Archive for April, 2011

How to do whip-and-tongue grafting (benchgrafting)

April 24, 2011

My mom snapped some pictures while I was doing some bench grafts up in Five Islands last visit, so I thought I’d post a photo-lesson on how to do this type of grafts. I’m hardly an expert at this, having just learned last spring, but all seven or so grafts that I made at the MOFGA class last spring took, and then I taught Joshua and Kelsey to do it, and most of the grafts they made took as well, despite the scionwood getting pretty old, so I figure it can’t be that difficult – though it seems that having done a lot of whittling in childhood helps. Some discussion after the photos.

Here’s the scionwood (left), and Budakovski 118 rootstock (right). Normally I use seedling Antonovka rootstock, but Fedco was sold out. B118 makes a tree nearly as large as seedling rootstock, and supposedly comes into bearing a bit sooner than Antonovka. The pieces should be about the same diameter, but it’s not a big deal if the scion is smaller than the rootstock.

Make the first cut at a medium-steep diagonal to the axis of the piece, so as to form a planar face in the neighborhood of 3/4″ or 1″ long, depending on the diameter of the piece. You want to cut it with the unbeveled side of the knife toward the piece you’re keeping, and you want to do it in one smooth motion, rather than whittling away at it, since whittling inevitably leaves a faceted surface rather than a smooth plane. Here’s where my technique is hampered by not having a left handed grafting knife; I basically grip the scion with one hand and freehand the first cut, with the knife pointing away from me:

Getting the first cut smooth, planar, and at the right angle takes some practice; right-handed folks can use a slick technique where the knife is held by the fingers of the right hand (palm down), with the blade over the thumb and pointing back toward the body. The twig is placed between the thumb and the blade and pulled smoothly away from the body, with the angle and pressure on the knife setting the cut at the correct angle. The exact angle doesn’t matter so much as planarity and smoothness. In all cases, avoid touching the cut edges with your fingers (or anything other than a clean knife). Here are the mating surfaces (B118 rootstock has a purplish color, like a redfield):

Place the cuts so they don’t slice through any buds, and flip out any buds that are too close to the graft union and threaten to burst through the wrapping tape prematurely. The next step is to make the axial cuts to form the ‘tongues’ that hold the graft together. This is done with the flat edge of the knife toward the pointy end of the diagonal cut, symmetric across the cut face, and slightly more than half way from the base of the diagonal cut to the tip – I usually make the axial cut at about the pointy end of the central pith, and go until it feels like the twig is about to start splitting ahead of the knife, but hasn’t actually split yet. No material is removed when making this cut, it’s basically just a small controlled split in the twig. It takes a bit of practice to get a clean tongue that’s in the right place and not smashed up:

Once both halves of the graft have both cuts, just push the mating parts together by pressing the diagonal faces together and sliding them axially toward one another until the two tongues engage one another and jam together. If the angles of the diagonal cuts are consistent, and the axial cuts are in the right place, the pieces will fit together so the splice is barely perceptible:

My experience last year is that the fit doesn’t have to be this good to get a strong graft. And if one piece is significantly smaller than the other, don’t split the difference – pick the side where the fit is nicest, and justify the scion over to line up with the rootstock on that side. Here’s one where the axial cuts weren’t far enough toward the tip, so the two pieces go a bit too far past one another – but I’m pretty sure it will take anyway; there’s plenty of good contact between the two pieces:

The graft should be mechanically self-supporting at this point, but it needs to be protected and sealed so it won’t dry out before the union heals together. I use parafilm tape, basically a stretchy and self-adherent but not sticky LDPE film that’s familiar to folks who’ve worked in chemistry labs – Fedco Organic Grower’s Supply sells it. It isn’t UV stable, so it disintegrates at about the right time, a couple months after it’s put out. I start at the bottom (so it sheds water) and stretch it pretty tight as I go (so the faces are pressed tightly together):

If there are any buds in the way of the wrapping, flick them out with the knife so they don’t burst through the tape. Finally, cut the scion off leaving two good buds above the union. One is all you need, but two is good in case one is a dud. More than two and the graft union will have a hard time supporting all that vigorous activity above.

