In 2002 Tom Wahl wrote the Chestnut Primer. He updated it in 2017 and 2026. You can download a PDF copy of the new Iowa Chestnut Primer by clicking Iowa Chestnut Primer or read the primer below, but it will not have all the pictures.
The Iowa Chestnut Grower’s Primer
Written and Illustrated by Tom Wahl
Published 2002, Revised 2017 and 2026
3rd Edition
The Iowa Chestnut Growers’ Primer
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 Chestnut Growers of American and Northern Nut Growers Association 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. It was revised in 2017 and 2026 with the help of Kathy Dice.
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
–
Figure 1. Loggers standing at the bases of giant American chestnuts in the Appalachians. Photo courtesy of Forest History.
50°F. 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 and their hybrids collectively make up about 15% of the 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.
Chinese chestnuts make up about 85% of chestnuts in world commerce. Almost all are grown in China. Chinese chestnuts are 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
Figure 2: From left to right: American, Chinese, European, Japanese. Picture courtesy of https://patacf.org/
ranges from smaller than the Americans to larger than the largest Japanese and Europeans. The nut quality can be variable, but is usually quite high, and is not necessarily related to the nut size. The measures of nut quality such as flavor, appearance, peelability, kernel texture, and storage quality, are almost always superior in the Chinese chestnut when compared to the Japanese and Europeans (Figure 2). This species is variable in hardiness. Chinese chestnut trees from southern sources might not survive even one mild winter in southern Iowa. The hardiest can survive -40°F with no damage. Some Chinese x American hybrids can be so hardy as to survive
-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. In all that history the supply has never been able to meet the demand. Chestnuts are the #1 nut in the world in terms of demand, as long as you exclude coconuts and peanuts (neither of which are true nuts). Demand for chestnuts exceeds the demand for almonds and all types of walnuts, combined. Chestnuts are the 3rd most economically important food crop in China, behind only rice and wheat, and ahead of corn and soybeans. All this suggests chestnuts are neither a fad nor a niche crop.
Most of the chestnuts consumed in the US are imported from Italy, Korea, or China. Because of their perishability, most of these arrive in poor condition. This gives domestically grown chestnuts a powerful quality advantage.
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 $3.20/pound (for the smallest nuts) and up to $4.00/pound for good quality nuts at Prairie Grove Chestnut Growers in Columbus Junction, Iowa in 2024 (chestnuts must be delivered to coop before November 1st). Growers who direct market can receive up to $4 to $8, or more, per pound. 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 many decades before there are enough acres to meet the demand in the U.S. as it exists today. Demand has been doubling every 10 years at least since 1980. In short:
–Demand for chestnuts is high, genuine, and long-term.
–There is no foreseeable danger of overproduction for many decades.
–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 1,000 to 9,000 lbs per acre. We are conservatively estimating production in Iowa to reach between 3,000 and 4,000 lbs per acre at maturity (it will probably end up higher). Gross should range from $6,000 to $20,000 per acre annually at maturity. Chestnuts can be grown on land which would be marginal for other crops. A few other advantages:
–Chestnuts could be grown without chemical fertilizers or pesticides.
–They can be grown and harvested without expensive 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 1,000 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 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 years (average about 6 – 8 years to first significant harvest).
–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 harvested every day for a month, and then kept in refrigeration until sold.
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. Monocultures usually require a great investment in energy, labor, and chemicals to maintain, and will probably fail in the end. There are a number of other high-value tree crops which could be inter-planted 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 Northern Nut Growers Association and North American Fruit Explorers (NAFEX), see Appendix.
The first important step is finding out if you have a site suited for 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 Department of Natural Resources (DNR) district forester should be one of the most helpful persons with this process. 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 Natural Resources Conservation Services (NRCS) office can be very helpful in evaluating a potential site for suitable soil types.
Once you know your soil types, you can check them on Iowa Woodland Suitability table. Classes 3,4, 5 and 6 are generally suited to chestnuts. Class 7 soils can also work if irrigation and fertility management are used.
