Blackberry V-Trellis Construction
This short step-by-step guide is to help new growers build a V-trellis
for growing blackberries. The supplies needed and the steps to build the
trellis are included. This guide was developed by a tlaented group from NC Cooperative Extension (Nancy Power and Paige Burns), Sandhills Research Station (Jermy Martin) and the Sandhills AgInnovatoin Center (David Goodwin). Their contact information is at the end of this blog post.
 |
| Figure 1. Blackberry V-trellis with 30" board to keep T-posts separate. |
Supplies:
|
Item(s)
|
unit cost ($)
|
cost per 100’ row (rounded to nearest $)
|
|
two 8’
round, wooden end posts, 4” diameter
|
10
|
10
|
|
eight 6’
steel T-posts*
|
5
|
40
|
|
400+
feet 12-gauge galvanized wire
|
$105/1000
ft
|
11
|
|
two 2 x
4 boards, 23-30” long
|
$10/10
ft
|
4
|
|
16 T-post
pin-lock insulators
|
$10/bag
of 25
|
7
|
|
2
gripples
|
$31/pack
of 20
|
3
|
|
floral
tape
|
2
|
2
|
|
4 galvanized
barbed staples or poultry staples
|
$4/bag
of 52
|
0
|
|
total cost per 100’ row
|
|
$72
|
Tools:
-
100’
or longer measuring tape
-
spinning
jenny
-
gripple
tightening tool
-
pliers
-
post
pounder
-
tapener
-
watering
can or water bottle or hose
-
shovel
-
hammer
or mallet
*If row is
100’ or less, T-posts can be up to 35’ apart in the row; if row is >100’,
25’ apart is the recommended maximum.
Procedures:
Wear
safety glasses, especially for hammering the posts and working with the wire.
1.
End
post (Figure 2).
a.
At
each end of the row, insert an end post into ground about 6’ from the end berry
plant by one of the following methods:
i. Pound post in with a pile driver
ii. Dig or auger hole 3’ deep
b.
Insert
post and have one person hold it upright
c.
Add
a little soil to the hole
d.
Pound
soil in hole with the handle end of a shovel
e.
Add
a little water
f.
Repeat
the above three steps until the hole is full and packed in tightly (about four
rounds).
 |
| Figure 2. Metal T-post brace hammered into wooden 8' end post. |
2.
Row
posts (Figure 3).
a.
Using
measuring tape, lay T-posts out at 25-35’ intervals, starting at 2’ beyond the
end plants (4’ in from end posts). If
the row is 100’ or shorter, the spacing can be up to 35’. If the row is longer than 100’, a 25’ spacing
between posts is recommended.
b.
Set
up a brace post (Figure 2):
i. Insert a T-post in the ground about
16” in from the end post, with the base of the T facing the end post, angled so
that it the T-post extends past the end post.
ii. Pound the T-post into the ground at
an angle until the top is next to the end post.
iii. Push the top of the T-post so that
it is inside the end post.
iv. Use the side of the post pounder or
a mallet to pound the T edge into the wood.
v. Repeat for the other end post brace.
c.
Use
the post pounder to insert the other T-posts 25-35 feet apart, in pairs, at a
20-30° angle so that each
pair makes a “V.” (See Figure 16a in Southeast Regional Caneberry
Production Guide)
d.
Use
pliers to attach 2 insulators on the outside of each T-post, one at the 5th
notch down on the post, and one at the 16th notch (roughly at 4’ and
a man’s knee height), with the pin at the top.
Put the pin in the hole of each insulator.
e.
Turn
the L-shaped rods inward on the spinning jenny and add a roll of 12-gauge fence
wire. Turn the L-rods back outward over
the wire.
f.
Pull
on one end of the wire to wrap the wire around the outside of the end posts and
T-posts at knee level, threading the wire through the insulators as you go.
g.
Where
the ends of wire meet, thread each end through the gripple, allowing for
“tails” on both ends of the wire.
h.
Use
the gripple tool to ratchet the wire fairly tightly, but not as tightly as possible.
After the posts set (in a few weeks), the wires can be tightened
further.
i.
Insert
a 2x4 horizontally between the T-post pair at each end of the row. Push the board down till it fits tightly
between the T-posts (Figure 1). You may
want to size and cut the board after the rest of the trellis is assembled, to
make sure it fits.
j.
At
the outside end of each end post, hammer a staple in far enough to hold the
wire in place vertically but to allow the wire to move horizontally for
tightening.
 |
| Figure 3. Pow posts: 6' metal T-posts with 12-guage wire running through black plastic insulators facing outward. |
If desired,
the lower wires can support ¼” irrigation hose.
This construction guide was repared
by:
Jeremy Martin, Research Operations Manager,
Sandhills Research Station, 910-974-4673.
Nancy Power, Commercial Horticulture Agent, NC
Cooperative Extension, Richmond County Center, 910-997-8255.
Davon Goodwin, Manager, Sandhills AgInnovation
Center, 910-992-8176.
Paige Burns, County Extension Director, NC
Cooperative Extension, Richmond County Center, 910-997-8255.
Reference:
Fernandez, G.E., E. Garcia, D. Lockwood. 2016.
Southeast Caneberry Production Guide. AG-697. https://content.ces.ncsu.edu/show_ep3_pdf/1604932460/22996/
