What can you tell me about fertigation techniques for blackberry production?
Answer: Dr. Bernadine Strik and Dr. Luis Valenzuela of Oregon State University, Dr. David Bryla of USDA-ARS produced a webinar titled Organic Blackberry Production: Tips Learned from an Ongoing Research Study, which you should find useful. It covers the impacts of weeds on blackberry growth and yield; methods for weed control; fertigation for planting establishment; the effects of post-harvest irrigation on productivity, plant water status, and soil moisture; and root growth in blackberry.There has not been a lot of research on organic fertigation schedules that are best for the crop. Each organic farm has had to do some experimenting. There are some guidelines to follow though once you determine the total amount of fertilizer you need for the season:1) Don’t apply it all at once. 2) Add 30 to 40 percent of the total amount of fertilizer needed in the beginning of the season and the rest throughout the growing season, so that the plants get nutrients as they grow, and so that you don’t lose nitrogen before the plant can use it.3) Try to time the applications so that most of the nutrients have been applied by the time fruiting begins.4) For each fertigation session, start irrigating and make sure water has pressurized all the drip tape before starting the fertilizer injector.5) Always flush the drip lines for about a half hour after stopping the fertilizer injection.For more information or organic fertigation and injectors, consult the primer Fertigation in Organic Vegetable Production, produced by eXtension.org. It includes a list of organic fertilizers for fertigation and prices per unit of nitrogen so you can compare apples to apples.