The NRCS may also be able to provide some cost sharing for tree planting in some cases. The University of Missouri Center for Agroforestry, www.centerforagroforestry.org, is a good source of information for growing chestnuts in the Midwest. For selection of species, strains, and varieties of chestnut seed, nursery stock, and related supplies, consult the information sources listed in the Appendix. Also 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:
Figure 3: Productive chestnut grove in southeast Iowa: Red Fern Farm 2020
–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, gopher, and mouse damage
–Prevention of damage from fire and herbicide drift
–Management of soil pH (in areas with high pH soils)
–Prevention and control of oak wilt
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, i n Iowa, 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), blight resistant hybrids between Chinese and American chestnuts are a viable alternative to the pure Chinese chestnuts. Care should be taken to select strains of hybrids that will produce nuts large enough for the commercial market. The most-cold hardy hybrids can tolerate -50°F.
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 your 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 and north of Des Moines the soils are often 7.0 or higher. Calcareous soils in Northeast Iowa often have this problem too. It is not practical to grow chestnuts in a highly calcareous soil. If your soil pH is between 6.5 and 7.5 you can probably amend it using elemental sulfur fertilizer. If your soil is above 8 in pH, it is probably not practical to amend it enough to grow chestnuts, and you should probably grow something else. Avoid frost pockets (low-lying areas) 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 reed canary, 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. A good seed mix would be bluegrass (20 lbs/ac) and Dutch white clover (2 lbs/ac). A better mix requiring less mowing (once it’s established) would be turf-type perennial rye grass (10 lbs/ac), and another 10 lbs/ac of fine-leaved fescue (such as creeping red fescue, Chewing’s fescue, or hard fescue, but NOT tall fescue, not even turf-type tall fescue) and Dutch white clover (2 lbs/ac). It is better, but not absolutely necessary, for the ground cover to be established before the first tree is planted.
Figure 4: Red Fern Farm: 27 year old seedling chestnut.
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 quality. Avoid them. Consult the Appendix C for good nursery sources. One choice you will have to make is whether to plant seedlings or grafted trees. My recommendation is to plant seedling trees with superior genetics. Grafted trees have multiple, serious problems, and at best, they perform poorly in Iowa. Seedling trees with superior genetics will produce nuts just as good (and often better) as the best grafted trees, but they will produce a lot more of them. Grafted trees always grow with lower vigor than seedlings, so even though they may begin bearing a year or two earlier than seedlings, the seedlings quickly catch up, and then surpass grafted trees in productivity – and that gap just keeps getting wider as time goes on. On average, grafted trees will grow with around 25% or 30% of the vigor of a seedling, and that is just counting the ones that survive! (See Figures 4 & 5) Grafted trees suffer from what it called “delayed graft union failure.” What this means is that the tree may appear to be healthy (but slow-growing) for 5 or 10 or even 15 y
Figure 5: Red Fern Farm: 27 year old grafted chestnut.
ears, and then die suddenly, for no apparent reason. In Iowa and other northern areas, this may happen to 50% to 70% of grafted trees, depending on the cultivar. And remember, the rest of the grafted trees will be growing with less than 1/3 of the vigor they should have. You cannot do this profitably! Grafted trees are good for one thing, and one thing only: they can produce superior seedlings. So, use grafted trees if you want to breed your own seedlings, but use superior seedlings for nut production.
As of 2026, the chestnut cultivars with a long track record of producing seedlings that grow up into profitable chestnut trees include ‘Qing’ (pronounced “ching”), ‘Gideon’, ‘Peach’, ‘Auburn Super’, and ‘Mossbarger’. There are probably many other good, but unproven parent trees as well. Some chestnuts to avoid include Japanese, European, and Japanese X European hybrids (especially the cultivar ‘Colossal’). The Dunstan hybrids should also be avoided in Iowa. They are marginally hardy in zone 6a and absolutely unsuited to zone 5 and farther north (all of Iowa). Chinese X American chestnut hybrids may be the only option for zone 4b, and may be the best to plant in zone 5a. Hybrids are more variable than pure Chinese, especially in terms of nut size and blight resistance. It is important to choose sources known to produce nuts of marketable size – 5 grams or larger.
