Chapter 3: Site Preparation
The previous chapter (Chapter 2: Site Selection) reviewed the most important factors that should be considered prior to seeding a new ginseng garden. Briefly, these include the selection of a well-drained loam soil, on a fairly level site. The prospective planting site should be carefully walked and any areas of questionable drainage have been flagged. The soils on the site have been reviewed by reading the description contained within a Natural Resources Conservation Service Soil Survey map. (link to NRCS web site)

Start with best site
Some of the best sites for cultivated ginseng in the Northwest are ones that have been in either small grain or alfalfa cultivation. These fields don't have trees or brush to clear, nor do they have a plethora of perennial weeds such as quackgrass, bindweed, Canada thistle, among others. After the grain or forage has been cut, one application of a broad-spectrum herbicide such as Roundup (glyphosate; see Figure 1), followed by perhaps 2 passes with a disc, is often all it takes to prepare a field for bed shaping and fall seeding. Deep plowing generally not recommended. It can lead to the formation of clods that are hard to break down for bed shaping.

Consider leasing farm ground
On the westside of the Cascades, where farming parcels are smaller, growers often approach landowners that have traditionally grown forage crops, and ask if the land can be rented for 4-5 years for the production of ginseng. With farm ground lease rates as low as $150/acre/year, renters can start a farming venture much more economically than if they had to purchase the land. Thus far, there does not seem to be a theft problem of mature roots, as most people don't know what is grown under the black shade structures! As long as the renter can gain access to the garden with tractors and other machinery, a ginseng garden lease can prove to be mutually beneficial to all parties involved. After the crop has been harvested, all the posts wire, anchors, and shade cloth can be gathered and used for another planting.

Contracting garden preparation
New growers should seriously consider contracting out the preparation of their beds. An experienced farmer can spray the pasture, disc it, and seed a soil-enhancing cover crop. Plan to spend at least $30/acre for contract tillage and other prep activities. New landowners with limited farming experience can learn alot from looking over the shoulder of a veteran farmer!

Pasture ground
Landowners with pasture ground that has traditionally been used for livestock are often disappointed with the costs associated with their upkeep and the meager returns they may achieve. Landowners with horses find that they are not enjoying their animals as much as they once might have. It is not uncommon for rural landowners to ask University extension advisors for suggestions as to farm enterprises that can be lucrative. Well cared for pastures can become ginseng gardens quite easily, with the herbicide and tillage strategy outlined above. These fields often have minimal weed pressure and possess good organic matter levels. Pasture ground that has had minimal upkeep however, can be a challenge. Often there is brush and small trees that first need to be cleared. An un-kept pasture with tansy ragwort, thistle, and blackberries will require considerably more effort to bring into production.

Dealing with brush
All too often landowners consider the use chain saws, brush hogs, or even heavy machinery to clear the grass, shrubs, brush, and trees on their property. Using such implements often does not completely dig up the woody root systems of trees or deeply rooted perennials. An over-all herbicide application of Roundup helps considerably, but there can still be too much re-growth. For woody brush and small trees there are some very effective forestry techniques, such as girdling, overall herbicide application with a brush killing herbicide, and cut stump herbicide applications that can be used to completely kill the woody vegetation before the dead brush is cleared or ground out. Ideally all of this work is done at least a year prior to planting ginseng. It takes at least one year to drag out the remaining roots that are often left after the brush has been removed. If this material is left in the soil it can harbor pathogens, insects, and nematodes which can all have a very detrimental effect on the future ginseng crop.

Brush burning
One final note on land clearing. Landowners who clear brush from the land often choose to burn the woody debris. Many counties in areas west of the Cascades have initiated burning ordinances that inhibit burning as a way to improve air quality. If burning is allowed don't construct burn piles where the ginseng is proposed. The wood ashes release very high levels of potassium, which can harm the ginseng. In addition, the soil pH will be raised to levels much too high for ginseng growth.

Soil drainage considerations
During the last 8 years that ginseng has been re-introduced into the Northwest, root rot problems associated with poorly draining soils have become an all too often occurrence. As discussed in the Site Selection section, growers need to fully understand the physical makeup of the site in question. Soil survey maps (Natural Resources Conservation Service) can provide a detailed description including one of the most important considerations: soil permeability. This term describes the relative ease at which moisture will pass through a soil layer. A good ginseng soil consisting of a fine sandy loarn texture is considered to have a moderate permeability. A coarse gravely sand would have a very rapid moisture movement. Heavier soils, such as clay loams, and true clays would have slow to very slow permeability rates. If the Soil Survey description states that the land has a slow draining texture, it may be entirely too difficult to alter it for ginseng cultivation.

In areas west of the Cascades there are a number of indicators of poor drainage. Ponding of water on the soil surface after a heavy rainfall can occur if the soil structure is very fine. Some fields simply lie in areas of a high water table, that all too often is not evident during the dry summer months. Don't buy or lease land for ginseng cultivation until it has been carefully walked during the wet season. Just because a pasture looks good in the dry summer months, it may not have the drainage capacity during the winter.

Previous cropping
The previous cropping strategy the land received can impact the drainage qualities of a soil. Over grazed pastures, which have received years of compaction, tend to have very slow permeabilities. Row crops such as corn and other vegetables, which receive clean cultivation in combination with herbicides, often have lower organic matter levels. On these sites soil particles will disperse, thus leading to puddling of the soil surface. Farm implements themselves can lead to slower water infiltration rates. Years of shallow discing can result in the formation of a compaction zone or "tillage pan" through which water will pass slowly.

