Blackberry plants prefer temperate conditions. A member of the Rosaceae family, the blackberry plant can have long, arching canes or be more erect like shrubs. Many varieties bear thorns while certain hybridized varieties are thornless. No matter what type of blackberry plant you are growing, the soil requirements are all the same.
Soil pH Factor
Soil is typically acidic or alkaline and this is designated by a pH rating. Fortunately, blackberry plants are capable of growing in a wide range of soil pH ratings though they seem to do best when the rating is between 5.2 and 6.5. To check you pH value, submit a soil sample to your local extension office. The results will show your pH value and te extension office will recommend what can be added to the soil to modify the rating. Ideally this should be done about 1 year before planting.
Types of Soil
As with the pH value, blackberry plants can tolerate many different soil types. This is why they are found growing wild in so many locations. In order to promote the best fruit production, however, blackberries like a sandy loam type soil. Another plus is soil that has a high content of organic matter because it helps keep soil from becoming compacted. Roots are able to spread out more easily to seek water and nutrients in this soil environment.
Of all the small frit crops, blackberries are among the later ones harvested. Because they grow longer than other small fruits, they are still growing during the height of summer’s heat and require more water than other fruits. Deep watering should be done often to prevent soil conditions from drying out. Adding mulch will help retain moisture. With all this watering it is important not to let standing water build up around blackberry plants as this will drown the roots.
The soil test you had done to determine the pH of your soil can also inform you of any soil nutrient deficiencies. Berry crops including blackberries, typically need supplies of potassium, magnesium, calcium and boron. These are absorbed by the roots. It’s a good idea to add this to the soil and work it in well before planting so the nutrients are available to the roots. It is more difficult to get them down to the roots of established plants.
Get the Soil Ready
If you are getting your soil ready at least a year before planting thee are things you need to do besides amend the Ph and add nutrients. Prevent weeds from taking hold in the planting site. Once in, they will rob your soil of the nutrients you have just added. They are also harder to eradicate once they are established. One idea for managing this is to plant a cover crop like rye, oats or buckwheat. Cut it down and plow it under, adding organic matter to the soil, before it goes to seed. goes to seed, it should be plowed under. This adds organic matter to the soil which helps keep soil from becoming compacted and helps increase nitrogen levels.
Related Articles: Growth of Wild Blackberry Plants
Sources: University of Maine: Growing Raspberries and Blackberries
Cornell University: Site and Soil Requirements for Small Fruit Crops