Figure 6: Proper planting depth and technique for bare-root trees.
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 1/2 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 than to bend or crowd them in the hole. Back filled soil should be firmed around the roots to eliminate air pockets, but without compacting the soil or mashing the root system.
According to the literature, Chinese chestnuts have a mature height and spread of 40’. 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’. 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 so years, every other remaining tree can be removed, and the “final” 40’X40’ spacing will be achieved. Probably another thinning to 80’ X 80’ will need to happen some 40 to 60 years down the road, and a final thinning to 160’ X 160’ may be needed in 500 to 600 years.
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 reed canary, 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. Most weeds need to be controlled at least within a 3 foot diameter circle of trees during establishment. (100’ for brome grass!)
Figure 7: Landscape fabric at base of tree.
Weed control can be accomplished in several ways. One way is to use a combination of high quality landscape fabric (a 3’X3’ square for each tree, with the tree growing out a slit in the middle of the square) (Figure 7) together with a topping of 4 inches of coarse wood chip mulch over the fabric. This method is expensive and labor intensive up front, but if properly done and maintained, it needs to be applied only once. The most economical weed control is with herbicides, and the most economical herbicide is sulfometuron methyl (Oust XP). (See the appendix A for how to calculate Oust XP applications) Herbicides need to be reapplied every year for 5 years, or until the trees are well established.
Some people attempt weed control by mulching, alone. This seldom works, and requires so much material (at least 64 pickup loads per acre, to be effective) that it is impractical on any scale larger than a backyard. If done improperly, or with the wrong materials, mulch can cause some severe problems, including total failure.
Figure 8. Five foot tall tree shelter with fiberglass stake and bird netting.
Another important maintenance task is protecting young trees from animal damage. If there are any deer in the area, trees will need a 5’ tall, well ventilated tree shelter (Figure 8). Plantra, www.plantra.com, makes the best, and the most economical shelters. These shelters protect the trees from rabbits and deer, reduce mortality, increase rate of growth, decrease the number of years before nut-bearing begins, and almost totally eliminates the need from pruning (this is a huge job without tree shelters). Avoid unventilated or inadequately ventilated tree shelters. They will kill chestnut trees. Any time tree shelters are used, it is important to keep the vegetation mowed short between the trees, to keep mice from moving into the shelters and damaging the trees. Even if tree shelters are not used, mowing should be done to control the vegetation between tree rows–but mowing by itself is not enough to provide adequate weed control.
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 Aronia or highbush cranberry can be used as a barrier to block and absorb herbicide vapor drift.
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. Japanese beetles may become a serious problem, and will need to be treated with an 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 rabbits, mice, weeds, and insects.
Potential Disease and Pest Problems
The fungal disease called Chestnut blight can be a serious threat to chestnut trees. Most Chinese chestnuts are resistant or immune to the blight. A small percentage of Chinese seedlings will be susceptible. No other species of chestnut has as high a level of blight resistance. Phytophthora is another disease that can devastate chestnuts planted on poorly drained soil. There is no treatment. The only practical prevention is to plant Chinese chestnuts on well-drained soil.
Figure 9: Oak tree dying of oak wilt.Oak. Photo: Steven Katovich, USDA Forest Service, Bugwood.org
An emerging threat to commercial chestnut production in Iowa is the disease oak wilt caused by the fungus Bretziella fagacearum. The disease is virulent in chestnuts. Once infected, the trees are doomed. Symptoms usually start with yellowing and wilting of leaves, starting at the top of the tree and working its way down. The entire tree usually dies in a matter of days. By the time symptoms show in the 1st tree, the infection will already have spread, by root contact, to adjacent chestnut trees up to 100 feet away, dooming these also.
