Prairie Nursery | White Paper Site Preparation and Prairie Seeding Methods I) Site Preparation Site preparation is a critical step that, if overlooked, can lead to disaster in short order. This is especially true of areas with a history of weedy growth. All the existing vegetation and weeds must be killed prior to seeding. It takes only a few rhizomes of quackgrass, Neil Diboll, Consulting Ecologist bromegrass, Canada thistle, or Canada goldenrod to quickly re- With over 40 years of experience colonize the planted area. The mantra for soil preparation when in research and establishment of native plant communities, Neil is an preparing a site for a prairie planting is simple: TAKE NO PRISONERS! internationally recognized pioneer in the use of North American plants in There are many different methods of preparing a site for seeding to contemporary landscapes. His designs a prairie meadow: emphasize sustainability, aesthetics, and ecological compatibility with the 1) Smothering with black or clear plastic for a full growing season land. Neil is a regular keynote speaker 2) Smothering with a single layer of cardboard or multiple layers on topics such as establishing prairie of newspaper, covered with leaves or grass clippings for a full meadows, designing with native plants, and the benefits of converting growing season resource-intensive landscapes into self- 3) Planting a summer buckwheat smother crop, followed by fall sustaining ecological sanctuaries. planting of winter wheat, usually for two successive seasons www.PrairieNursery.com PRAIRIE NURSERY P.O. Box 306, Westfield, WI 53964 1 800-476-9453 PRAIRIE NURSERY blue: #62cbe9 green: #68934d Portada Text : Book Site Preparation and Prairie Seeding Methods 4) Repeated deep soil tillage every three weeks for a full growing season 5) Sod removal on lawns with no weeds, using a sod-cutter 6) Bulldozing all vegetation and their roots and rhizomes from the site 7) Herbicide treatment using Roundup or similar glyphosate herbicide, with added broadleaf herbicides to kill Roundup-resistant weeds, if necessary If perennial weeds are well established one to two years may be required to completely kill them. This can be accomplished using year-long smothering, repeated applications of herbicides, or regular, repeated tillage with equipment that uproots and kill perennial weeds. After the perennials have been eliminated in the first year. weed seeds that are harbored in the soil can be allowed to germinate and killed by application of herbicides in the second year.. Tilling weed seedlings to kill them is generally ineffective, since every time the soil is disturbed new weed seeds are brought to the surface where they can germinate. If a weedy “old-field” is selected for planting to prairie flowers and grasses, one full year of site preparation is a minimum. Sometimes one and a half to two years of site preparation may be required to get weeds under control before planting. This allows for the elimination of the perennial vegetation in the first growing season, and control of the weed seeds in the soil in the second year by spraying every 6-8 weeks, without tilling or disturbing the soil. Smothering with Black Plastic or Cardboard Smothering is a cheap and effective method for killing herbaceous vegetation. Rolls or sheets of black or clear plastic can be staked into the ground to deprive weedy vegetation of moisture, and in the case of black plastic, light. A full growing season of smothering is required to kill perennial weeds, and some pernicious species such as Canada Thistle (Cirsium arvense), Field Bindweed (Convolvulus arvensis), and Crown Vetch (Coronilla varia) will often require two or even three years of smothering to deplete their extensive root reserves and kill the plants. There are a number of drawbacks to using plastic as a smothering material. First, it is produced from petroleum products. Secondly, it is difficult to recycle. Thirdly, it is subject to puncturing, especially by deer hooves, digging animals, and pets. Other options for smothering materials include old carpets, cardboard, and newspapers. Carpets are good for smothering small areas. Newspapers are subject to blowing, and can only be applied on a calm day and must be covered immediately with mulch such as lawn clippings, leaves, or logs to hold them in place. An excellent smothering material is cardboard. It is often available for free, covers large areas, is less subject to blowing than newspapers, and decomposes to add organic matter to the soil (as do newspapers). Large appliance shipping boxes are often available at local stores for the asking. They make the job of smothering quick and easy. Cover the cardboard with lawn clippings or leaves to hold them in place for the full growing season. If you are going to seed