Introduction
This primer is designed to give the prospective chestnut
grower basic background information about what is involved in successful
chestnut production in Iowa. It will outline the minimum requirements of
soil, climate, equipment, labor, and capital. Rural landowners should be
able to use this information to help decide whether chestnut growing is
feasible and desirable for them. This primer is not intended as a complete
manual for chestnut production. Members of the Southeast Iowa Nut Growers
Cooperative are available for helping prospective and novice growers with
specific questions or problems. This primer was made possible by a grant
from the Iowa Department of Agriculture and Land Stewardship, and with
assistance from the Practical Farmers of Iowa.
 Background
Information
Chestnuts are trees or shrubs in the
genus Castanea, and are in the same family as oaks and beeches.
They are not related to horse chestnuts, (whose nuts are poisonous) or to
water chestnuts. There are four species of commercial importance. The
American chestnut of the eastern United States was once the most important
species of tree in North America (Figure 1). They are the hardiest of all
chestnuts. They can withstand temperatures as low as
-50°F (zone
3). The American chestnuts were practically eliminated by the fungal
disease called chestnut blight, between about 1910 and 1950. The nuts of
American chestnuts are high quality and very sweet, but they are too small
to be considered commercially important. The trees are so susceptible to
the chestnut blight disease they are not feasible to grow commercially.
The European and Japanese chestnuts are
the most common chestnuts in international commerce. Their nut size is
very large, but their quality and flavor are the poorest of all chestnut
species. The European chestnut trees usually have little or no resistance
to the chestnut blight. Japanese chestnuts usually have some degree of
blight resistance. Both of these species are marginally hardy in zone 5.
The Chinese chestnut is the most variable
of all the species. The growth form may range from a low, spreading shrub
to a tall timber tree. The nut size ranges from as tiny as the Americans
to larger than the largest Japanese and Europeans. The nut flavor ranges
from as good as the Americans to as poor as the Japanese and European
chestnuts, and is not necessarily related to the nut size. The other
measures of nut quality such as appearance, peelability, kernel texture,
and storage quality, are almost always superior in the Chinese chestnut
when compared to the Japanese and Europeans. This species is variable in
hardiness. Chinese chestnut from southern sources might not survive even
one mild winter in southern Iowa. The hardiest can survive -40°F
with no damage. A strain of Chinese x American hybrids from Canton,
Minnesota is hardy to -50°F.
The Chinese chestnut is the only species
with enough resistance to chestnut blight to be commercially viable in the
Midwest. Many are completely immune, and most are at least very resistant
to the blight. Only a small percentage are susceptible. For the rest of
this discussion, when we refer to chestnuts we are talking about Chinese
chestnuts or hybrids with Chinese.
Chestnuts in World Commerce
The history of chestnuts as a commercial
crop goes back at least 5,000 years (corn only goes back 1,000 years). In
all that history the supply has never been able to meet the demand.
Chestnuts rank 3rd (among nuts) in the world, behind only
coconuts and peanuts. Demand for chestnuts exceeds the demand for almonds
and all types of walnuts, combined. Chestnuts are the 3rd most
important food crop in China, behind only rice and wheat, and ahead of
corn. All this suggests chestnuts are neither a fad nor a niche crop.
The U.S. imports over 40 million pounds of
chestnuts per year. Less than a million pounds are produced
domestically. Most of the imports are livestock-feed grade nuts from
Italy. Besides being poor quality to begin with, most of these nuts are
moldy or even rotten by the time they arrive. Korea will probably begin
importing large amounts of large but equally poor quality nuts within the
next few years.
It is reasonable to conclude high quality,
good tasting, and locally grown chestnuts could out-compete and displace
some of the poor quality but expensive imports. Growers in Southeast Iowa
have been receiving between $2 and $4 per pound over the last two years
(2000 and 2001), and had no trouble selling all of the crop locally. A
surge in interest in chestnuts has resulted in many new plantings in the
last 20 years. Even so, at the rate new chestnut plantings are going in,
it will take between 80 and 100 years before there are enough acres to
meet the demand in the U.S. as it exists today, (and demand has
about doubled in the last 10 years). In short:
--Demand for chestnuts is high, genuine, and
long-term.
