Post on 09-Aug-2015
Season Extension & Cold Frames
Compiled by EAC Staff, August 2014
Season extension & cold frames
Workshop facilitator notes
Sample workshop [1-1.5 hours] Compiled by Jen at the Ecology Action Centre “Flow of information”
Group introductions [5 min]
Season extension [5 min]
-Why do it?
-How to do it?
-The growing season, before and after
-Spring [5 min]
-Fall [10 min]
Examples and additional tips [5 min]
Engage:
Option 1: building a recycled window cold frame
[1 hour]
Option 2: planting in a pre-built cold frame [30
min]
Season Extension
Season extension means extending the traditional gardening
season- that is, extending the time a crop is normally able to
grow outdoors, or giving plants a head start before the season.
This is done by creating certain conditions for your plants that
allow them to grow before warm weather, and past the onset
of a colder season. Extending the season can include the use of
cold frames, row covers, and even grow-lights. In summary,
season extension is a way of gardening that allows you to make
the most out of the growing year.
What is the “growing season”?
The growing season length, according to “Climate Change NS” includes “The number of days between the dates when the mean daily temperature exceeds 5ºC.” Currently this includes approximately 200 days, and is expected to increase in number as climate change affects the region. The growing season tends to start somewhere around mid-April and ends in October. However, frost warnings are often in place up until the end of June, and again October 1. This is when frost-protection strategies come into play, as you will discover later on in this document.
Home Harvest, the “edible landscaping company,” based in
Halifax, designed a Planting Guide based on Nova Scotia’s
growing season. See Appendix A.
Before the season
Spring: “starting early”
A practice gardeners will use as a head start to the growing
season is starting seeds indoors before frost warnings lift. Many
people start seeds beginning in March, or
as early as February. Seed-starting indoors
requires a system of container trays,
potting mix, sufficient space, regular
watering, and lots of light. The light
source can either be natural or artificial.
Some people start seeds in a window that
gets a lot of sun. Larger-scale seed starting
may involve a heated or unheated
greenhouse.
Artificial lighting usually means using a grow-light. Grow-lights
are designed specifically for seed-starting and sometimes even
full plant growth. Using grow-light methods can be as simple as
using a fluorescent light bulb, or as elaborate as grow-light
plant stands (pictured). Lights can be purchased from Halifax
Seed, Lee Valley, hydroponics stores, or online.
Seeds need to be planted according to their needs (check the
package or online), and watered regularly to avoid drying out,
especially when they’re just sprouting. If you’re using a grow
light system, you’ll need to set a timer to give the plants
approximately 12 hours of light. Once seeds are established as
plants (usually with a few sets of leaves) and the growing
season has started, they can be transplanted outdoors into the
garden.
After the season
Fall: “growing beyond”
The keys to ensuring successful season extension include heat-
retention and frost-protection. From The Winter Harvest
Handbook by (Eliot Coleman), the three basic components to
winter harvest include: cold-hardy vegetables, succession
planting, and protected cultivation.
1) Learn the cold-hardy vegetables: the
ones that tolerate colder weathers and
have lower light requirements. This
includes spinach, swiss chard, carrots,
mache, lettuce, leeks minutina, arugula,
beet greens, raab, pak choi, kale,
parsley… to name a few! These
vegetables like cooler weather. Planting
some in Spring and again in August for a
Fall harvest is a great way to make the most of time in the
growing season. See the Appendix C for a full list of cold-hardy
vegetables.
2) Succession Planting: this is the process of planting things
continuously so that you can enjoy a constant bounty and a
nonstop, staggered harvest. Tips on planting vegetables at
intervals throughout the seasons include: a) Choosing season-
appropriate cultivars, b) the pick and sow method: picking and
then “seeding” every few weeks (starting new seeds), and c)
familiarizing yourself with the planting calendar.
3) Protected cultivation: this just
means plants under cover. In season
extension this includes row covers,
smaller hoop houses, greenhouse-size
tunnel hoop houses (pictured), or cold
frames, which act as a miniature
greenhouse.
Other tips & examples for extending
season:
raised beds: raised beds are more accessible, manageable,
and they heat up sooner in the springtime! They reduce
weeds and allow for better drainage and the development
of nutrient-rich soil, resulting in higher yields. It’s also easy
to attach a hoop house to a raised bed, or turn a raised
bed into a cold frame!
mulching: mulching regulates the temperature in beds,
supporting the plants during the season, and acting as a
“blanket” for plants over the winter. Mulching is a great
habit to get into- using hay or straw, woods chips, or dried
leaves works.
using a “cloche” or hot cap: this is any
material used as a protective covering to
shield plants. Ex. a plastic jug, an old
punch bowl, or a jar. Cloches may be
used early on in the season when there is
still risk of frost or cooler nights- for
example, protecting a newly-
transplanted tomato.
alternatives to cold frames: straw-
bale cold frame to protect winter
leeks/other tall vegetables ie. kale
and collards.
interplanting: similar to companion
planting, this is planting things to get the
most out of space by combining plants
which have different maturity dates, growth
patterns, and space needs in order to
maximize space.