Figure 10: Lesser chestnut weevil, adult stage. Curculio sayi
The most practical way to stop the spread of the disease to other trees is to use a trenching machine to sever the root contact between infected trees and healthy trees. The recommendation is to trench 3 feet deep around any systomatic tree at a 100 foot radius. To reduce the chances of an initial infection, it is recommended to avoid planting chestnuts near forests with red oaks, avoid pruning between March and November, and sanitize pruning tools between trees.
The single most serious insect pest of chestnuts is the lesser chestnut weevil, Curculio sayi. The weevil bores through the chestnut bur just as the kernels start to form. Eggs are laid in the bore-holes made by the adult females. The hatching larvae burrow into the nuts. After feeding on the chestnut kernel and growing to about 1/4” long, the larvae chew a hole in the nutshell, exit the nut (see figure 11), drop to the ground, and burrow into the soil. This can happen while the nut is still on the tree branch or on the ground. The weevil larvae s
Figure 11: Larvae can emerge from the nuts while still on the tree.
pend about 18 months underground, where they pupate, and then emerge as adults in the spring. The adult weevils then wait nearby for the next chestnut crop, and the cycle is repeated.
Greg Miller of Empire Chestnut Co. of Carrollton, Ohio developed a heat treatment protocol to kill young chestnut larvae before they have a chance to grow and destroy the nut kernel. Nuts need to be gathered promptly after falling, then soaked in a hot water bath of 120°F for 20 minutes. Time and temperature need to be carefully controlled. Too long or too hot and the nuts are ruined. Not hot enough or not long enough and the larvae are not killed. If the larvae are allowed to grow too big, the heat treatment might not kill them. If followed carefully, this treatment will allow even infested nuts to be marketed, as the larvae are killed while still very tiny, and they “disappear” and are not detectable. Left untreated, the larvae grow into 1/4 inch long, white grubs which will ruin the nut and make it unmarketable.
Chestnut weevils can be prevented from even attacking the nuts by use of insecticide Treatments. The most effective is the group 3 insecticide bifenthrin (Sniper®). To prevent weevils from developing resistance, bifenthrin should be mixed with another insecticide from a different group, such as the group 1A insecticide carbaryl. Another approach to preventing resistance would be use of bifenthrin and carbaryl alone, in alternate years.
In the past, orchard sprayers or mist blowers were used to apply insecticide through the canopy of the trees. Recently growers are using drones for this application. Drones are more efficient in cost and application. Timing of application is critical. According to Bob Stelhi of Mantua, Ohio, growers should start collecting a sample of burs from the earliest-ripening tree, in mid August. The burs should be opened and the kernel checked for development. At the first sign of a kernel, the grower should spray. Usually a single application is sufficient, but if you see signs of larvae late in the season, a second application should be applied 20 days after the first (in subsequent years).
The chestnut gall wasp, which was introduced from Asia, causes severe damage to chestnut trees in some areas of the Southeast. The insect is slowly moving north and west, but might never reach Iowa. 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.
Once chestnuts begin bearing, the nuts will be very attractive to mice, chipmunks, squirrels, turkeys, raccoons, 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
Chestnuts are unlike apples, cherries, peaches, and m
Figure 12: Pruning a chestnut for clear trunk up to 8 feet.
ost other tree crops in that they do not need an annual pruning program. If grown without 5’ tree shelters, 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 12). This pruning is done during the initial establishment of the p
Figure 13: Location of pruning cut
lanting, 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 March through October 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 (Figure13). Once the 8’ clear trunk is achieved, the chestnuts need no more pruning. The use of 5’ tree shelters eliminates almost all the need for pruning.
Mowing
Mowing between tree rows will continue to be important even as the trees mature. The most critical mowing is done in mid to late August, and again just before nut harvest. Trying to harvest chestnuts hidden in tall grass is impractical if not impossible.