The cut surface at the tip of the scion should be protected with a dab of Tree-Kote or wrapped in parafilm to prevent it drying out. I left the grafted trees in an unheated garage in a bucket of moist sawdust for a couple weeks, until they started showing signs of life up top, then planted them out, though I gather it’s fine to plant them out directly. If the graft takes, the buds will take off and put on at least a foot or two of growth the first summer. Once it’s clear they’ve taken, the weaker of the two buds should be clipped off, as should any buds on the rootstock.

That’s basically all there is to it. Here’s some background info:

Common apple varieties can’t be grown from seed, since the seeds taken from any given type of apple will not produce that same variety of apple if they are sprouted and grown up to maturity. So instead, a little twig or ‘scion’ is taken from the desired type of apple and spliced or ‘grafted’ onto the stem of a small apple tree of a different variety (the ‘rootstock’) , and it grows up to become a full-sized tree with the fruiting properties of the tree from which the scion was taken. While the rootstock can just be a sprouted apple seed (‘seedling rootstock’), in which case it will grow into a robust full-sized tree, in modern practice it is common to graft onto a special rootstock that gives a greater or lesser degree of ‘dwarfing’ character, which means that the tree will not grow as large, but it will come into bearing sooner (though it will be less healthy and be more likely to die after a number of years). Rootstocks can also confer other desirable traits, such as disease resistance. Rootstocks have been carefully selected by various breeding programs, and they themselves must be propagated by special techniques. Dwarfing rootstock is very common in commercial orchards, where economics dictates that the plot must fruit relatively quickly to recoup the capital investment of planting.

So, grafting is necessary to propagate the apple varieties we’re all familiar with. But why not just let a commercial nursery do the work, and buy trees that have already been grafted? For one thing, it’s a lot cheaper; scionwood is free if you have access to a tree of the desired variety to collect from during the March pruning (and the MOFGA scionwood swap is a great source as well), and rootstocks cost from under $1 in volume to maybe $3 for small quantities, while a good quality year-old grafted tree runs over $20 from Fedco. Also, given the dozens of rootstock varieties and hundreds of apple varieties available, it’s simply not practical for nurseries to offer every apple variety on every rootstock, so if the orchardist has a particular need for a particular combination of apple variety and rootstock, custom grafting can be the only way to get it.

The whip-and-tongue ‘benchgraft’ is one common way to splice a scion onto a rootstock. It’s called ‘whip-and-tongue’ because of the shape of the joint that’s made, and it’s called ‘benchgrafting’ because it’s typically done indoors, at the orchardist’s convenience, sometime in mid spring. Typically you’ll start out with a handful of scionwood, and one or more bare-root rootstocks, which will be around 18″ long and somewhere around the diameter of a pencil or less. It’s important to keep the scions labeled with tape or in a labeled bag, since once you lose track of what type they are, they’re pretty much useless. And its important that the scionwood be essentially dormant (i.e. store it in the fridge, tightly wrapped in plastic with moist paper towel or other source of moisture), and its good if the rootstock is somewhat less dormant (I left mine in a 50F basement for a week or so, and the buds had just started to show new growth). The basic idea is to create a splice between the scion and the rootstock that provides a large area for the cambium of the two pieces to touch, and at the same time provides for the two pieces to be held physically together for long enough that they grow together and heal into a strong graft union.

A grafting knife is basically just a single-blade pocket knife with an edge that’s only ground on one side. I bought one (Victorinox) for $20 or so at the MOFGA class. It’s right-handed, and I haven’t bothered to regrind it left-handed, so my technique is a bit awkward, but it seems to work fine. Maybe next year I’ll spring for a nice left handed grafting knife, though the only ones I see readily available online are fancy German ones that cost almost $100.

Advertisements

Alternative energy then and now

April 22, 2011

I was poking around upstairs in my grandparents’ barn some time ago and found a tattered paperback called “Handbook of Homemade Power”, put out by the Mother Earth News in 1974 (two years before I was born). I suspect it may have come from Vin Strout, an old time Mainer and incurable tinkerer who was our neighbor and good friend growing up. The book appears to be basically reprints of magazine articles from the time, and it’s separated into chapters as follows: heating with wood, water power, wind energy, solar energy, methane biogas. But what struck me about the book was how far things have come in the nearly 40 years since that first energy crisis.

