To Fertilize or Not To Fertilize, That is the Question

Looking out on my vegetable garden last week, I noticed some yellowing leaves on kale transplants. Perhaps the yellowing leaves were just a legacy from the kale transplants adjustment to their home outdoors. In the greenhouse, lettuce that I planted last month lacked its expected exuberance.  Perhaps slow growth of lettuce was my imagination.

Or perhaps the lettuces and kales needed some fertilizer. Vegetables are generally heavy feeders, and leafy vegetables especially so. My garden doesn’t get fertilizer per se; the plants get all they need from compost. Years ago I calculated that a one inch depth of fully ripened compost could thoroughly satisfy the nutritional needs of vegetable plants -- even intensively planted vegetables -- for a year, and that’s what my plants get. As an added benefit, compost, in contrast to chemical fertilizers and even most organic fertilizers, offers a wide spectrum of nutrients in addition to just the big three: nitrogen, phosphorous, and potassium.

Chemical fertilizers are salts (in the broad sense of the word, that is, any ionic compound and not only sodium chloride). Add them to the soil, and they are there for plant use. Not so for compost and most other organic fertilizers. To become food for plants, the latter must first be “mineralized,” that is, converted by soil microorganisms to ions.

Microorganisms grow more and more active with increasing heat and moisture (to a point), so perhaps my plants were hungry because cold or dry soil was keeping microorganisms sluggish. And any available nutrients, whether their provenance is chemical or organic, needs to be dissolved in water before a plant can slurp them up.

“April showers bring May flowers . . . “ blah, blah blah. Not so, at least in my observation the past few years. Aprils have tended to be dry. Dry soil slows plant growth and could be responsible for my kales’ yellow leaves. Mineralization is slowed and even if mineralized, insufficient moisture might be available to put those nutrients in solution.

A problem with slow mineralization could have been resolved by applying compost the previous fall. Lingering warmth in the soil permits some mineralization, and nutrients would be ready and waiting come spring (with a winter’s worth of water putting them in solution). Usually I apply compost in fall but last fall did not get to all the beds.

The problem has been resolved, simply, by watering. As supporting evidence, the drip line in one of the vegetable beds came loose from its source; kale in that bed remained sickly even as the watered beds sprung to life.

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For a quicker effect or where compost is not available, a concentrated organic fertilizer, such as soybean meal, might be in order. You might have guessed that soybean meal is high in nitrogen -- 7 percent -- since soybean seeds contain 40 percent protein and proteins are about 16 percent nitrogen.

More recently, I’ve also been using alfalfa meal as a source of concentrated, organic nitrogen for plants or beds that need it. Being a legume, alfalfa is also high in nitrogen, but the meal is made by grinding up leaves and stems rather than seeds, so it is less concentrated in nitrogen (2 percent) than soybean meal. Alfalfa is a deep-rooted perennial whose roots forage far and wide for nutrients to possibly offer a bigger smorgasbord to plants than does soybean meal. Alfalfa meal also contains triacontanol, a natural compound that stimulates plant growth (not that I’m necessarily looking for any artificial stimulation fro my plants, whether from sources natural or otherwise).

Both soybean meal and alfalfa meal are mostly used as animal feeds; as such, they are readily available at feed stores.

Neither soybean meal nor alfalfa meal is the end-all for fertilizing plants. A serious concern with both is that they are mostly grown from GMO seeds. Also, neither provides a sufficiently broad spectrum of nutrients. Soybean meal provides mostly nitrogen and potassium; alfalfa meal mostly nitrogen and phosphorus. And finally, neither provides bulk that comes from carbohydrate compounds. This bulk has far-reaching benefits, fluffing up soils for aerations, sponging up water, feeding beneficial microorganisms, and, in addition to providing nutrients, making nutrients already in the soil more available to plants. Compost, leaves, and straw are among the organic materials that offer bulk.

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Why the focus on nitrogen when talking about fertility? Nitrogen is the most evanescent of the big three nutrients, and the one most likely to need annual replenishment. Nitrogen can leave the soil as a gas, can be washed down and out of the soil by rainfall, and can be taken up by plants. A soil regularly “fertilized” with bulky organic materials will have plenty of all necessary nutrients but could be temporarily short of nitrogen. Unless that bulky organic material is fully ripened compost. Yay compost!

What's New Farmdenly?

In this early part of the growing season, I’m frequently asked, “So what new and exciting plants are you growing in the garden this year?” And just as frequently, I can’t think of anything. Not that gardening isn’t “new and exciting” every year, what with the vagaries of the weather and pests, and their interaction with planting, pruning, and soil care.