--There is no foreseeable danger of overproduction
within at least the next 100 years.
--Prices paid for chestnuts have always been high,
and are going higher.
--We can grow them in Iowa (and we are).
Chestnuts as a Cash Crop
Chestnuts have a lot of advantages as a cash
crop for Iowa. Unlike most other nut crops, chestnuts tend to be heavy
annual bearers (many other nut trees bear a good crop every other year, or
even less). Worldwide, chestnut production tends to range between 1000 to
9000 lbs per acre. We are conservatively estimating production in Iowa to
reach between 1000 and 2000 lbs per acre at maturity (it will probably end
up higher). Net profits should range from $1000 to $6000 per acre
annually. Chestnuts can be grown on land which would be marginal for
other crops. A few other advantages:
--Chestnuts could easily be grown without chemical
fertilizers or pesticides.
--They can be grown and harvested without expensive
or specialized equipment.
--Chestnuts are long lived (1000+ years) so they only
need to be planted once.
--Soil erosion from a well-managed chestnut planting
should be at least 1000 times lower than from
no-tilled row crops.
--Chestnuts can be profitable even on a small scale.
A farm family could earn a very good living on as few as 10-40 acres.
--Chestnuts have great potential for strengthening or
even rebuilding rural communities.
There are a few serious disadvantages to
chestnuts as a cash crop:
--Chestnuts require a considerable investment in
capital and labor up-front, just to get them established, then there is no
significant return for at least 5-6 years (average about 7-8).
--Marketing requires some effort and ability (unless
you market through a cooperative). You can’t just take them down to the
local elevator.
--The crop is perishable. It must be kept form
drying out, and should be refrigerated until sold.
--There is a serious lack of experience and expertise
on the subject of chestnut growing, both in Iowa and nationwide (the
Southeast Iowa Nut Growers can provide some assistance here).
This primer is intended to help prospective
chestnut growers weigh the advantages and disadvantages, and decide
whether chestnuts will be a good choice for them.
Successful Chestnut Growing—What Does it Take?
Before going any further it should be
stated that nothing in this primer should be interpreted as a
recommendation to plant a large monoculture of chestnuts. Large
monocultures of anything (including corn and soybeans) are invitations to
pest and disease. They usually require a great investment in energy,
labor, and chemicals to maintain, and will probably fail in the end
anyway. There are a number of other high-value tree crops which could be
interplanted with chestnuts to attain the high level of biodiversity
needed to control pests and diseases naturally. Information about other
crop trees and how they can be incorporated into a chestnut planting is
available from the Southeast Iowa Nut Growers (see Appendix).
The first important step in establishing a
chestnut planting (once you’ve decided to do it) is careful planning.
This process should start at least 6 months to a year before any work is
started. Unless you are already a tree farmer, or at least have a lot of
experience and a track record of success in tree planting (two or
three trees in your yard doesn’t count), you should get help with this
step. Your local DNR district forester should be one of the most helpful
persons with this step. Besides being able to help you put a tree
planting plan down on paper, foresters have a lot of expertise in site
selection, site preparation, tree planting, post-planting care and
maintenance, ground cover, weed control, and protection form
deer/rabbit/mouse damage. Your local NRCS office can be very helpful in
evaluating a potential site for suitable soil types. They may also be
able to provide some cost sharing for tree planting in some cases. For
selection of species, strains, and varieties of chestnut seed, nursery
stock, and related supplies, consult the information sources listed in the
Appendix. Also listed in the Appendix is a list of organizations which
could be very helpful, and their membership fees could be some of the best
investments you ever make.
At a minimum, items to be addressed in your
planting plan should include:
--Site selection
--Site preparation
--Between-row ground cover
--Between-row mowing (frequency and height)
--Spacing between and within rows
--Selection of seed or nursery stock
--Planting (trees and ground cover)
--Weed control
--Control of deer, rabbit, and mouse damage
--Prevention of damage from fire and herbicide drift
--Management of soil pH (in areas with high pH soils)
This plan should be down on paper, referred
to frequently, and followed. It should be flexible, and should be amended
as necessary. Unanticipated problems will crop up, and will need to be
addressed, but not by ignoring or discarding the plan.