When my parents and countless others of that generation went ‘back to the land’ in the 70s, renewable energy technology was just starting to be pieced together by tinkerers, and a lot of pre-modern stuff was basically pulled out of barns and put back into service from relatively recent obsolescence at the dawn of the petroleum age. The chapter on wood heat talks about antique wood ranges, and describes the various stoves that can be built with 55 gallon drums and the like. In the house I grew up in we cooked (in the winter) on an old Glenwood C, a wood-fired range from the 1920s, and heated with a Riteway, an airtight stove of plate steel construction with boxy 1970s styling – e.g. it was just a rectangular sheetmetal box. The Glenwood heated up fast, looked great, and my mom could bake with it pretty well, but it leaked like a sieve and so couldn’t hold a fire worth beans. The Riteway had huge capacity and held a fire really well, but it make creosote like crazy, and I gather from the internets that the company has gone out of business. Nowadays my folks use an airtight Heartland wood range for both primary heat and cooking, and it seems to do both pretty well. More generally, a huge variety of woodstoves are available these days, ranging from spartan-but-functional welded steel to classy cast iron, with and without catalytic converters.

The chapter on water power gets off to a reasonable start, describing how to figure out how much energy is in a stream, and the various types of small dams that can be built. But it spends a fair amount of time on inefficient old-fashioned wheel designs, and stops well short of describing designs that could actually produce useful electricity – though there is an article about a guy who used water power to build a giant rock tumbler. But generally, small-scale hydropower is such a rare and special site that its primary function is to generate envy in readers with more normal sites.

The wind chapter has a bunch of articles on homebuilt designs that look like early, crude versions of the Hugh Piggott homebrew design, plus an article on scrounging 1930s commercial windplants from the countryside (this was a big part of the wind revival in the 1970s; I have an old book by a guy named Michael Hackleman describing in detail how to find and rebuild these units), and a neat in-depth interview of Marcellus Jacobs, a pioneer of wind-electric equipment in the 1930s. But the homebuilt designs are hampered by the use of wound-field auto alternators, with their low efficiency and requirement for 12V power to energize the field windings. The advent of economical Nedodymium Iron Boron magnets has made homebrew (and commercial) small turbine design much easier, though it remains the case that fabricating an efficient, reliable small wind turbine is beyond the realistic scope for all but the most talented of homebrew tinkerers.

Solar is probably the area where the most profound progress has been made. The solar chapter in the Mother Earth book talks about passive solar house design, thermal storage, homebrew thermosyphon water heaters, and parabolic solar cookers made out of cardboard, but there’s not even a mention of solar PV, which back then was too expensive for anything but satellites. But today it’s possible to buy PV modules retail for about $2 per watt, which makes solar a pretty reasonable option. Without any special conservation measures, our apartment uses about 150 kWh of electricity per month, and NREL shows this area as receiving a bit over 4 hours per day of average sunlight on a latitude-tilt fixed array. So we could cover our electricity needs with a little over 1kW of PV. This is a significant advance over the clunky thermal demos of the 1970s. While I’m not super familiar with the options, I get the sense that solar thermal has come a long way since the 1970s as well, with refined flat plate designs and evacuated tube options available.

Biogas is the area I’m least familiar with; the articles from the 1970s describe crude contraptions with floating caps on open tanks for gas storage and the like. I’m not sure how much work has been done in this area in the ensuing years, but given the potency of methane as a greenhouse gas, I would think that small scale tinkering with methane production would best be left alone. Far better for the critters to leave their dung in the pasture, where it can decompose aerobically and feed the grass.

Anyway, my take-home message from comparing Mother Earth News’ Homemade Power Handbook to the 2011 state of the art is that things have come a long way, especially in solar but also in wind energy and wood heat. The quality and variety of commercial renewable energy products is much improved since the 1970s, and where the 1970s back-to-the-lander was left to his/her own devices to tinker up half-assed contraptions (vanishingly few of which are still in service), the modern homesteader who has a few thousand dollars to spend can readily make use of commercial technology to make a significant dent in their consumption of fossil energy.

Short video: cider making in western England

April 20, 2011

A gent name of Kevin Redpath showed up in the comments introducing a video about an orchard called Sheppy’s in western England, available at this link: http://vimeo.com/22562045

In pre-industrial times, “Farmers paid attention to producing good cider, because without it they could not attract a steady workforce. The ration for a strong man was 4-6 pints a day, and half again as much at harvest time.”

40 acres produce 700 tons of apples – that’s 35000 lb or about 875 bushels per acre. Named varieties include Coates Jersey, Yarllington Mill, Tremletts Bitter, Kingston Black.

