Archives for posts with tag: green fertilizer

It turns out that when I was describing the benefits of crop rotation two weeks ago (see May 4, 2014), I was only half right. The process can be much more complicated—and substantially more advantageous—than merely planting different families of plants in different plots each season. The key is choosing what to plant and the order in which to plant it.

A good example of a more scientific approach to crop rotation is described in an Op-Ed piece by Dan Barber, chef of the restaurants Blue Hill (in New York City) and Blue Hill at Stone Barns (in Pocantico Hills, New York), that appears in today’s New York Times (see “What Farm-to-Table Got Wrong”).

Chef Barber buys his wheat from a farmer in upstate New York. On a visit to the farm, he learned that the wheat is only planted at the end of a four-year cycle of carefully selected crops, each of which performs a specific task for conditioning the soil. The procession follows a basic order which can be modified as soil response and weather patterns dictate.

First up is a cover crop such as mustard, which cleanses the soil and adds nutrients. Next is a legume to fix Nitrogen. Rye follows which, apparently, crowds out weeds (and also “builds soil structure”, although no explanation is given as to what exactly this means). Last to be planted is the wheat, the crop that outsiders (and until recently, Chef Barber) would think of as the whole point of this enterprise.

What is lamentable in the wheat farmer’s case is that the market for what those outsiders might call the off-season crops—the mustard, peas and rye—is scarce. While the wheat commands high, New York City prices, the other vegetables and grains go unwanted and often end up as feed for animals raised as food. Such use is not considered by most experts to be a very efficient use of resources.

Chef’s response to this situation was to develop menu items at his restaurants that incorporate the lesser crops and thereby elevate their stature and, presumably, their price (I hope that he pays his farmer as much for the mustard, peas and rye as he does for the wheat). It’s an elegant solution—a no-brainer, in retrospect—and also a win-win. Really, it’s a win-win-win because not only do the farmer and the chef benefit but the patrons of Blue Hill get tasty meals out of it, too.

So, how might this concept apply to the backyard gardener? Well, I’m not sure about growing an entire planter full of rye or mustard but half of a planter mixed with other like vegetables or grains might work (especially if Chef shares his recipes). And I never feel like we have enough Sugar Snap peas so the year of legumes would not be a problem. The primary issue is space, something we never seem to have enough of.

Maybe the question for me is, where can I put two more planters?


My second least favorite garden activity: Digging holes in our rocky, clayey soil. (Long-time readers of this blog know what my least favorite garden activity is; new readers can look at January 7, 2012 for a clue.) Unpleasant as it is, I have to face up to it if I want to be ready in time to plant summer squash and cucumbers over the Memorial Day weekend. More specifically, I need to start digging if I want to plant them in a different place from last year.

And I do want to plant them in a different place. Most gardening experts advise rotating crop locations every year. Moving vegetables in the same family around the garden helps protect them from insects and diseases that can hunker down in the winter and lie in wait for the new season’s plantings. Given our problems with cucumber beetles, aphids, bacterial wilt and powdery mildew, it is worth the effort.

Many sources advise a four-year rotation. Because crop rotation also helps balance demands on the soil (heavy feeders one year, light feeders the next), the suggested schedule sometimes includes a season of so-called green manure (peas, buckwheat, winter rye, alfalfa) to replenish nutrients or a cover crop to stifle weeds. I love the concept even if we cannot afford to lose any planter space to vegetables we do not plan to eat.

Any separation of the rotating groups is beneficial but to be maximally effective, there should be as much distance as possible between the individual planting areas. I’ve seen recommendations of up to a quarter-mile. That sounds good for large-scale growers but a quarter of a mile from my garden is practically in the next county. We’re very limited by the space available to us.

So we do the best we can. We have two raised planters and each year we alternate what goes into them. Last year, we planted cucumbers behind the west planter; this year, we will move the cukes to a similar location behind the east planter. And after laying out a dozen mounds for squash, we only dug and planted half of them last year, in a staggered arrangement. This time around, we’ll plant the other six. The separation is not huge but it’s not zero, either.