Site Selection
Site selection is the first, and possibly the
most important step in the planning process. You need to decide if
chestnuts can be grown in your area, and on your soil. In general, if you
live south of a line from about Maquoketa, through Cedar Rapids and Ames,
to Council Bluffs, then you are probably within the climate range where
pure Chinese chestnuts can be grown (as long as they are from northern,
hardy sources). The closer you get to that line, the more marginal they
become. North of that line, but east of Interstate 35 (roughly the
Northeast quarter of the state), the hybrid chestnuts developed at
Badgersett Research Farm at Canton, Minnesota are a viable alternative to
the pure Chinese chestnuts. Their nut size is a little smaller, but still
large enough for commercial purposes. They have blight resistance, and
are hardy to about –50 F. West of I 35, in the Northwest corner of the
state, the Badgersett hybrids could still be grown, but with more
difficulty. In that area they would need a windbreak to the north and
west, and careful management of soil pH.
After climate, the next most important site
consideration is soil drainage. Chestnuts require a well-drained soil.
They will not tolerate poor drainage. They will tolerate dry, sandy or
gravelly soils. If you are not intimately familiar with the soil drainage
characteristics of a particular site, you should consult the NRCS or your
district forester.
Soil pH is another important
consideration for site selection. Chestnuts grow best in a pH range
between 5.5 and 6.5. Most soils in Eastern Iowa are within that range
naturally. The farther west you go, the higher the ph. West of Des Moines
the soils are often 7.0 or higher. Calcarious soils in Northeast Iowa
often have this problem too. Chestnuts can be grown in these areas, but
the soil pH has to be amended first, and managed thereafter.
Avoid frost pockets and areas with danger
from fire and herbicide drift from adjacent fields, if possible. In
short, the three most important considerations for site selection are:
climate, soil drainage, and soil pH. The only one you can change
practically is pH.
Site Preparation
Before chestnuts or any other trees are
planted, the planting site should be prepared to receive them. If
undesirable vegetation exists on the site it should be controlled or
eliminated. The worst plants to have on a tree-planting site are smooth
brome, orchard grass, tall fescue, and alfalfa (and in that order). If any
of these are present the entire area should be completely killed and
reseeded to more compatible vegetation. The choice of seeding mix will
depend on the planned mowing regimen. If the plan calls for frequent close
mowing between tree rows (as in a lawn) then a good seed mix would be
bluegrass and white clover (low, runner type). If the plan calls for
mowing only 2 – 4 times per year then a better mix would be timothy and
red clover and/or alsike clover. If possible, this ground cover should be
established before the first tree is planted.
Selecting Planting Material
As discussed earlier, hardy Chinese
chestnuts (or hybrids with Chinese) from northern sources are the only
chestnuts that should be considered for commercial planting in Iowa. They
should only come from reputable sources, and they should have superior
genetics for commercial purposes: hardiness, blight resistance, nut size
and quality, and productivity. There are a lot of nurseries out there
eager to sell you chestnuts with mediocre or poor genetics. Avoid them.
Consult the Appendix for good sources.
The next step is to choose between seedlings or
grafted varieties. Grafted varieties give consistence in productivity,
quality and ripening time. They make orchard management easier. On the
other hand, grafted trees are much more expensive ($12 - $20 each or
more), are in short supply, and may have problems with delayed graft union
failure, resulting in the loss of the grafted variety. Delayed graft
union failure has long been a problem with grafted chestnuts, and has been
a major barrier in the development of the chestnut industry in the US. It
has been found the best way to reduce the incidence of graft union failure
is to graft varieties only on their own seedlings or siblings.
Seedlings are very
variable in nut quality, nut size, productivity, and ripening time. Since
each seedling ripens nuts at a different time it may be necessary to
harvest the whole orchard every day, or every other day, for a month or
more. A good compromise solution is to plant a large number of seedlings
from superior parents, cull heavily, select the best 5 or 10 individuals
once they begin bearing, and graft the remaining trees to those best 5 or
10 trees. Again, it would be important to graft those selections onto
their siblings to reduce graft union failure. (Anyone who can whittle a
stick with a pocketknife can learn to graft chestnut trees in about 15
minutes).