Well, this year I can think of at least four new and exciting plants I’m growing.

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I actually have grown cardoon before, perhaps 25 years ago. And up until this weekend, I had no desire to ever grow it again. The plant is like a giant celery with spiny stalks that must be tied together so that they get blanched and edible. Or supposedly edible, once you removed the tough strings running down each stalk. Blanching and de-stringing was a lot of trouble, too much trouble for me considering the taste of what of the tough stalk after being cooked.

This weekend, two people at my grafting workshop digressed from grafting to wax enthusiastic over cardoon. Evidently, my problems 25 years ago were growing the wrong variety and cooking it poorly. I’m not sure if any varieties were available back then, but I was convinced to order seed of the suggested variety, Gobbo di Nizza (Hunchback of Nice), and will sow them in pots as soon as they arrive.

Once the weather warms reliably, I’ll plant out two or three small plants, giving them rich soil. Once the plants are three feet high, I’ll mound some soil or wood chips up around their bases and tie the leaves together to blanch them, then a few weeks later, cut down the four-foot-tall monsters for eating. I was told that they taste like artichoke, a close relative.

In warm winter regions, cardoon grows as a perennial. If winter’s were warm here, I’d plant cardoon even if they tasted awful. That’s because in their second year, they send up six-foot-high stalks capped with bottlebrushes of cerulean blue flowers that sit in an artichoke-y base.

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I’ve also previously grown -- or tried to grow -- the second of this year’s N&EP (“new and exciting plants”), King Red Russian olive. It’s a variety of Russian olive, native to Afghanistan, that, instead of bearing the usual innocuous silvery green fruits, bears bright red fruits. The fruits contrast nicely with the silvery green leaves -- and taste pretty good.

For some reason, King Red doesn’t like our summer weather, probably the humidity. My plant of yore grew fine until sometime in July, when it collapsed, dead. Others in the humid East have had similar experiences.

Out West, King Red, which was introduced as a conservation plant decades ago by the USDA, grows fine. Too fine, so that it is now listed as an invasive plant out there, along with regular old, green-fruited Russian olive. (Sometimes they are listed so in the East also, although they seem pretty sedate around these parts.)

I’m thinking that somewhere in the genes of King Red, which is a seed propagated variety, not a clone, might lie genes that can tolerate our summer climate. To that end, I got my hands on seeds left from a bag of imported, dried King Red fruits; I’ll sow them all and hope for the best. (I once tasted the dried fruits; they are like sweet talcum powder, enclosed within a brittle “shell.”) The fruits parade under a number of aliases: Trebizond date, lotus tree. Botanically, it’s Elaeagnus angustifolia var. orientalis.

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Another fruit, Ficus Afghanistanica, or mountain fig tree, is among my N&EP. With more than a half-dozen fig varieties in my not very fig friendly climate, you’d think I had enough figs. Mountain fig tree is worth a try for its hardiness, by some accounts to well below zero degrees F. Of less importance here in the humid East is its drought tolerance, which may be related and help with its cold hardiness.

Also on the plus side, the plant has decorative leaves, similar to common fig leaves except pointed at their tips.

On the negative, there’s some question as to whether this fig needs pollination, something most fig varieties do not need. If so, a special pollinator variety would be needed as well as some means to get the pollen into the eye of each fruit at the right time. A syringe filled with pollen? Figs that need pollination normally get their pollen with the help of Blastophagus, which are tiny wasps that, laden with pollen, enter the eyes of developing fruits to lay eggs and, in so doing, inadvertently pollinate the flowers within.

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The buttery pleasure of eating hickory nuts is offset by the tediousness of cracking and shelling them. That’s shagbark hickories (Carya ovata), which are native throughout eastern U.S.

Shellbark hickories (C. lacinosa) have similar nut flavor and shape, except that they are two or three times larger, so you get more bang for your buck with each nut you crack. Walking just a quarter of a mile in any direction, I’d be likely to find some shagbark hickory nuts on the ground but nary a shellbark hickory. The latter species is found mostly along the Ohio and Mississippi Rivers, and bordering regions; nowhere, though, is it common.

So I ordered trees from Nolin River Nut Tree Nursery, and not just any old shellbark trees, but the varieties Simpson and Selbhers. Both are billed as heavy bearing and producing nuts medium to large nuts with excellent cracking qualities. Very “new and exciting;” I hope to enjoy the nuts of my labor in 5 to 10 years.