Which leads me back to the digging. It’s not my favorite activity but when it is done, the garden will be in a better state (and I shouldn’t have to do it again next year).

Having harvested the last of the string beans (see September 25, 2013), we decided it was time to clear out the vines and start readying the west planter for winter.  Some gardeners would chop up the vines and till them into the soil to decompose and add organic matter (so-called green manure or green fertilizer).  Others might cut the stems off at the ground surface and leave the roots in place, hoping that symbiotic bacteria (if present) would continue to fix Nitrogen in the soil.

But neither of these ideas appeals to me.  Even though the planter is not that big (four feet by 12 feet), turning the soil would be a lot of work.  And anyway, we are following the no-till approach, which moderates decomposition, improves drainage and minimizes weed growth by leaving the soil surface undisturbed.  Somewhat ironically, it also maintains better aeration by eliminating compaction and encouraging the earthworm population.  In fact, our soil is essentially turned over several times a year by an abundance of energetic Lumbricidae.

Leaving the roots in place would require less effort—even less than pulling them out.  However, we do not necessarily have Nitrogen-fixing bacteria and it is not clear that they would have enough time to make a significant contribution to the properties of our soil.  Besides, it is more likely that we have too much Nitrogen rather than not enough (see June 22, 2013), as evidenced by our crops of carrots, beets and radishes which produced more leaves than roots.

Being completely honest, it probably wouldn’t matter if either alternative had a scientific justification because pulling the vines out is more in keeping with my nature.  I have been described as a neatnik and it is a characterization I do not deny.  At a certain level, getting the planter tidied up for its long winter nap is much more important to me than ensuring that the soil has a proper concentration of Nitrogen.  Our soil’s nutrient distribution can be adjusted in other ways and at other times but I have to look at the empty planter all winter long.

One of the benefits of growing plants indoors in compartmentalized seed trays is that no thinning is needed.  We sowed one seed per compartment and they either germinated or they didn’t.  No effort or thinking is required.

The planters outside are another matter.  The smaller seeds—the carrots and turnips—were sown “thinly”, a qualitative term meaning closely spaced but not touching (the only quantitative definition I’ve found says to space them at three to four times the size of the seed).  Small seeds are difficult to place, however, and in practice they can wind up clumped together.  Consequently, when they germinate, the sprouts are literally on top of each other.

The larger seeds—the beets and radishes—are easier to place but some of them still end up too close together.  If nothing is done about them, they will hinder each other’s growth and stifle root development.  And for these vegetables, whose roots are what we eat, that would mean the failure of the crop.

So, we thin.  Or, to put it more harshly, we cull, pulling out the weaker seedlings so that the stronger ones can thrive.  Where there is no obvious choice, we remove seedlings to result in a uniform spacing.

And actually, I do not pull the seedlings out.  Doing so would loosen the soil and could damage the roots of the nearby seedlings that remain.  Instead, I use a pair of small clippers to cut the seedlings off at the soil line, leaving the ground undisturbed.  The beheaded roots will stop growing and, as they decompose, add organic matter to the soil.  In the case of the peas, the roots are especially enriching (they can be grown as “green fertilizer”).

The seedlings are still very small so I only thinned the most closely spaced ones.  After I was done, there were no spaces between sprouts smaller than a half-inch or so.  When the seedlings get larger and again start to encroach on each other, I will thin them at least once more to achieve a spacing closer to three inches for the turnips and beets and one to two inches for the carrots and radishes.

I did not attempt to thin the carrots yet.  Their seedlings are still small and frilly and I can barely see them let alone clip them.  When they get a bit larger, I’ll take a stab at them.  I also left the pea shoots.  They are already spaced at about an inch (their final spacing will be four inches) and are almost big enough to stir-fry but not quite.

Tonight, we will enjoy the first produce of the garden (Micro-greens?  Nano-greens is more like it) on slices of buttered bread.  Such delicacies are one of the main reasons I enjoy keeping a garden.