books was compiled for me by Molly Chatt, Head of Youth Services for the East Greenbush Community Library in Rensselaer County.  Many of the titles will be available from your local public library, and all are availble from either bookstores or online sources. Happy reading and digging...

• Armstutz, Lisa J. Edible gardening: growing your own vegetables, fruits, and more.  Capstone Press,  2016

• Craig, Joe Archer & Caroline.  Plant, cook, eat!: a children's cookbook.  Charlesbridge Publishing, Inc..  2018

• Batholomew, Mel. Square foot gardening with kids: learn together: gardening basics, science and math, water conservation, self-sufficiency, healthy eating. Cool Springs Press , 2014

• Biggs, Emma. Gardening with Emma: Grow and Have Fun: A Kid-to-Kid Guide. Storey Publishing 2019

• Brown, Renata Fossen. Gardening lab for kids: Garden art: fun experiments to learn, grow, harvest, make, and play. Quarry Books 2017

• Cohen, Whitney and John Fisher. Gardening projects for kids: 101 ways to get kids outside, dirty, and having fun. Timber Press 2012

• Gaines, Joanna. We Are the Gardeners. Thomas Nelson 2019

• Hendy, Jenny. The best-ever step-by-step kid's first gardening: Fantastic Gardening Ideas for 5-12year olds, from growing fruit and vegetables and fun with flowers to wildlife gardening and outdoor crafts. Southwater 2014

• Kuskowski, Alex. Super simple salad gardens: a kid's guide to gardening. ABDO Publishing Company 2015

• McDougal, Nancy and Jenny Hendy. 300 step-by-step cooking & gardening projects for kids: the ultimate book for budding gardeners and super chefs with amazing things to grow and cook yourself, shown in over 2300 photographs. Lorenz 2012

• Torino, Stacy. Project Garden: A Month-by-Month Guide to Planting, Growing, and Enjoying ALL Your Backyard Has to Offer. Adams Media 2012

Adopted from an April 8, 2019 post from the Rensselaer County Vegetable Blog

by Irv Stephens, Master Gardener

And remember...

"Teaching children about the natural world should be seen as one of the most important 

events in our lives." - Thomas Berry

SOIL TEMPERATURES  IMPORTANT FOR SEED GERMINATION

In early spring excited gardeners like talking about the "growing season"  characterizing it as being wet, dry, cold, warm, early, late, etc.  But what exactly is a "growing season"? A "growing season" is  commonly recognized as the average dates between the last frost of spring and the first frost of autumn  delineating the span of time  plants have to complete their annual growing cycles. 

In most of Rensselaer County, the historical growing season covers about 150 days. Recent data  from the US Environmental Protection Agency shows that New York's growing season since 1970 has increased to around 160+ days. This means that our favorite vegetables have ample time to sprout, grow and  be harvested because most of these vegetables complete their growing cycles within just 85 to 120 days. The downside is that the longer season reflects the effects of global warming that also may bring more extreme weather events such as heavier rainfalls, higher temperatures in summer, and the arrival of new pests from southern climes -- things that vegetables don't like.

Home gardeners, however,  need to focus on more than just that last  frost in order to get a head start on either spring or their neighbors.  Some other important factors affecting a given year's "growing season"  include air and soil temperatures, rainfall patterns and soil moisture as well as light levels to name a few.  Of these, air temperature is arguably the most critical factor as it  provides the energy (i.e. heat) that determines  a plant's germination and growth rates.

Cool weather vegetables such as peas, spinach and radishes will start to germinate in soil temperatures around 40°F, while warmer weather crops such as bush beans, cucumbers and squashes germinate at soil temperatures starting at around 60°F.  The two charts below clearly illustrate these differences in seed germination requirements.

Sugar snap pea. Source: Johnny Select Seeds

Bush bean. Source: Johnny Select Seed

For both peas and bush beans, optimal seed germination occurs at distinctly warmer soil temperatures than threshold temperatures, germination rates increase up to a peak soil temperature and then decline eventually ceasing as soil temperatures exceed the optimum point.   Seeds planted at or near their peak germination temperatures  sprout faster and may emerge within only a few days. Seeds planted at threshold gemination temperatures will take longer (e.g. a couple of weeks or more) to germinate   and emerge because their chemical activities, although triggered,   are occurring  at  much slower rates.  This means that it may not be advantageous to put seeds in the ground at the earliest possible time if   air temperatures are forecast to remain around  germination threshold levels.

Home gardeners also need to note that seeds of different vegetables  respond differently to soil temperatures that are too cool or too warm for germination.  Radish and parsnip seeds can be planted in soils below their threshold germination temperatures. They will just sit and wait until soils warm up.  Bush bean seeds planted in soils below their germination threshold run a high risk of never sprouting and just rotting as their seed casings soften from soil moisture.  In summer, high soil temperatures near the surface will cause some plant seeds, e.g. many lettuce varieties, to go into a dormant state. 