Building a Cold Frame: Plan and Process
Recycled Window Cold Frame Construction
Introduction
The following guide will enable you to prepare a cold frame using rough cut lumber and a recycled window. The construction is intended to be simple, make use of easily accessible material, and be safe. Note: Lumber cuts are based on rough cut wood
Wood Required and Cuts:
(3) 12’ – 2x6: These will be cut to specifications within the Instructions section under
Window Measurements and Wood Cuts.
(1) 6’ – 2x2: (2) cut at 17” and (2) cut at 11”
Other Materials:
4” Hinges (2) recycled or new
Recycled exterior window with wooden frame
(10) #8 – 2” wood screws
(50) #10 – 3” wood screws
Tools Required:
Impact drill or screwdriver with square (#2) bit
Drill with 1/8” bit
Measuring tape
Carpenters square
Pencil
Circular saw or handsaw
Construction Plan:
1) Window Measurements and Wood Cuts
2) Back Frame Construction (1) & Front Frame Construction (1)
3) Frame Sides (2) Installation 4) Window and Hinge Installation
Instructions: 1. Window Measurements and Wood Cuts Measure the length and width of the window and record these measurements. With a circular or hand saw, cut five pieces of 2x6 at the same measurement as the width of the window. For the frame sides, cut six pieces of 2x6 four inches shorter than the length of the window, this will accommodate for the added width of the window frames during installation. For two of the frame side pieces, make a straight cut using a circular saw, hand saw or jig saw from one corner to the opposite corner in a diagonal fashion, thus creating a triangle (sloped piece) at the same length as the other frame side pieces. 2. Back Frame Construction (1) & Front Frame Construction (1)
For the back frame, lay three of the pieces cut to the window’s width on a flat surface; the
edges of each should be flush with each other and their longer edges abutted to one another.
With a measuring tape and carpenters
square or straight edge, draw a line
2” in from each end of these boards
so that the line is perpendicular to
the longer edges of each.
Lay two of the 17” pieces on these
boards aligned with each of the
previously drawn lines. Ensure that the
2x2s are flush on the edge of the 2x6 that
will be the bottom of the cold frame.
Prior to fastening these to the boards,
predrill two holes for each board within
the 2x2 to ensure the pieces do not split
when being fastened.
Fasten each 2x2 to the boards, keeping the outside edges of the 2x6s
flush; do this with the #10 – 3” wood screws. The front frame will be
completed in the same fashion but with the 11” 2x2 pieces as the connecting pieces.
When stood upright and facing each other from the inside the back and front frames should
look like this:
3. Frame Sides (2) Installation
Two 2x6 pieces will be stacked and fastened to the 2x2 pieces of both
the front and back frames. This can be done with the #10 – 3” wood
screws. With two stacked on each side, the third (sloped) 2x6 pieces
can be appended to the top of each frame side. The cut for the
sloped piece should extend from one corner of the 2x6 piece to the
opposite corner so as to create a triangle. A good way to make this
cut safely using a circular saw is to fasten one side of it to a wooden
surface, leaving the cut line clear of the surface so the saw will not
cut down into it. With the
piece fastened with at least
two screws at different
places, slowly cut the
diagonal.
Before fastening these sloped pieces of 2x6, predrill
two holes about 4” apart near the thinner end of
each piece so that the wood does not split during
drilling.
Front
Frame
Back
Frame
Fasten each to the 2x6s below with the #10 – 3” wood screws and then fasten the back end
of the sloped 2x6 to the back frame 2x2s to secure the piece in place.
Now that the overall frame is complete, the window can be fastened to the frame using
the hinges; ensure the frame looks like this before proceeding:
4. Window & Hinge Installation
Lay the window so that its edges align with the edges of
the cold frame.
At 5” from each edge of the upper 2x6 (back frame),
draw a line on both the 2x6 and window frame; this will
serve as a guide when installing the hinges.
Fasten each of the hinges to both
the back frame and the window
frame using #8 2” wood screws;
the hinges should have their outer
edges in line with the lines
previously drawn.
Now that the build is complete, it is good practice
to open and close the lid to see if there are any
issues with the hinges and to ensure the fit is snug.
In addition, we recommend that absorbent
material such as soft piping tubing or something
similar be appended to the edge of the sloped 2x6
so that contact between the window and cold
frame does not break the glass.
Back
Frame
Add Absorbent
Material Here
Placing the cold frame
Placement of the cold frame is important, in order to maximize
growing potential. The idea is to find a “micro-climate” on your
site. In this case, it’s the spot that is south-facing, and perhaps
warmest. Niki’s tip “a good indicator is: where the snow melts
first in your yard”
Activities for a group
Hand out planting calendars. Appendix A and B are examples of
growing calendars. Draw a theoretical garden. Have
participants pick out vegetables they’d like to see grown, and
then have them learn their growing times by referring to the
calendars. This will help to identify the cold-hardy vegetables,
which are ideal for the extended season (Fall and Winter
months). Then, make a “cold frame plan” with selected
vegetables.
If you have a cold frame available, plant it with either seeds or
transplants.
Resources
Halifax Garden Network: http://halifaxgardennetwork.com
Year-Round Vegetable Gardener- Niki Jabbour
The Winter Harvest Handbook – Eliot Coleman
Appendix A
Home Harvest Planting Guide
Appendix B
The Growing Calendar
Appendix C
Cool-tolerant vegetable charts