A very profitable planting
could be based entirely on seedlings rather than grafted trees. It would
be very important to start with the very best genetics, plant a lot more
than you want to end up with, and cull out the poor performers once they
begin bearing. For this type of planting you should probably space the
trees 5’ apart within the row to start.
In some cases direct seeding may be
successful as an economical alternative to planting nursery stock. Hazards
which will result in failure of direct seeding include seed drying out
(even a little), freezing, and being eaten (by mice, chipmunks, squirrels,
deer, and raccoons). If you wish to risk this technique then contact the
Southeast Iowa Nut Growers for detailed instructions on how to be
successful.
The best varieties for Southern Iowa
(either as grafted trees or as parents of seedling plantings) are:
“Eaton”, “Sleeping Giant”, “Mossbarger”, “Peach”, “Amy”, “Orrin”, and
“Gideon”. A newly discovered variety call “Qing” (pronounced “King” or “Ching”)
may be the best variety in existence, but has not yet been tested in Iowa.
Badgersett hybrids are the only viable choice for Northern Iowa. Some
varieties to avoid are: the Japanese x European hybrid variety “Colossal”
which is popular in California and Michigan (it produces big nuts but nut
quality, nut flavor, hardiness, and blight resistance are inadequate), and
the Dunstan Hybrids from Florida (they have not performed well this
far north). Refer to the appendix for specific nursery stock and seed
sources.
Planting, Spacing, and Thinning
Much is written elsewhere about tree
planting, and there is no need to repeat it all here. There are a few
points worth emphasizing: Nursery stock should be planted in the field at
the same depth it grew in the nursery. Planting too deep is the most
common fatal mistake in tree planting. Even one inch deeper than nursery
depth may be fatal to the chestnut seedling. The planting hole should be
large enough to accommodate the root system without bending or crowding
the roots. It is better to prune back the roots rather than to bend or
crowd them in the hole. Backfilled soil should be firmed around the roots
to eliminate air pockets, but without compacting the soil or mashing the
root system.
Chinese chestnuts have a mature height
and spread of 40’. This means your final orchard spacing should be 40’
between rows and 40’ within rows. It may take 20, 30, or even more years
for the trees to reach this size, so if you start out planting at this
spacing you will have a lot of empty, unproductive space for a lot of
years. A sensible alternative is to start out with a more dense spacing,
such as 20’X20’ (for trees which are to be grafted--a spacing of 5’X20’
would be better for trees which are to remain ungrafted). About the time
the trees begin bearing heavily at 10-12 years old they will have nearly
filled up the growing space in the planting. Later, as the trees begin to
crowd, every other row can be removed. After another 5 or 10 years every
other remaining tree can be removed, and the final 40’X40’ spacing will be
achieved.
Post Planting Care and Maintenance
Care and maintenance are very important
to the establishment of chestnuts, yet this is where the most failures
occur. More than half of all tree plantings done by non-professionals
fail. The number one reason for these failures is inadequate (or
non-existent) weed control. Very few trees will survive in a planting
without good weed control. The worst weeds are grasses, and the worst
grasses are brome, orchard, and tall fescue (and in that order). They
compete with trees for moisture, nutrients, and most of all for growing
space for roots between soil particles. Broadleaf weeds compete with
trees mainly for sunlight, and then only when they overtop small trees.
Weeds need to be controlled at least within 3’ of trees during
establishment. Weed control can be accomplished in several ways. The
very best way is to use a combination of high quality landscape fabric (a
6’X6’ square for each tree, with the tree growing out a slit in the middle
of the square) together with a light topping of mulch over the fabric
(Figure 2). This method is expensive and labor intensive up front, but if
properly done and maintained, it needs to be applied only once. This will
save time and money in the long run.
The fastest, easiest, and cheapest weed
control is with herbicides. Herbicides should only be applied by
professionals with experience applying them on trees. They need to be
reapplied every year for at least 5 years. If enough herbicide is used to
control the weeds, the trees will be hurt at least a little. If the dose
used is small enough to prevent hurting the trees, then the weeds will
hurt or kill the trees. Success requires a careful balance.
Mowing at least 2-4 times per year should
be done to control the vegetation between tree rows, but mowing by itself
is not enough to provide adequate weed control.
