RCA trellis with covers

RCA trellis with rowcover, Piedmont Research Station, Salisbury, NC. Photo: K. Snider. 

Blackberry canes with emerged buds, under rowcovers. Photo: K. Snider. 

At the Piedmont Research Station in Salisbury, NC, we have a set of four RCA trellises oriented  North/South and East/West. The primary objective of this project is to evaluate attributes of fresh blackberry fruit. We are most interested in the level of sun scald based injury to fruit based on canopy orientation.

However, the RCA trellis is used in colder regions of the country as a way to grow varieties that are not cold hardy. In North Carolina, twice in the past decade, we have experienced low temperatures (8 April 2007 and 12 April 2012)  that have resulted in significant crop loss. Developing flower buds and therefore the blackberry crop were killed by late season frost/freeze events. So, we are looking at this trellis system as an option for protection from cold in NC.

Temperatures at the Piedmont Research Station in Salisbury, NC, for the have been cold, 20F on 21 March. We had emerged buds so we protected blackberry plants under rowcovers. Although the buds would likely have survived, we wanted to protect them, just in case. We have data loggers recording temperatures under the covers and will download them next time we get to the field and update this post to include those temperatures.

Are you ready for spring?

Andy Rollins,  Clemson Extension Service sent me this image last week. In the circle are some basal buds breaking at the base of pruned cane as well as some buds further up the cane. Daylength, temperature (cumulative and current temperature) and plant hormones are key components that determine when buds on a plant will break.  The daylengths are getting longer, 12 hours and 7 minutes in Clemson SC last week when this was taken.  Chilling hours (cumulative temperatures between 34-45F) is at 325 units, according to one model, however, I think the real chilling is higher (the inception time depends on a temperature trigger of 28F and that first occurred this winter in January). The chilling unit accumulation at the Piedmont Research Station, in Salisbury NC, where some of our research plots are planted is over 1300 units. Daytime temperatures are getting warmer, although they are not staying warm, so continued growth will not occur for a while.

However, spring is not far away. Get pruning done, trellises repaired, irrigation system prepped, winter pesticide applications out (lime sulphur on blackberries has to go out at delayed dormant before buds are 3/4" long). See SRSFC IPM guide for the latest recommendations. http://www.smallfruits.org/SmallFruitsRegGuide/Guides/2012/2012BrambleSprayGuide.pdf

WInter Caneberry Checklist

Blackberry and Raspberry Seasonal Checklist
Winter 2012-13
Gina Fernandez, Small Fruit Specialist
North Carolina State University

This checklist was originally developed for blackberry growers in North Carolina. Many of the items apply to raspberry production as well. You may have to adjust your work activities either earlier or later depending on your location. For more detailed information, check the Southern Region Integrated Bramble Management Guide and the Southeast Regional Bramble Production Guide at: http://www.smallfruits.org/SmallFruitsRegGuide/index.htm.

Check the items off as they get done. This list is very general, but should help get you to think about what types of activities occur at various times of the year. If you would like other items to be added to this list, send them to me and I will add them next time.

WINTER
Plant growth and development
√ Plant is not visibly growing during the winter months although many blackberries will retain their leaves through the winter
√ Some differentiation is occurring in the flower buds
√ Low chilling cultivars can break bud in January after adequate winter chilling. You can monitor chilling hours accumulated in eight states in the eastern US by accessing this site: http://www.nc-climate.ncsu.edu/cronos/blackberry/index.php

Pruning and trellising
√ Pruning should occur in late winter.  However, in some areas winter ice storms can do tremendous damage to plants and trellis systems. If you produce blackberries in one of these areas, pruning can take place early winter to help avoid severe damage.
√ Make trellis repairs after plants have defoliated but before pruning and training.
Erect types
√ Prune out the spent floricanes
√ Tie canes to wires in a fan shape
√ Cut lateral branches back to 8-12”
√ Thin canes to 6-8 canes/ hill (4 ft spacing)
Trailing types
√ prune out spent floricanes
√ tie or weave canes to wire so that they do not overlap
√ prune side laterals to 12-18”
√ thin canes to 6-8 hill (6-8ft spacing)
Primocane fruiting raspberries and blackberries
√ Prune (mow) primocane fruiting types to ground level

Weed control
√ Many summer weed problems can be best managed in the fall and winter using preemergent herbicides. Determine what weeds have been or could be a problem in your area. Check with local extension agent for cultural or chemical means to control these weeds.

Insect and disease scouting
Check the Southern Regional Bramble integrated Management Guide for recommendations. www.smallfruits.org

√ To learn more about the spotted wing drosoplila and how it may impact your fruit in 2013, check out Hannah Burrack blog, she has lots of links in addition to her blog posts
√ Scout fields for insect and disease damage and remove those canes
√ Remove wild blackberries and raspberries by the roots if they are within 600 ft of your planting during the winter or treat with glyphosphate in the autumn
√ Apply liquid lime sulphur or Bordeaux for disease control before new buds are 1/8”

Planting
√ Take soil tests to determine fertility needs for spring plantings.
√ There are some new raspberry and blackberry cultivars available in 2013. If you have not tried them or it is not know how they will do in your region, it is best to order a small quantity to see how well they will perform in your area
√ For larger growers, prepare list of cultivars for 2014 plantings and order now. Smaller quantities of plants can be order in early 2013 for spring 2013 planting
√ A commercial small fruit nursery list at http://www.fruit.cornell.edu/berry/nurseries/

Water management
√ Make repairs to irrigation system (check pumps, lines, etc)
√ Plants generally do not need supplemental water in winter

Marketing and miscellaneous
√ Order containers for next season
√ Make contacts for selling fruit next season
√ Attend grower meetings:
o The 2013 North American Raspberry & Blackberry Conference Meeting
√ January 27-30, 2013 in Portland OR. http://www.raspberryblackberry.com/local.cfm?doc=webdocs%2FNorthAmericanBerryConference2013.htm
o 2013 SE Regional Fruit and Vegetable Conference
√ Jan 10-13, Savannah GA
http://www.seregionalconference.com/
o The North Carolina Commercial Blackberry and Raspberry Growers Association
√ Feb 19, 2013.  Shelby NC. For more information contact Daniel_Shires@ncsu.edu or Josh Beam <josh.beam@dole.com>

NOTE: NC Cooperative Extension will be taking over the Blackberry and Raspberry Information Portal in early 2013. The site will have essentially the same material, but a new look. Links will be provided from the old site to the new site.

***This information (originally written by me) also appears in the latest SRSFC newsletter******

Chillin' in NC?

Today it was 56 F in Raleigh, NC. I am loving the warm temperatures, but I am getting worried about lack of chilling. As of 4 pm today, we have accumulated 119 chilling hours, last year on the same date, we had 399 hours. We usually get about 1000 or more hours in the area.

High chilling/low chilling. Most of the blackberries and raspberries we grow in NC need to accumulate a high number of chilling hours in order to break bud and grow 'normally' next summer. Contrary to what you may initially think, we don't want low chilling plants. We want high chilling plants that can stay dormant when we get January thaws. However, this year it does not look like we are making progress to that high chilling number. We will be keeping track of it over the next few weeks. 

If you live in the SEUS, you can find probably find out the chilling hours in your area.  The NC State Climate office has a great tool you can use if you want to calculate the chilling hours in your area. Here is a link. http://www.nc-climate.ncsu.edu/cronos/blackberry/