FERTILIZING 101
Feed Sooner, Not later
Although shoot growth of woody plants ground to a halt weeks ago, root growth will continue until soil temperatures drop below about 40 degrees Fahrenheit. Root and shoot growth of woody plants and lawn grass are asynchronous, with root growth at a maximum in early spring and fall, and shoot growth at a maximum in summer. So roots aren’t just barely growing this time of year; they’re growing more vigorously than in midsummer.
Remember the song lyrics: “House built on a weak foundation will not stand, no, no”? Well, the same goes for plants. (Plant with a weak root system will not be healthy, no, no.) Fertilization in the fall, rather than in winter, spring, or summer, promotes strong root systems in plants.
By the time a fertilizer applied in late winter or early spring gets into a plant, shoots are building up steam and need to be fed. Fertilization in summer forces succulent shoot growth late in the season, and this type of growth is susceptible to damage from ensuing cold.
They Hunger For . . .
The nutrient plants are most hungry for is nitrogen. But nitrogen is also the most evanescent of nutrients in the soil, subject to leaching down through the soil by rainwater or floating off into the air as a gas. The goal is to apply nitrogen so that it can be taken up by plants in the fall, with some left over to remain in the soil through winter and be in place for plant use next spring.
Two conditions foster nitrogen loss as gas. The first is a waterlogged soil. If you’re growing most cultivated plants — yellow flag iris, marsh marigold, rice, and cranberry are some exceptions — your soil should not be waterlogged, aside from considerations about nitrogen. (Roots need to breathe in order to function.) Nitrogen also evaporates from manure that is left exposed to sun and wind on top of the soil. Manure either should be dug into the soil right after spreading, or composted, after which it can be spread on top of the soil, or dug in.
Leaching of nitrogen fertilizer is a more common and serious problem, especially on sandy soils. The way to prevent leaching is to apply a form of nitrogen that either is not readily soluble, or that clings to the soil particles. Most chemical fertilizers — whether from a bag of 10-10-10, 5-10-10, or any other formulation — are soluble, although a few are specially formulated to release nitrogen slowly.
The two major forms of soluble nitrogen that plants can “eat” are nitrate nitrogen and ammonium nitrogen. Nitrate nitrogen will wash right through the soil; ammonium nitrogen, because it has a positive charge, can be grabbed and held onto negatively charged soil particles. Therefore, if you’re going to purchase a chemical fertilizer to apply in the fall, always buy a type that is high in ammonium nitrogen. The forms of nitrogen in a fertilizer bag are spelled out right on its label.
Go Organic
Rather than wade through the chemical jargon, nitrogen loss through the winter can be averted by using an organic nitrogen fertilizer. Nitrogen in such fertilizers, with the exception of blood meal, is locked up and held in an insoluble form. As soil microbes solubilize the nitrogen locked up in organic fertilizers, it is released first as ammonium nitrogen. So by using an organic nitrogen source, the nitrogen is not soluble to begin with, and when it becomes soluble through the action of microbes, it’s in a form that clings to the soil particles and not wash out of the soil.
(Except in very acidic soils, other soil microbes then go on to convert ammonium nitrogen to nitrate nitrogen. This reaction screeches almost to a standstill at temperatures below 50 degrees Fahrenheit, so the ammonium nitrogen can just sit there, clinging to soil particles, until roots reawaken in late winter or early spring.)
Common sources of organic nitrogen include soybean meal, cottonseed meal, fish meal, and manure. Hoof and horn meal, leather dust, feather dust, and hair are esoteric sources, though plants will make use of them as if they were just ordinary, organic fertilizers. Even organic mulches, such as wood chips, straw, and leaves, will nourish the ground as they decompose over time.
The Cadillac of fertilizers is compost. Compost offers a slew of nutrients, in addition to nitrogen, released slowly into the soil as microbes work away on it. Compost — most organic fertilizers, in fact — are not the ticket for a starving plant that needs a quick fix of food.
Every year I spread compost an inch deep beneath especially hungry plants like vegetables and young trees and shrubs to keep them well fed. Less hungry plants get one of the above-mentioned organic mulches. The benefits of these applications continue, trailing off, for a few years, so annual applications build up continual reserves of soil nutrients, doled out by soil microbes, that translate to healthy plants and soil.
(More details about fertilization can be found in my book Weedless Gardening.)
A DELECTABLE PEACH
A Time Machine
A few days ago, a fuzzy orb that I held in my hand became a time machine. This time machine was a peach, and time travel took place immediately after I took a bite out of it. There I was, no longer eating the peach on my friend Wendy’s farm — Wendy is a botanical artist, https://drawbotanical.com — but in the backyard of my youth, biting into a peach from our backyard tree. (Our home “orchard” also consisted of two crabapple trees, whose fruit was morphed under the direction of a great aunt into jelly, and a pear tree that I remember bearing only one fruit that I watched daily only to find it, one day, gone, picked prematurely by my sister.)