Many people attempt weed control by
mulching alone. Sometimes it even works. In most cases it requires so
much material and labor (64 pickup loads per acre) it just isn’t practical
on any scale larger than a backyard. If done improperly or with the wrong
materials, mulch can cause some severe problems, including total failure.
Another important part of care and maintenance is protecting small trees
from damage from deer, rabbits, and mice. In areas where deer are a
potential problem (all parts of Iowa, including in town), 5’ tree
shelters, either fine mesh or solid-vented, offer the most reliable
protection. Avoid using solid unvented shelters on chestnuts. That will
kill them. An economical alternative to tree shelters is the use of deer
repellants. There are a number of fairly effective and long lasting
brands on the market. Some can even be used in organic applications. All
need to be applied 3-6 times per year (for the long-lasting ones). An
effective home made deer repellant spray can be made by mixing one dozen
eggs with 5 gallons of water. The mixture must be strained through a
window screen before it is put into the sprayer or the sprayer will plug
up. This mixture needs to be reapplied every 2-3 weeks, year-round.
In some areas rabbits will cause severe
damage to tree plantings. If rabbits are a potential problem then an
inexpensive plastic mesh tree shelter 18” tall should be applied to each
tree, assuming you don’t have 5’ shelters on them already (Figure 3).
Repellants do not work on rabbits. The rabbit proof shelters cost
about 25 cents each. See the Appendix for sources of shelters and
repellants.
In some years mouse populations
explode. In the winter, the starving mice often girdle small trees below
the soil line. The best way to prevent this is to eliminate mouse habitat
within the planting by keeping the vegetation between tree rows mowed
short (2 – 3 Inches), especially going into the fall.
Protection from fire and herbicide drift
may be an important consideration in some cases. A good relationship with
the neighbor is often the best protection from these hazards. Otherwise a
good firebreak at least 20 – 30 feet wide is usually adequate for fire
protection. A row of tall, dense shrubs such as honeysuckle or highbush
cranberry can be used as a barrier to block and absorb herbicide vapor
drift.
A great many insects will feed on the
leaves of young chestnuts, but they very seldom are serious enough to need
control. Occasionally caterpillars can become numerous enough a treatment
with Bt is justified. In very sandy areas of eastern Iowa, especially
around Davenport and Muscatine, Japanese beetles may become a serious
problem, and will need to be treated with a insecticide.
If chestnuts are well planted and cared
for on a good site, within 5 or 6 years they will be large enough to hold
their own against deer, rabbits, mice, and weeds.
Potential Disease and Pest Problems
The fungal disease called Chestnut blight
is the most serious threat to Chestnut trees. Most, if not all grafted
varieties of Chinese chestnuts are resistant or immune to the blight.
About 20% of Chinese seedlings will be susceptible. No other species of
Chestnut has as high a level of blight resistance, but if you are planting
seed or seedlings you need to factor in a loss from blight.
Phytophthora is another fungal disease
that can devastate chestnuts planted on poorly drained soil. There is no
treatment. The only practical prevention is to plant chestnuts on
well-drained soil.
Chestnuts are susceptible to oak wilt disease. It is not known to transmit
through root grafts as it does in red oaks. This disease is not considered
a serious problem for chestnuts. The best prevention is to avoid pruning,
or anything else that will cause sap bleeding from open wounds, between
April and July. The sap attracts the beetles that carry the fungus.
Several other diseases occasionally damage or kill chestnut trees, but
none are considered a serious problem.
Chestnut weevils (two species) are
potentially the most serious insect pests for chestnuts in Iowa (Figure
4). Adult weevils lay eggs in developing nuts. The larvae burrow through
the kernel and ruin it. In some areas of Southeastern United States the
infestation rate approaches 100%. Control with insecticides is possible
but difficult. The best control is achieved by allowing chickens to
free-range in the orchard, and allow hogs to clean up any nuts missed
during harvest. This effectively breaks the weevil’s life cycle.
There are no populations of chestnut
weevils known to be within a few hundred miles of Iowa (Indiana is the
closest). There is no telling when they will even get here, but they
probably will arrive someday.
