Brambles - Production Management and Marketing

Bulletin 782-99

Chapter 2 Site Selection

Eight basic factors must be considered in selecting a site for a bramble planting. These are soil type and natural fertility, water drainage, air drainage, wind protection, sunlight, water availability, isolation from wild brambles, and previous crops in the field.

Select soils for brambles that are well-drained, high in humus or organic matter (2 to 4% retentive of soil moisture, and somewhat naturally fertile. The soil should be slightly acid (pH 5.8 to 6.8). Brambles prefer sandy loams or loams to coarse sands or clays. Sandy loams retain enough moisture in the summer while allowing water to get away from the roots in the spring and fall. Trailing type blackberries tolerate heavier clay soils better than other brambles. A soil that contains 50 to 100 pounds available phosphorus per acre, 220 to 300 pounds potassium per acre, 150 to 200 pounds of magnesium per acre, and a cation exchange capacity (CEC) of 8 to 16 is ideal.

Water drainage is a critical issue in site selection, because the root systems of bramble fruits extend to a depth of three feet. Avoid subsoils that are tight and impervious. The water table should not come within three feet of the soil surface, because bramble roots are sensitive to low oxygen supplies. When the water table rises and fills the pores in the soil, oxygen is forced away from the roots. Further, the roots become susceptible to root-infecting fungi. Roots die, causing a stunted, shallow-rooted plant that is stressed by summer heat and lack of moisture.

To determine if a site needs water drainage, dig a number of test holes in the area to be planted. The holes should be the size of post holes and one to three feet deep. If the subsoils are brown to reddish brown, they should be loose enough for good root penetration. If they are yellow or gray, they are probably tight and impervious. Dig test holes in early spring or late fall when the soil is saturated with water and is not frozen. Pour five gallons of water into the hole and check it after one hour. If there is water standing in the bottom of the hole, drain tile may be required at that site, or even if drain tile is installed, the soil may be too wet for brambles. Gravel subsoils, on the other hand, may allow water to leach away too quickly. Consult your local Soil Conservation Service for additional information. A small trial planting of brambles using tile and raised beds may be necessary before a large investment is made.

Make the planting on slightly sloping soils. This will improve surface water drainage and help in air drainage (which will be discussed shortly). If slopes are steep and cultivated, erosion will be a problem. Equipment cannot be driven safely on steep slopes. These types of locations should not be planted.

Air drainage is as important to bramble plantings as water drainage. Adequate air movement around the plants is essential. Air movement reduces humidity around the plants in the summer, drys excessive moisture, and prevents conditions that promote and spread disease. Air movement also reduces the danger from spring frost. When plantings are on higher, sloping sites, cold air will flow down the slope to the lowest possible spot in the area. Because cold air settles, late spring frosts are less likely to damage the planting if the cold air can drain away.

Figure 4. Air movement reduces moisture and humidity around the plants in summer, prevents conditions that promote and spread disease, and provides protection against late spring frosts.

Protect plants from strong winds. Raspberry plants are especially susceptible to cane whipping and breakage from the wind. Strong winds blowing across a planting evaporates soil moisture and desiccates young plants. When soils are frozen, plants cannot replenish lost moisture and may be killed. High winds may blow off a snow cover, increasing evaporation. Wind can also pile snow too deeply on the plants, causing cane breakage from the weight.

Irrigation of the crop will be discussed later in this bulletin, but a source of adequate water for irrigation must be considered in site selection. The site must be near a well or a farm pond to get water to the plants economically.

Exposure of the planting, although not critical, should be considered. Brambles respond to somewhat cool, protected areas; thus a northern slope is preferred. A southern slope can be used, but the temperature of the plants may be high during the day in the winter. With a few warm days in February, buds may be stimulated, and a "cold snap" could damage the crop.

Make new plantings as far away from wild brambles or from older plantings as possible. Destroy wild brambles for a minimum of 1,000 feet from the planting and, if possible, one-quarter mile away. This is to prevent the spread of disease into the new planting.

Brambles should not be planted in an area where strawberries, tomatoes, potatoes, eggplants, peppers, or other bramble crops have been planted. These crops are susceptible to Verticillium wilt, and the fungus can survive in the soil for many years.