March 2020 - 7

PRODUCTION
CONTINUED FROM PAGE 1
vegetable production, cover crops and
research fields, and four 30-foot by 96foot
hoop houses.
Both drip and overhead irrigation are
used. " Blights and many other diseases
don't establish without free water on the
leaf surface and that's why we use drip
irrigation, " Moghtader said. Drip also
allows fertigation when supplemental
nutrition is needed in-season.
Overhead irrigation is used
occasionally to fully moisten the soil
profile and stimulate soil microbial
activity. " The biological activity that
drives nutrient availability in an
organic system requires moisture, "
Moghtader said.
Varied irrigation needs
The irrigation strategies vary with
the crop.
For some crops, like kale and spinach,
overhead irrigation is used to get the
soil moisture up to the right level before
planting to aid establishment. Drip
irrigation is used later in the season for
routine watering. Drip irrigation keeps
the environment drier than overhead
irrigation and reduces disease.
For tomatoes, some early overhead
irrigation is used before transplanting
but drip is the primary irrigation.
Overhead irrigation is used for early
cucumber establishment followed by
drip irrigation.
Bed width and length, and the
number of rows per bed, are carefully
planned to fully utilize space, suppress
weeds and make harvest as efficient as
possible.
Shorter crops like baby greens are
typically grown on a system of 30-inch
beds with a 12-inch path for workers
and eight beds per hoop house. The
number of rows per 30-inch bed varies
with the crop.
Managing water, weeds and spacing are crucial elements in efficient hoop house production.
Lettuce is planted in three rows per
30-inch bed with an eight-inch, in-row
spacing that aligns with the drip emitter
spacing. Kale is planted two rows per
bed with a 12-inch, in-row spacing.
Spinach is planted in five rows per bed
and baby greens in 16 rows per bed -
both at tighter in-row spacings.
The ultimate goal is to maximize
the linear feet of the beds and the
linear feet of the rows on the beds. The
system can be intercropped with beds
of smaller, short-season crops and beds
of taller, full-season crops to maximize
production. This is important where the
number of hoop houses are limited or
entire houses of a crop can be planted
all at once or in succession depending
on marketing needs.
Tomatoes and cucumbers are
typically grown on six-inch wide beds
with a 36-inch path for workers. This
puts the rows about 42 inches apart
which puts eight rows per 30-foot hoop
house. Tomatoes are spaced 16 inches in
the row and cucumbers 12 inches in the
row. Both of these crops are vertically
pruned and trellised to overhead wires.
Peppers, a more medium-sized crop,
is planted in three-inch beds with a 24inch
path which puts rows 27 inches
apart. The peppers are spaced 12 inches
in the row and basket woven.
Fabric hits the mark
The beds are marked out and then
built with a bed roller. The Campus
Farm uses landscape fabric that covers
both the path and all but a narrow
planting opening of three to five inches
wide rather than plastic on the beds.
" Landscape fabric is more reusable
and fits better, " Moghtader said.
" We really like the ability to apply
overhead irrigation at times, so we
like the permeability of landscape
fabric. " This permeability allows for
the full wetting of the soil to stimulate
microbial activity.
" We like the air flow through the
fabric, " Moghtader said. " It also gives us
solid walking paths that are weed-free. "
The landscape fabric also doesn't have
the cooling effect on early season soil
temperatures that mulches like straw
have. These cooling effects can slow
plant growth in warm season crops like
tomatoes and peppers.
The three- to five-inch open bed
top between the pieces of landscape
fabric also allows for sidedressing
with dry organic fertilizer like bagged,
composted poultry manure which the
farm uses for higher biomass, longer
term crops like trellised tomatoes.
The Campus Farm uses copious
amounts municipal compost at start up.
" Municipal compost has lots of leaves so
it has less nitrogen than other composts
but does have lots of organic matter, "
Moghtader said. The organic matter
really helps with water retention, soil
structure, and nutrient holding capacity
along with driving microbial activity.
" We put six inches down - or about
50 yards - along with any other needed
amendments before the hoop house
ever goes up, " Moghtader said. " This
initial investment is worth it in the
high-value production space. We want
to be set for a long time. " VGN
VGN | MARCH 2020 | 5

March 2020

Table of Contents for the Digital Edition of March 2020