Back to the time machine peaches. These peaches would never sell at a supermarket, even a farmers’ market. Their skin was very fuzzy and a washed out yellow color, some with just a hint of a blush. I remember, when I worked for Cornell University Roger Way, the apple breeder at the time, bemoaning the fact that “Americans eat with their eyes.” Spots from peach scab disease on many of the fruits did nothing to increase their visual appeal.
“Would never sell,” that is, unless a taste was offered. Protected within that admittedly ugly skin was a meaty, golden yellow flesh. The flesh was sweet and, in contrast to most peaches these days, very rich-tasting, with a strong peachy flavor. It’s that peachy flavor that whisked me backwards in time.
I Make a New Peach Tree
Long gone peach
This year has been the best ever fruit year in decades around here, even right here on the farmden, where the low-lying site is not very fruit-friendly. Peaches always fail here; a few weeks ago I finally cut down my one tree. Twice over the past years I planted apricot trees, knowing that they are one of the fruits least likely to succeed around here. I was right; they are long gone.
Against my better judgement I am going to once again venture into peachdom. Perhaps Wendy’s peach is resistant to peach ills: brown rot, plum curculio, oriental fruit moth, bacterial spot, and peach scab. (Yes, her fruits were afflicted by scab, but not enough to diminish the pleasure of biting into them.)
Wendy isn’t sure of the variety name of her tree so I can’t order that one from a nursery. No matter.
Pits saved from some of the fruits can be grown into whole new trees. Seed-grown peach trees grow quickly and can take only three or four years before their branches are adorned by fruits. Plant a peach pit now, and it will not sprout until next spring, even if you keep it warm. Like other temperate-zone fruits, the seeds need to be stratified, that is, they must experience winter before they’ll sprout. If they sprouted now, the young, tender seedlings would succumb to winter cold.
Plant the pit outdoors, and it will be naturally stratified. I prefer to fool the pit by cracking the outer shell, soaking the seed in water for a few hours, then putting it in a plastic bag, along with moist potting soil, in the refrigerator. Refrigerator-stratified seeds sprout more quickly than outdoor planted seeds because once the outdoor-sown seeds have experienced enough cold, a total accumulation of about 1,000 hours of temperatures between 30 and 45 degrees Fahrenheit, they have to await spring warmth before they’ll grow.
Seeds stratified in the refrigerator will often sprout in the bag within a couple of months, at which point they need to be planted. I plan to pot them up and let them grow in the greenhouse.
Seed-grown fruit trees generally don’t bear fruit identical to the fruits from which the seeds came. It depends on what variety pollinated the flower that became the fruit, and how the chromosomes got juggled around. Peach trees are self-pollinating, which reduces the variability from fruit parent to fruit child, so there’s a good chance that a seed grown peach tree will yield tasty fruit. In contrast, plant an apple seed and there’s about one in 10,000 chance that the fruit from the resulting chance will even be edible.
If I wanted an exact replica of Wendy’s peach, I could beg a branch from her tree and graft it onto a peach rootstock. What’s a peach rootstock? It could be any peach tree grown from seed.
And Almonds!
Despite apricot’s strong nomination for the tree crop least like to succeed around here and, actually, pretty much everywhere in eastern North America, it does not win the prize. Almond trees are less likely to succeed. With that said, in this best of all years for fruit, here in the Northeast, at least, Wendy managed to harvest her first (and perhaps her only) crop of almonds this year.
Almonds are closely related to peaches. Their common ancestor diverged six million years ago with the separation resulting by the lifting of the Himalayan massif. Both plants suffer from the same insect and disease problems.
Two characteristics put almonds in the most likely to fail category. First, in humid climates, the nuts themselves are apt to spoil. And second, almonds have a very low chilling requirement. (Just as seeds have chilling requirements before they will sprout, flower and stem buds also have chilling requirements before they can sprout.) With a low chilling requirement, almonds would likely break dormancy and flower with the first hint of warm weather in spring, then succumb to likely subsequent frosts.
But not this year.
Needless to say, I will not be giving almonds a try on my farmden.
Almond illustration, by Wendy
FOXY GRAPES
A Bad Rap
The word foxy has not been complimentary to grapes. It refers to the dominant flavor in one of our native species, the fox grape (Vitis labrusca). Around 1880, the botanist William Bartram went so far as to suggest that the epithet foxy was applied to this grape because of the “strong, rancid smell of its ripe fruit, very like the effluvia from the body of a fox.” (Others more generously suggested the epithet came about because foxes ate the grapes, or because the leaves resembled fox tracks.)
Glenora and Vanessa seedless grapes
Although native Americans ate this grape, early white settlers, well before the time of Bartram, had been unimpressed by the flavor. In 1672, John Josselyn wrote that fox grapes had “a taste of gunpowder.” Two Dutchmen visiting New York in 1679 recounted how they “went along the shore to Coney Island . . . and discovered on the roads several kinds of grapes still on the vines, called speck [fox] grapes, which are not always good, and these were not; although they were sweet in the mouth at first, they made it disagreeable and stinking.”