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 from municipal sewage or city yard waste. It often contains toxic substances. 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 or die later, then don’t use that compost on your trees. Organic fertilizers from commercial sources should be safe. The higher cost can be easily offset by the high value of the crop. 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. Elemental sulfur is probably the best choice of fertilizers for acidifying soil. Avoid aluminum sulfate. For soils with a pH above 8, it may be impractical to try to amend the soil, and you should probably just grow something besides chestnuts.
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 3-4 years). You can expect marketable quantities (100 pounds per acre or more) within 6 to 8 years, and a mature level of production (2000 pounds per acre or more) between 12 and 15 years (depending on site, management, and the varieties being grown).
Figure 14: Opening chestnut bur.
Starting in mid-September, the spiny burs which enclose the chestnuts (and protect them from squirrels) will begin to open up (Figure 14). Most of the nuts from any one tree will fall to the ground over a period of 3 – 5 days. That 3 – 5 day period will be different for every tree, and for a population of trees, may stretch from early September to late October. A few nuts get stuck in the burs and drop with the burs a few days or so after the main nut harvest for that tree. When the nuts are falling, You are racing against the squirrels, and 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. Mechanized alternatives range from very expensive, motorized, self-propelled machines, all the way down to a wire basket mounted on the end of a stick. We have tried several mechanical harvesters, and watched a few others work. The one we think works the best is “Holt’s Nut Wizard” www.holtsnutwizard.net (Figure 15). Don’t be fooled by cheap, Chinese made
Figure 15: Nut wizard harvesting chestnuts.
knock-offs. Those do not hold up under usage, and their “lifetime guarantee” is as useless as their machine is after one hour of use!
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 stored in mesh bags or double-bagged in craft paper. Plastic bags can work in a pinch, but the nuts will need to be cooled before bagging, and some holes will need to be punched in the bags to let the nuts “breathe.” 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. 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. Even with high demand, chestnuts are not a crop you can just take down to your local elevator – they have to be marketed, somehow. Several options are available. Chestnuts can be sold at farmer’s markets, grocery stores, health food stores, to wholesalers, or through the Internet, by mail order. Each of these outlets has its own set of advantages and challenges. The easiest is to sell directly to the Prairie Grove Chestnut Growers, located in Columbus Junction, Iowa, and run by Roger Smith (563-260-6333). There is no fee or application process – you only have to bring in quality nuts. Prices paid to growers ranged from $3.20 per pound for small nuts, up to $4.00 per pound for the larger nuts. Probably the most lucrative way to sell is through PYO (“pick-your-own” or “U-pick). The customers come and pick up the nuts every day. This eliminates costs for harvesting, sanitation, sorting, bagging, refrigeration, advertising, marketing, packaging, and shipping. All of those cost savings add up to pure profit, even if the nuts are sold at a slightly lower price.
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 Red Fern Farm. In 2025 Tom was offering a consultation service. Your first 15 minutes of any conversation, on phone or in person is free. After 15 minutes, Tom charges $100/hour for his time.
Red Fern Farm phone: 319-729-5905
13882 I Ave email: tom@redfernfarm.com
Wapello, IA 52653 Information is also available at www.RedFernFarm.com .
Appendix A: Oust XP Calculation Instructions
“Shortcut” for calibrating a Small (Backpack or Tow-Behind-a-Mower) Sprayer for Applying Sulfometuron Methyl (Oust XP) Herbicide in a Tree Planting
Note: These instructions are assuming a 3’ diameter circle will be treated around the base of each tree. If a continuous band along a tree row or a circle of a size other than 3’ is to be treated, a different calibration procedure will be required.
Before you put any Oust XP herbicide in your spray tank, you will need a digita
l scale capable of accurately measuring the granular Oust XP herbicide to within one tenth of a gram. A Cen-Tech Digital Pocket Scale model # 93543 is good for this, and is available from Amazon for about $30 or from Harbor Freight for about $15.