There’s interesting video of a PTO-mount tree shaking contraption that vibrates the apples out of the trees, and a collector that sweeps them up off the ground. They also show a belt press in operation – it’s different than I imagined it, and doable with bike power I think, but we’ve got a pretty sweet setup at this point with our bike hydraulic platen press, so I doubt we’ll go there anytime soon.

Primary fermentation takes place in giant oak tanks. They also show an automatic counterpressure filler, where the cider flows in along the outer surface, and there’s a central stainless dip tube that seems to tell the machine when to stop the flow. That’s the opposite of our design, where the cider enters through the central tube, and the gas escapes at the perimeter.

Yup, NYT pimping chickens

April 5, 2011

Some days ago I ranted about the image accompanying a NYT article about young farmers. I knew that picture was too juicy for the Times to resist, and indeed here it is back again, right in the sidebar beside the latest on Fukushima:

A modest proposal: Appleosic Ethanol

April 1, 2011

It seems increasingly likely that the persistently high price of oil in the face of a historic economic downturn portends scarcity of liquid fuels in years to come, and efforts thus far to create and scale alternatives have fallen sadly short. Even today a quarter of the US maize crop is consumed to replace less than 10% of our petrol supplies, and we would be well advised to tread carefully in fermenting more, for fear of igniting further tortilla riots on our southern border, or – worse still – causing (for example) upheaval and conflagration in the Middle East. The much-touted ‘next-generation’ cellulosic ethanol is taking its time, with algae biofuels lagging still further behind. Electric vehicles are in the pipeline, but prices are projected to be painfully high. Clearly another solution is sorely needed.

Accordingly, I humbly offer the following proposal. A former president with credible experience in the matter of addiction recently diagnosed the nation with that sad affliction, and as it happens appleosic ethanol has long held a proud place in the pantheon of decadence and inebriation. For centuries distinguished gentlemen among our forefathers and hapless rogues alike gladdened their winter evenings with ethanol derived directly from the fruit of Eden, and in these challenging times a spirit with such a venerated and indeed spiritual provenance may be just what is required to keep our cherished motors running. World apple production is on the order of 60 million tonnes per annum, which when pressed can be expected to yield on the order of eleven billion gallons of fermentable cider. At an average alcohol content of six percent, this may be distilled to 675 million gallons of pure motor fuel, or sixteen million barrels. The US daily consumption of petroleum is only a trifle more than this, and the difference is all but made up by the aforementioned fermentation of maize.

Therefore, all that must be accomplished to solve our persistent and vexing energy challenges is to (1) increase the global production of apples by three hundred and sixty five times, and (2) appropriate the entire global apple crop for US use. The first task will be a matter of some effort, but from the current US production of 4.24 million tonnes per annum, at an average yield of 12 tonnes per acre, we can grow our share of the increase on about 200,000 square miles – an area scarcely larger than California. As that state is currently given over largely to the production of lettuces, cannabis, and similar non-nutritive stuffs, the conversion will be but a minor inconvenience, and a great many golf courses exist in that state with suitable infrastructure for irrigation already in place. The second task is a bit more daunting, but from long practice we are well-versed in the invasion of lands possessing raw materials necessary for transportation, and surely Messrs. Cheney and Rumsfeld could be pressed into service out of retirement in case of acute patriotic need. Once the necessary conquests have been put into effect, we will face the additional challenge of naval discipline aboard the great many tankers plying the seas with holds entirely filled with top-quality grog, but I trust that our professional servicemen can be expected to perform their duties with customary and utmost professionalism. Further, any resulting increase in shipwrecks will be of far less concern, pome-derived fuels being entirely miscible in seawater.

The evident utility of the foregoing proposal is such that I trust we will hear no more of the tiresome litany of ineffective solutions that are ever bandied about. Tell me not of increases in fleet average fuel economy, revitalization of rail networks, carbon taxation, and the charade of ‘telecommuting’, surely the largest windfall ever to land in the sweaty laps of the internet pornographers. Nay, for me let it be appleosic ethanol – for I see that a Dodge Dakota can go up to 12 miles per gallon on 85% ethanol. Why, at that rate of performance, my modest half-acre orchard could produce enough ethanol to make a one-mile round trip every single day of the year! Verily then, forward-looking citizens of good character will step up to further embrace the fateful choice our forebears made in Eden, and support appleosic ethanol – a fuel of truly biblical proportion.