Fox grapes
Wherever white settlers landed in America, they attempted to establish plantings of the grape with which they were familiar, the European wine or vinifera grape (V. vinifera), which was the grape cultivated in the Old World since biblical times. In America, vinifera culture began as long ago as 1619, when the best vines and skilled growers were brought from France to establish a vineyard in Virginia. That planting and virtually all subsequent plantings in the East failed because vinifera grapes can’t tolerate the cold winters or the insects and diseases to which our native grapes are accustomed.
What’s the Difference?
In spite of repeated, futile attempts at growing vinifera grapes in the East, few people considered growing our tougher, native grapes before the nineteenth century. Only then were superior varieties developed, beginning with Catawba about 1820.
One reason for the delayed interest in fox grapes was because vinifera is the better fruit for wine, and it was not until the nineteenth century that fruits generally were appreciated for fresh eating. (“Wine” recalls another possible source for the epithet foxy; horticulturalist Liberty Hyde Bailey suggested in 1898 that the name arose due to “the lively foxing or intoxicating quality of the poor wine which was made from the wild grape.”)
As you might imagine, fruits of vinifera and fox grapes are quite different. You can pick out the difference from the grocer’s shelf today. The fox grape is represented by Concord: bite into a berry and the thick skin slips off the jelly-like meat, releasing a strong, aromatic, though not excessively sweet, flavor. The vinifera grape is represented by Thompson Seedless: eat the whole berry, tender skin and all; the fruit is sweet, with a neutral flavor. Vinifera berries are less apt to shake off the bunches, so ship better, which is one reason why Concord grapes usually show up in markets only near where they are grown.
Concord grape
I Like Foxiness
All this verbiage isn’t an academic exercise in grape history. If you grow grapes, as I do, survival of the vines and taste of the fruits is important. Vinifera are occasionally grown with success in the Northeast, but 300 years of mostly failure should teach something.
For those gardeners who strive for a grape akin to vinifera, there are hybrids between vinifera and fox grapes. Actually, most grape varieties these days are hybrids of vinifera, labrusca, and often some other species. Hybrids exhibit the full spectrum in flavor, hardiness, and pest tolerance, depending on which varieties were used as their parents.
If you live in a environment inimical to vinifera grapes and you’re interested in growing grapes closer in flavor (or lack thereof, in my opinion) to Thompson Seedless, hybrids such as Himrod and Lakemont are fairly cold hardy and can be grown at favorable sites, preferably south facing slopes in full sun. A bit more foxy, unfortunately only fairly cold hardy, is Vanessa, a delectable small berry which is pale red, crisp, sweet and flavorful.
Vanessa grapes
I have grown one vinifera variety, thus far in a large pot in my greenhouse. This one, Perle de Csaba, and I’m sure some other viniferas, does have a distinctive, delicate flavor, besides being sweet and seedless, and wrapped in a tender skin.
Notwithstanding the previous testimony against foxiness in grapes, I happen to like my grapes foxy. And I’m not alone: Ulysses P. Hedrick, who wrote The Grapes of New York early in the last century, conceded that many vinifera grapes “are without character of flavor” compared to American grapes, which are “more refreshing . . . do not cloy the appetite,” and make a better juice. My taste preference is fortunate, because in my farmden, here in the bottom of the bottom of a frost pocket, grapes are particularly prone to both cold injury and disease.
Edelweiss grape
Despite my affection for foxy grapes, for many years my farmden lacked a good ol’ Concord vine. I finally planted one about 6 years ago, ate the fruit for a couple of years, then decided the flavor didn’t warrant my growing it. Yesterday I tasted a friend’s Concord grapes and they were delicious. What’s up? Did my nursery source for my Concord vine mix up labels? Could the difference be due to terroir, a concept that takes into account almost everything: soil, climate, slope, sunlight, the geology and geography of a particular region, and as much more as needed to lend it a certain mystical quality? (I delve into terroir in depth in my book The Ever Curious Gardener.) I took a cutting to make a plant and in a few years will check out the flavor of that “Concord” here.
For the past few weeks, I have Elmer Swenson, a dairy farmer and grape breeder who lived near the Wisconsin-Minnesota border, to thank for the grapes I am eating. Some of my favorite varieties reflect his skill as a breeder. Swenson Red berries are medium sized, sweet, fairly foxy, and just slightly slipskin. I do wish that Edelweiss was not so vigorous, but the berries are deliciously sweet and foxy. Also delicious and foxy is Brianna. And for a variety leaning towards the vinifera end of the gustatory spectrum, there’s Somerset Seedless. Thanks Elmer.
Fruit bowl with fig, grape, persimmon, nashi