The chestnut gall wasp, which was
introduced from Asia, causes severe damage to chestnut trees in Georgia
and Alabama. The insect is slowly moving north and west, but will probably
never reach Iowa. It is a sub-tropical species and cannot survive harsh
winters.
Gypsy moths will probably spread across
Iowa someday. In severe infestations the caterpillars can defoliate whole
forests, but trees are seldom killed. The caterpillars can be controlled
with Bt.
Japanese beetles may cause serious damage
in very sandy areas in Eastern Iowa. An application of insecticide may be
the only practical treatment.
Once chestnuts begin bearing the nuts
will be very attractive to mice, chipmunks, squirrels, turkeys, and deer.
Prompt, daily harvesting may be the only way to insure you get your share.
A program of population control for the squirrels may also be necessary.
In general, chestnut diseases and pest
problems are fewer in number, more manageable, and less serious than for
most other crops grown in Iowa.
Pruning and Spraying
Chestnuts are unlike apples, cherries, peaches, and most other tree crops
in that they do not need an annual pruning program. Chestnuts need to be
pruned to establish a clear trunk up to about 8 feet to facilitate access
under the tree for nut harvest (Figure 5). This pruning is done during the
initial establishment of the planting, within 5 to 10 years. Try not to
prune off more than ¼ to 1/3 of the top in any one year, or the tree may
become stunted. Avoid pruning from April through July if possible. Limbs
should be pruned when they reach about 1” in diameter. Do not prune limbs
flush with the trunk, but instead cut beyond the “branch collar,” the
swelling at the base of the branch (Figure 6). Once the 8’ clear trunk is
achieved, the chestnuts need no more pruning.
Chestnuts can easily be grown without
spraying for disease or insect control, especially if chickens and hogs
are used to control weevils.
Mowing
Mowing between tree rows will continue to
be important even as the trees mature. Mowing should be done at least 2 –
4 times per year. The most critical mowing is done early to mid September
just before nut harvest. Trying to harvest chestnuts hidden in tall grass
is impractical if not impossible. It may be feasible to substitute
rotational grazing by cattle, sheep, or goats once the chestnuts are
mature (15 – 20 years).
Fertilization
Chestnuts can grow and bear profitable
crops of nuts without ever being fertilized, but to get the very highest
yields a program of regular fertilization will be necessary. Organic
fertilizers including finished compost can be used instead of chemicals.
Beware of compost made form city yard waste. It often contains substances
toxic to trees. If you want to use “city compost” then take a
representative sample, place it in a small container, and try growing
something like pinto beans in it for a few weeks. If the beans do well
the compost is probably all right. If they fail to germinate of die
later, then don’t use that compost on your trees. Organic fertilizers
form commercial sources should be safe. The higher cost can be easily
offset by the higher value (double or triple) for certified organic
chestnuts. If chemical fertilizers are used then regular soil tests should
determine the quantity and type. Regardless of what kind of fertilizer is
used, it should be applied in spring, and never any later than early June.
Fertilizer applied later will result in tender late season growth which
will be subject to winter damage. Fertilizer (except for finished compost)
should not be applied to trees in the year of their planting, but may be
started in the 2nd year. A good fertilization program should
maximize the trees’ growth rate, health, vigor, nut production, and
resistance to disease, insects, cold, and drought.
Management of soil pH
In areas with a naturally
high soil pH such as Western Iowa and limestone-soil areas in Northeast
Iowa, successful chestnut growing may require careful management to bring
soil pH down at least to 6.5. On a small scale (a couple of acres or
less) this could be accomplished by incorporating partially decomposed
sawdust or wood chips (fresh sawdust may be toxic to trees). On a larger
scale chemical fertilizers may be the only practical alternative.
Fertilizers are so good at acidifying soil farmers are continually adding
lime to bring their pH’s back up. Ammonium sulfate is probably the best
choice of chemical fertilizers for acidifying soil. Avoid aluminum
sulfate. Soil tests should be done to determine how much and how often to
apply the fertilizer.
Harvesting, Handling, and Marketing Chestnuts
Most seedling chestnuts with good
genetics, if well planted and cared for on a good site, should start
bearing when they reach 6’-8’ tall (about 5 or 6 years). Grafted trees
will bear within 2 – 3 years. You should expect marketable quantities (100
pounds per acre or more) within 7 or 8 years, and a mature level of
production (1,000 pounds per acre or more) some time between 10 and 20
years (depending on site, management, and the varieties being grown).