You need to get good at spraying 3’ diameter circles, and spraying them in three and a half seconds. On an area of pavement where it will be easy to see where the spray is applied, draw a series of 3’ diameter circles with chalk. Fill your sprayer with water and practice the motions and nozzle height needed to evenly apply spray to the inside of each circle. As you begin to spray each circle, start counting, “One thousand one…one thousand two…one thousand three…. Practice so that as you say the word “three” you have about ¾ of the circle covered, but continue spraying until the entire circle has been sprayed. Once you get good at spraying a 3’ circle in three and a half seconds, you will be applying spray at a rate of two square feet per second, or 0.165 acres per hour.
Now that you have your spray coverage rate figured out in acres per hour, you need to measure your sprayer nozzle volume output. Again, with your sprayer filled with water, set up a series of quart jars. Spray into the jars for 60 seconds (use a digital watch, or a watch with a second hand). See how many jars you fill in one minute. This number is your nozzle output in quarts per minute. [You can use the Calibration Calculator Excel sheet from this point on] Multiply this number by 15 to get gallons per hour. Now, divide gallons per hour by 0.165 (acres per hour) to get gallons per acre.
Oust XP is used in tree plantings at a rate of one ounce per acre. Your calculated gallons per acre is the number of gallons of water you need for an ounce of Oust XP. Obviously, this is way too much for your backpack or tow-behind sprayer. To find the right amount of Oust XP for your sprayer, first convert ounces to grams. There are about 28 and a half grams in one ounce. Divide 28.5 by your gallons per acre. This gives you the number of grams of Oust XP per gallon of water. Multiply this number by the number of gallons your sprayer will hold, and that gives you grams of Oust XP per spray tank.
Example: Say your nozzle output was 2 ½ quarts per minute. 2.5 X 15 = 37.5 gallons per hour.
37.5 gallons per hour divided by 0.165 acres per hour = 227 gallons per acre.
28.5 grams divided by 227 gallons = 0.13 grams per gallon of water
For a four gallon backpack sprayer, 4 X 0.13 = about 0.5, or one half gram per tankful
For a 15 gallon tow-behind sprayer, 15 X 0.13 = 1.95 or about 2 grams per tankful
Note: These numbers are ONLY applicable with a nozzle output of 2 ½ quarts per minute.
Oust XP herbicide should never be used on a tree in the year that tree sprouted from seed.
For math-lovers (the rest of you can ignore this), here are the calculations that show why 0.165 is the acres per hour for 3’ diameter circles sprayed in three and a half seconds:
According to the formula for the area of a circle A = pi r squared, 1.5 X 1.5 X 3.14 = about 7
7 square feet divided by 3.5 seconds = 2 square feet per second
2 square feet per second X 60 = 120 square feet per minute
120 square feet per minute X 60 = 7200 square feet per hour
1 acre = 43,560 square feet
7200 divided by 43,560 = about 0.165
Appendix B: Maintenance of trees in Shelters
Shelters are a great tool, but must be used properly. The instructions below are for Plantra 5 foot shelters and stakes.
Bent growth: Sometimes the growing tip of a young tree can get caught in the ventilation screen or on the edge of a punch-out hole, and get pointed downward. This can happen at the time the tree shelter is applied, or later, as the tree grows. It is important to look down inside each tree shelter at least once a week or so, to be sure the growing tip is pointing upward. If you see a growing tip caught and pointing downward, you can use a long, light-weight metal rod or a stiff piece of wire with a hook on one end, to reach in and down, to hook the growing tip and pull it upward.
Wasps: Paper wasps often build nests inside of tree shelters. When a seedling gets within 3” or 4” of the nest inside a shelter, the wasps somehow prevent the tree from getting any taller. Raccoons will also tear tree shelters apart to get at wasp nests in order to eat the wasp larvae. Wasp nests should not be tolerated. The easiest solution is to clap your hands hard, with the wasp nest still inside the tree shelter, centered between your hands. This crushes the nest, the larvae, and the adult wasps instantly. Tom has done this hundreds of times, and never been chased or stung. If you have a deadly allergy to bee stings, leave this job to someone else.