the area that has been smothered, the plastic, newspapers, or cardboard will usually have to be pulled up to expose the soil. However, if the organic material that was applied over newspapers or cardboard has decomposed to humus, and www.PrairieNursery.com PRAIRIE NURSERY P.O. Box 306, Westfield, WI 53964 2 800-476-9453 PRAIRIE NURSERY blue: #62cbe9 green: #68934d Portada Text : Book Site Preparation and Prairie Seeding Methods the smothering material below it has disintegrated, seed can be applied directly into the upper organic humus material. This provides an excellent seed germination environment. If installing transplants, simply move the organic material away to expose the old newspapers or cardboard. It should be damp and easy to cut through. Make an incision into the mulch material to expose the soil and dig a hole for the plant. After installing the plant, return the mulching material around it to hold in moisture and prevent weed seed germination. This is one of the easiest and environmentally friendly methods of installing a prairie garden (or any garden for that matter). Please note that smothering does nothing to control the weed seeds in the soil, as they remain basically unaffected. If possible, it is best to plant seeds directly into the decomposed leaves or other organic material that was applied over the cardboard or newspaper when seeding a prairie. Inorganic materials such as plastic, carpet, etc. must be removed prior to installing either plants or seeds. Smother Crops Smother Crops are annual plants that deprive other plants and weeds of sunlight to kill them. Smother crops have the benefits of requiring no herbicides, and they add organic matter to the soil. Two successive years of smother crops are required to control weeds in abandoned fields that have grown up to a variety of perennial weeds and grasses. The most commonly used smother crop is buckwheat (Fagopyrum esculentum). It is often used in conjunction with winter wheat (Triticum aestivum). Buckwheat grows rapidly and produces many layers of large leaves along its stems that deprive plants below of sunlight. It was commonly used in agriculture as a rotational crop for controlling weeds prior to the advent of herbicides. The area to be planted to buckwheat should be plowed under in mid to late spring after the weedy vegetation has begun to grow. This will set back the weeds, and provide a competitive advantage to the buckwheat. Smooth the field in preparation for seeding. Plant the buckwheat at a rate of 50 pounds per acre in June, after all danger of frost has passed (buckwheat is intolerant of freezing temperatures). Allow the buckwheat to grow until it begins to flower, usually in mid to late August, about two months after seeding. Cut it down when in full flower, before seeds begin to form. If seeds are allowed to form and drop to the ground, buckwheat will return in the next two to three years, and can compete with future prairie seedings. After cutting down the buckwheat in August, it should be immediately plowed under to add organic matter to the soil. Allow it to sit for two to three weeks to decompose, as the green stems can give off ammonia that may affect your next crop seeding. In mid September, smooth the soil and plant a crop of winter wheat to help hold the soil over winter and to reduce weed competition from any remaining weeds. When the winter wheat comes up the following spring, allow it to grow and produce early seedheads, usually in late May to early June. Cut it down, plow it under, and allow it to sit for a week or two to decompose. Then plant a second crop of buckwheat before July 1 to www.PrairieNursery.com PRAIRIE NURSERY P.O. Box 306, Westfield, WI 53964 3 800-476-9453 PRAIRIE NURSERY blue: #62cbe9 green: #68934d Portada Text : Book Site Preparation and Prairie Seeding Methods control any remaining weeds. When the buckwheat is in full flower, cut it down and plow it under, as in the previous year. The area should now be ready to seed to prairie that autumn. If seeding in late fall, the site should be lightly disked before seeding to kill any weeds that have germinated from seeds in the soil seed bank. If seeding in spring, plant a second crop of winter wheat in the second fall. Cut it down the next spring, plow it under, and prepare the field for seeding your prairie. Soil Tilage Soil Tillage is an option for killing weeds on level sites that are not subject to erosion. The ground can worked using a chisel plow, cultivator, a rototiller, or similar implement that reaches down at least six inches into the soil to disturb the roots of undesirable plants. With repeated tillage, their root reserves are eventually depleted and the plants die. The strategy is to allow the plants to re-grow three to six inches tall after each tillage event.