Measuring Soil Temperature

I use a metal bulb soil thermometer to check soil temperatures in spring before planting seeds or setting out seedlings.  You can also use typical household thermometers as long as their scale goes down at least to 32°F, but you may have to use a screwdriver or small trowel to soften the soil before inserting  those plastic models into the ground.  I measure  soil temperature at a depth of 6."  Soil temperatures will be warmer, of course, closer to the surface which will be better for seeds, but I am looking for temperatures that roots will like after the seeds have sprouted.

Metal bulb soil thermometer

After  seed germination and young plants emerge, air temperature becomes the critical factor in regulating the rate of plant growth and development.   Most vegetables thrive in temperatures akin to comfortable room temperatures,  i.e. between 60° -  80°s F with 78°F frequently mentioned as being the sweet spot.  I recommend gardeners consult Cornell's  Home Gardening Vegetable Guide for information about growing most garden vegetables.  And for now,  let's just note that for vegetables, in general,  their growth mostly ceases when air temperatures reach and/or surpass the mid-90°s F.  More about plant growth, temperatures and GDDs (Growing Degree Days) will be covered in future posts.

Adopted from a March, 2018 post from the Rensselaer County Vegetable Blog

by Irv Stephens, Master Gardener

HOW TO PROTECT SEEDLINGS FROM DAMPING-OFF

Probably a lot of backyard  gardeners by now   have put seeds in pots, trays or some other kind of container. After anxiously waiting for the little sprouts to poke out of the soil, they are excited to see the first two leaves open, the cotyledons. The gardeners provide a little more water  and  maybe rotate the trays so that the new sprouts share the light.  Like the gardeners, the new sprouts must be  happy. What could possibly go wrong?  

Damping-off. Source: Cornell University 

There's actually a lot,  but most probably  a gardener will go down into their cellar or out onto an unheated sunroom one morning to check on the seedlings and find them sprawled over  with their stems looking pinched and maybe their leaves starting to look discolored.   Pulling up one of the shoots the gardener notices that its roots have not developed very much. What happened?

Looks like damping-off (or damp-off)  to me. 

Damp-off is  typically  caused  either by one of two fungi:  Fusarium spp. and  Rhizoctonia spp. or by a Pythium spp. ["spp" stands  for subspecies]. The latter is a water mold and is recognizably distinctive  because of its tiny white filaments. A microbiologist would say that it's distinguished  from fungi by being diploid (i.e. having 2 sets of genetic material rather than  being haploid like fungi with only 1 set). The two fungi may or may not appear with some kind of obvious fuzz, but infected plants will show various discoloration, and sometimes seeds will not even emerge from the soil.

Damp-off in early spring garden.

All these pathogenic critters are generally present in garden soils just waiting for the right conditions, like the ones some gardeners inadvertently  provide, to spring into action.   The pathogens do not normally have much impact on maturer plants, but they can. For example, the Irish Potato Famine was caused by a water mold (Phytophthora infestans). It commonly shows up at the end of  summer or during autumn as "late blight" when the weather turns cool and  wet.

Gardeners may not  care much about whether  a fungi or a water mold  did  in their  tomato seedlings, but they do need to know how to avoid the conditions that trigger "damp-off." The peppers in the pot of the first photo either were not in a sterile pot  or in sterile  garden soil, perhaps both. The second photo shows the result of someone in a hurry to get seed in the ground and not waiting until the soil was a little drier and/or and a little warmer,  On the other hand, maybe that gardener was just unlucky and hit a really bad streak of spring weather. Obviously, gardeners cannot control the weather, but here's what they can do next time to reduce the risk of pathogens from winning.

• Clean gardening tools and wash your hands before handling seeds or seedlings if you have been handling unwashed tools, pots and other containers.

• Use a heat mat under your tray or pots to keep soil temperature in the low 70s° F.

• Invest in sterile starter or planting soil.  Don't use soil from the garden.

• Wash and sterilize  trays and pots before use. Soak'em in a 10% solution of household  bleach.

• Don't overwater and make sure pots and other containers have drainage holes.  Seedlings  like to be moist, but not drowned.

• When watering, use  warm tap water to promote root growth. Roots do not enjoy  cold baths.

• After the first 2 - 4 true leaves develop (not the very first 2 leaves, the  cotyledons), recheck the potting mix's label because  many starter mixes contain slow release fertilizers at the right strength.  If they do, don't fertilize.  If you have to add fertilizer, then add it at no more than 1/4 strength.  

• Look for excessive condensation on the inside tray or container covers. If moisture is dripping down, remove the covers, shake off the condensation and allow for more air flow. 

• Provide 12-14 hours of light each day from either a soft white fluorescent bulb or a grow light. 

Remember that you are creating  a  nursery for young plants, and the seedlings will benefit from whatever  head start you take care to provide...

Adopted from an April, 2018 post from the Rensselaer County Vegetable Blog

by Irv Stephens, Master Gardener