Japanese beetles: Japanese beetles can be absolutely deadly to young trees inside a shelter. Once the tree grows out the top of the shelter and stops growing leaves inside, you don’t need to worry. Japanese beetles can be excluded from shelters by using a barrier made of a fine plastic mesh. The bird exclusion netting provided by Plantra is now fine enough to keep out insects. Cut a slit in the netting to secure it to a tab (see below). You should do this just before the beetles start to show up. The mesh will eventually deteriorate in the sun, but it will last long enough for the Japanese beetle season. An alternative to the beetle barrier is a repellent. Neem oil works well for this, but it must be applied before the beetles show up, and re-applied every two weeks or so, for the duration of the beetle season. Probably the fastest, easiest, and cheapest solution to the beetle problem is the use of an insecticide with the active ingredient carbaryl. A one-half-second squirt from a sprayer wand aimed down the top of the shelter is all it takes. For smaller trees, Tom inserts the wand tip into one of the side punch-out holes to get the wand tip closer to the tree. A treatment of carbaryl will last up the three weeks, but should be re-applied in the case of heavy rain.
Stakes: We used Plantra fiberglass stakes on our farm. The next cheapest alternative is 1/2 inch rebar cut into 6 foot lengths. Both of these stakes can be woven in and out of the punch out holes in the shelter. The holes are designed for using zip ties or twist ties to go through and tie to stakes. We slide our shelters down, in and out of these holes, from top to bottom. This secures the shelter well, is very quick and leaves the nice twist ties, that come free with each shelter, for other purposes
Birds: Some cavity-nesting birds will fly down inside tree shelters, get trapped, and die. In Iowa it is usually bluebirds though phoebes and eastern wood peewees have been found dead inside shelters. Plantra tree shelters come with nets to place over the tops of the shelters to exclude birds. Pull the netting to just below the top punch out holes. Then pull one of the tabs from the punch out holes through the netting. When the top of a tree reaches the top of its shelter, the net needs to be removed.
Mice: Mice can be a serious problem in tree shelters. If you build up a high mouse population in a tree planting, shelters become a bed and breakfast spot for mice. The best way to prevent this is to keep your mouse population in check. If you keep the vegetation mowed short in between the trees, it leaves the mice open to predation from hawks, owls, foxes, coyotes, and house cats. The mouse population will remain low enough that it does not become an issue for tree survival. As an added precaution, you can drop a moth ball down inside each tree shelter. Mice do not like mothballs.
Rapid growth: The rapid tree growth generated by shelters needs to be balanced. You should never let a tree get too tall without producing side branches. When the tree is at least 2’, but less than 3’ out the top of the shelter, pinch off the growing tip at the top of the tree. This will temporarily stop the upward growth and encourage the tree to start putting on side branches. You may have to go back and pinch off new growing tips once a week, until the desired side branches start growing.
Removal: Shelters can be removed when the trunk diameter is more than 1 ½ inches at the top of the shelter. For some people, an easy gauge is to try to wrap your thumb and index finger around the trunk where it exits the shelter. If you thumb and finger can touch, leave on the shelter. If you cannot touch, you can remove the shelter. This varies with hand size.
Buck protection: We place a 20 inch long length of 6 inch black corrugated drain pipe, with a slit cut up the side, on our young trees before removing tree shelters. When you remove the shelter, the pipe stays to protect the young trees from rubbing by buck deer antlers. The pipe should be 10 inches above the ground and continue upward 20 inches. Weeds may hold it in place or you may need to tie string from the top of the pipe to a low branch. When the tree fills up the pipe, remove the pipe. It is not needed anymore.
Summary: While all of this might seem like a lot of maintenance, with just a little practice you can trim the time needed to monitor each shelter to just a few seconds per week. The added advantage in tree survival and growth will be well worth the effort.