If the proposed ginseng garden site has well drained soil, but has a plow sole layer which restricts water permeability, the site can be subsoiled. This practice, simply defined, is the practice of loosening the soil beneath the surface. In the Northwest either a "Para-til"subsoiler (3' dog-leg ripper shank) or a v-ripper (parabolic curved shank with V configuration) can be pulled behind a heavy duty tractor during the dry months of the summer to loosen the soil at a depth of 3 feet.

Dealing with water tables
For fields with high water tables, subsoiling will have to be combined with sub-surface drainage tile installation. Recently the trenchless plow has become the standard implement for drain tile installation. In this case a large single shank is pulled through the soil at 3-4' depth. At he base of the shank a chute delivers a continuous line of tubing down the back of the shank. Tubing (see Figure 2) consists of 4" diameter perforated high density polyethylene (HPDE) tubing. Drain tile depth can range from 3' to 5', with 4' often used as the design depth. Drain tile depth can be reduced to 2.5' if the soil it is laid into is slowly permeable, or where a hardpan, rocky, or other dense layer exists. A number of different designs can be used to lay out the tile system in a field. In a parallell system, excess soil moisture flows laterally downhill in tile lines placed perpendicular to the slope of the land. Laterals tie into a collector mainline which empties into an outlet next to a ditch or stream. In a herringbone configuration, laterals are can help drain a swale in the field. In either system, the spacing between laterals should be based on soil type, drain depth, and the desired trafficability.

Narrower spacings result in better control of the water table, but also increase the costs associated with more tile and the labor to install it. Lateral spacings of 30' are common on poorly drained soils west of the Cascades. Each field is different. There are drain tile contractors in the Northwest that can not only design a tile system, but can also do the installation. Plan to spend $800-$1,000 per acre on drain tile and installation on fields that require it. If the same piece of ground will be farmed for a period of years the up-front cost of tubing will easily be re-couped as a result of the improved yield.

Raised planting beds
Despite the best efforts in improving the drainage properties of the native soil, ginseng growers can still see yield reductions due to the prolonged wet weather inherent to the Pacific Northwest. The combination of 80% shade, a layer of mulch, and often heavy soils, especially west of the Cascades can reduce root yield. Seeding ginseng on 8-10" raised beds has become a standard planting practice. With a slight crown on raised beds water will be diverted into the alleyway between the beds and allowed to run out at the base of the garden. Care should be taken not to allow workers to step onto raised beds. The lack of traffic on raised beds over the 4 year cycle will ensure that they don't become compacted and thus will continue to allow good drained into the alleyways.

Improving the soil
Wild ginseng prefers the rich humus soils of the Appalachians in the eastern portion of the eastern part of North America. These soils have as much as 10% organic matter, as a result of thousands of years of deciduous leaf fall and decomposition. In order to simulate rich forest conditions, western growers revert to adding a number of different amendments prior to planting their gardens. In Ontario, ginseng farmers have been known to add 20-40 tons/ac of cow manure a year prior to seeding a ginseng garden. The manure needs to be complety broken down before the garden is planted in order not to impart off flavors to the roots!

Soils rich in organic matter are typically loose and friable encouraging vigorous ginseng root growth. Organic matter can either be added to the site as an amendment, or can be developed by using incorporated cover crops. Besides manure as described above, organic matter could include woodwastes including shavings, sawdust; and composted crop residues, including tree clippings, or leaves.

Cover crops suitable for the Northwest include

Cereals such barley, oats or wheat, planted in the spring, at 100 lbs. per acre	Faba beans planted in the fall 1 year prior to planting again at 100 lbs. per acre
Cereals such as winter rye planted 1 year prior to planting, also at 100 lbs. per acre	Winter legumes, including winter peas and hairy vetch planted in the fall at 50 lbs/acre

In areas west of the Cascades cereal ryegrass is often planted in mid-September so that it has time to grow before fall rains slow growth. Farmers like the amount of biomass it makes over the winter. It is often necessary however, to cut the ryegrass the following spring before discing however, as the ryegrass will have put on so much growth.

If site preparation is not started until the spring of the planting year, May seeding of cereals after April spraying and discing, can be successful. After the cereals are harvested and the stubble disced under, bed shaping can be conducted. Cover crops sown on a site prior to ginseng will enrich the soil when they are turned under as they increase organic matter levels, and improve soil tilth.. Their thick growth habit during the summer helps choke out the growth of annual and perennial weeds.

Soil pH
Ginseng naturally prefers a slightly acidic soil pH, as is normally in the forests of Appalachia. The optimum pH has been found to be on the order of 5.6 to 5.8. Prior to planting a ginseng garden, soil pH should be tested by using an analytical lab, preferably one that can make recommendations for ginseng cultivation. At a pH of less than 5.5 or greater than 6.5 root growth slows. Optimum soil pH ensures that the ginseng roots absorb essential plant nutrients. On the west side of the Cascades, soils are generally acidic due to the abundant rainfall that dislodges the calcium and magnesium ions from the soil colloids. Unless lime is applied periodically, soils simply become acidic over time. Ground limestone or dolomite is typically broadcast spread and incorporated into the planting site. Applications should be made prior to planting, as surface applications of the calcium ion tend to move into the soil too slowly.

East of the Cascades, soil pH can be as high as 8.0, especially in areas of limited rainfall. Elemental sulfur can be spread and incorporated prior to planting. It is generally harder to lower soil pH than it is to raise pH. Sawdust mulch, applied after the beds have been seeded, will lower the soil pH somewhat. Using fertilizers such as ammonium sulfate, will also help.

Fumigation
Ginseng roots can be damaged by high levels of either Columbia root knot nematodes (Meloidogyne hapla) or root lesion nematodes (Pratylenchus penetrans). Chapter 13: Insect Management provides a visual and written description of these pests. As with other horticultural crops, growers are advised to sample future planting sites to determine both the identity and number of nematodes in a given sample of soil.