A Weed-Free Planting Site

• According to the Ontario-based Esson Estates Winery Coop, more blackberry crops are lost to weeds than any other pest or disease. If you plan to grow organic berries, begin your weed suppression at least two to three years ahead of planting. This can mean incorporating a lot of well-rotted manure or aged compost and repeatedly cultivating the soil or covering the planting site with black plastic, which essentially heats the soil to a temperature inhospitable to weeds. If you choose to apply an herbicide, use broad-spectrum, post-emergent herbicide the summer before planting. Control weeds by shallowly cultivating around the plants; they have shallow weeds, so cultivate no deeper than two inches.
  
  

Nutrients

• Blackberries love nutrient-rich soil. Incorporate as much compost or manure as you can at least three weeks before planting. Dig the soil deeply with a rototiller; loosen as much soil as you can. If you have less-than-ideal soil, thorny varieties will grow better than thornless ones. ‘Himalaya Giant’, for example, is the best variety to grow in poor soil conditions: the cultivar’s excess vigor is tempered by the poor soil but it will still produce a good crop.
  
  

Water Retention and Drainage

• Blackberries, like all berries, will not tolerate wet soil. They should not be planted on low, wet sites because they are more prone to frost damage and root rot. Incorporating a lot of organic matter will help the soil drain well while also retaining moisture. The more organic matter you can incorporate prior to planting, the less you will have to irrigate throughout the season.
  
  

Virus Disease Reduction

• Blackberries are susceptible to lots of diseases, the most severe of which, verticilium, is shared by several other types of berries and vegetables. The University of Maine Extension does not recommend planting blackberries where other berries have grown, or where tomatoes, peppers or eggplant have grown in the last 4 years. The university also recommends destroying other raspberry and blackberry plants within 600 feet of your planting site.
  
  

Herbicide Persistence

• The first year of a blackberry plant’s existence is crucial to its establishment. It is during this first year that the plant establishes a strong root system. Herbicides that persist in the soil from the previous year can adversely affect the success of the plant’s establishment, impeding the development of its root system and leaving it more prone to disease.