Appendix C:
Sources of Nursery Stock
Canopy www.canopynursery.com/ Champaign, IL
Olivia’s Orchards near Parnell, Iowa and run by Elana Gingerich. This small nursery offers chestnut, pawpaw and other fruit trees. Her website is at www.oliviasorchard.org/
Lola’s Nursery www.lolasnursery.com Drew Westburg of Muscatine, Iowa. Small nursery with chestnut trees. 319-350-2105
Valley Chestnuts www.valleychestnuts.com Sperry, Iowa
Hillbilly Tree Farm Sperry, Iowa 319-985-2468 Small nursery
Plate Specialty Seedlings Grinnell, Iowa and managed by Andy Plate. 641-990-7350, email andy@plateseedlings.com or visit the website at https://www.plateseedlings.com/
Route 9 Coop, 4300 Germano Rd SE, Carrollton, OH 44615. www.route9cooperative.com Source of high quality Chinese chestnut seed nuts and nursery stock. Greg and Amy Miller.
England’s Orchard and Nursery, 316 S. R. 2004, McKee, KY 40447. 606-965-2228. www.nuttrees.net . Source of a wide selection of fruit trees and some nut trees.
Sources of Chestnut Seed
Red Fern Farm Tom Wahl & Kathy Dice. www.redfernfarm.com/index.php/product/seed-nuts/
13882 I Ave., Wapello, IA 52653. 1-319-729-5905. Great source of seed.
The Center for Agroforestry University of Missouri https://centerforagroforestry.org/resource/chestnut-resource-hub/ These seeds will come from grafted trees, pollinated by other grafted trees. They are expensive, but with great genetics. Be sure to research which varieties will be best for your area. The seeds are may be infested with chestnut weevils.
Route 9 Coop (see info above)
Sources of Equipment/Supplies
A. M. Leonard, 241 Fox Dr. Piqua, OH 45356-0816. 800-543-8955. www.amleo.com . Source of horticultural tools and equipment.
Central Landscaping, 4026 County Road 74 South, St. Cloud, MN 56301. 1-320-252-1601. www.centrallandscapesupplies.com . Wholesale only (you must be a business) supplier of lawn, garden, and landscape equipment. Low cost source of deer repellents.
Forestry Suppliers Inc., PO Box 8397, Jackson, MS 39201 1-800-647-5368 . www.forestry-suppliers.com . Retail supplier of a wide variety of tree-related equipment and supplies, including deer repellents, landscape fabrics, and tree shelters.
Books
Tree Crops by J. Russell Smith. Out of print, but in the public domain.. Also available all across Iowa through interlibrary loan. https://archive.org/details/TreeCrops-J.RussellSmith
Permaculture: A Designer’s Manual by Bill Mollison. Available from Good Earth Publications, (704) 863-2288, or through inter-library loan.
Nut Tree Culture in North America, Edited by Richard Jaynes, published by the Northern Nut Growers’ Association. Out of print, but available through inter-library loan.
Nut Growing Ontario Style by John H. Gordon Jr. Available through inter-library loan.
Organizations
Appropriate Technology Transfer for Rural Areas (ATTRA). www.attra.org . Lots of good, free information. Ask for materials list at 1-800-346-9140.
Iowa Nut Growers Association (INGA). www.iowanutgrowers.com Good source of information on growing a wide variety of nut trees.
Nebraska Nut Growers Association. Www.nenga.wildapricot.org Good source of information, seed nuts, and scionwood for grafting (but not much on chestnuts).
Northern Nut Growers Association (NNGA). nutgrowing.org Advancing the cultivation of temperate zone tree nuts since 1910. Excellent source of information.
North America Fruit Explorers NAFEX
Prairie Grove Chestnut Growers. (563) 260-6333. Brokerage run by Roger Smith. Buys and sells chestnuts. Located in Columbus Junction, Iowa www.prairiegrovechestnutgrowers.com
USDA National Agroforestry Center. www.nac.unl.edu . They publish a number of technical bulletins on incorporating trees into agriculture.
Savanna Institute www.savannainstitute.org Nonprofit that supports agroforestry in the Midwest.