Starting in mid-September, the spiny burs which enclose the chestnuts (and
protect them from squirrels) will begin to open up (Figure 7). Most of
the nuts from any one tree will fall to the ground over a period of 2 – 4
days. If you are growing seedlings, that 2 – 4 day period will be
different for every tree, and may stretch from early September to late
October. About 15% - 30% of nuts will drop before or after the 2 – 4 day
peak. A few nuts get stuck in the burs and drop with the burs a week or so
after the main nut harvest for that tree. If grafted trees are being
grown, all the trees from any one variety will ripen their nuts at the
same time. When the nuts are falling, chestnuts must be harvested at least
every other day, and every day if the weather is warm and dry. Besides the
fact that you are racing against the squirrels, if chestnuts lay on the
ground for more than two days, they will dry out and be ruined.
Around the world, most chestnuts are
harvested from the ground by hand. No mechanical harvesting equipment
designed for chestnuts exists yet (though this will probably change). Some
alternatives to hand harvest include raking with a plastic leaf rake and
scooping with a shovel; deploying tarps or netting under trees just before
nut-fall; using a lawn sweeper; and the Bag-a-nut machine (see appendix).
All of these methods have been used with varying degrees of success. All
these have strong points and weaknesses.
Post Harvest Handling
After chestnuts are harvested they need
to be separated from any leaves, twigs, burs or rocks, and cleaned of any
dirt (hosing them off with water will work for this). If washed with water
the nuts will need to be thoroughly drained before bagging. The nuts
should be sealed in 1 – 2 gallon Ziploc bags (or something similar) with
no more than 10 pounds/bag. They need to be kept cool. Refrigeration is
recommended, but not absolutely necessary. The most important point is to
never let the chestnuts dry out, not even a little bit. If you see
moisture condensing on the inside of the plastic bag then the nuts are too
moist. Open the bags and set them out a room temperature for an hour or
so, then reseal. Repeat if necessary.
If chestnuts are to be stored more than a
few weeks they should be in perforated plastic bags (such as what apples
come in) and refrigerated at 80% - 90% humidity. Chestnuts can be stored
indefinitely at a temperature between 28°F
and 30°F. They still need to be
kept from drying.
Marketing
The market for chestnuts is huge and
growing. One of the largest chestnut growers in North America claims he
gets calls every day of the year from people wanting anywhere from one to
one hundred semi loads of chestnuts. In his best year he produced about
one semi load. An ad on the internet is offering to buy Chinese chestnuts
grown in North America, but the minimum quantity is 22,000 pounds. Even
with this much demand you still cannot take this crop down to the local
grain elevator to sell it. Unless you can market them through a
cooperative you will have to sell chestnuts wholesale to retailers such as
grocery stores, or sell directly to consumers such as at a farmers’
market. Warehouse-type grocery stores with large produce sections are
good places to sell nuts. Larger cities such as Des Moines, Cedar Rapids,
Iowa City and other cities with large ethnic communities are usually much
better market areas than small towns. Most people from Europe and Asia
know and love chestnuts, and will eat a lot of them if they can get good
ones (they will not usually bother with the poor quality imports). Most
Americans need to be educated about how to use and enjoy chestnuts.
Conclusion
It is hoped this primer will help you
make wise decisions about whether and how to grow chestnuts. If any of
this information is unclear or inadequate you may contact Tom Wahl of the
Southeast Iowa Nut Growers at:
|
Red Fern Farm |
phone: 1(319)729-5905 |
| 13882
I Ave |
|
|
Wapello, IA 52653 |
email: redfernfarm@lisco.com |
|
Information is also available at the website |
www.redfernfarm.com . |
|
Figure 8. Chestnut parts:
|
| a. Leaf |
| b.
Twig; |
| c.
Male catkin |
| d.
Bisexual catkin with female flowers |
| e.
Nut . |
Appendix
Sources of Seed/Nursery
Stock
|
Southeast Iowa Nut Growers |
|
C/O Tom Wahl |
|
13882 “I” Ave |
|
Wapello,
IA 52653 |
|
