Growing European cucumbers can be an easy addition to your tomato crop. The same customers usually purchase tomatoes and
cucumbers. Therefore, adding cucumbers to
your line of products may help you diversify, while not requiring that you establish a new
list of customers
Benefits
Cucumbers are considered a quick crop because it only takes about 2 weeks to get a
seedling ready for transplant. Once the
cucumber plant is transplanted to its final spacing, production should begin in about 30
days. Fruit harvest can continue for 90 days
or more.
Cucumber plants require 8 - 10 square feet of greenhouse space compared to
tomato spacing of 4 - 5 square feet of greenhouse space per plant. This means that only half as many cucumber plants
are required to properly fill the same area.
Cucumber plants like higher nitrogen levels and can be grown in USED media
that has been previously used for growing media for other crops.
The plants like warm, humid conditions. Being
a member of the melon family, they grow very well in the weather conditions that are
characteristic of the southern part of the U.S.
The plants are heavy producers - yields of 30+ lbs per plant from a 4 month
crop are possible during the longer days of late Spring and Summer.
The plants are all female and the flowers do not require pollination.
Selecting
seeds
European cucumber seeds are available for full sized fruit that is usually
harvested when the fruit weighs about one pound. “Mini”
varieties are harvested when the fruit is about the size of a large dill pickle. These varieties of cucumber seed are specifically
produced for greenhouse production. These
varieties are capable of producing fruit without pollination. The seeds grown within the fruit are sterile, and
immature. They will not produce another
generation of plants.
Many of the newer varieties of seeds have been bred with resistance and/or
tolerance to various diseases that have been a problem to growers in the past.
The time of year you choose to grow the crop may determine the size of fruit
that you desire. During the long days of
Summer, all fruit tends to reach its maximum length.
During the short days of Winter, the fruit tends to mature at a shorter length. Some growers will select a shorter variety during
the Summer months and a longer variety during the Winter months. Their customers receive fruit that is very similar
in length throughout the year. Some markets
request different sizes of fruit and you may need to make your seed selection based upon
the fruit length requirements of your market.
Planting
the seed
Seeds are usually started in 2" or 3 1/2" Net pots and are ready for
transplant in 10 days to 2 weeks. When
planting the seed, it is best to lay the seed flat.
The taproot will extend out from one end of the seed and the growing point of the
plant will come from the other end. If you
plant the seed with one end pointed down, there is a good possibility that you will have
planted about half of your seeds upside down. Lightly
cover the seed with about 1/4" of media. Planting
the seeds too deep can delay germination and increase the possibility of losses caused by
“damping off” fungus.
Once you have finished planting the seeds, thoroughly wet the media with
plain, room temperature water. Cover the seed
flats with a single sheet of newspaper. Mist
the newspaper with plain water until the paper is completely wet. The newspaper will become a “blanket”
over the seed flats. It will help to
stabilize the temperature around the seeds. It
will allow a slight amount of air circulation. As
the paper dries out, it will serve as an indicator of when to water the seed flats again. If you are starting your seedlings in a
greenhouse, the newspaper will also serve as a shade clothe to keep the temperature of the
growing media within the proper range. Temperatures
about 85o F. can
“cook” the seeds. When sunlight
shines on any dark growing media, it absorbs heat and the temperature of the media can
rise much higher than the air temperature. The
best germination temperature is 75can
“cook” the seeds. When sunlight
shines on any dark growing media, it absorbs heat and the temperature of the media can
rise much higher than the air temperature. The
best germination temperature is 75can
“cook” the seeds. When sunlight
shines on any dark growing media, it absorbs heat and the temperature of the media can
rise much higher than the air temperature. The
best germination temperature is 75
Although these seeds are expensive, you can expect nearly 100% germination in
2 - 4 days. Water with plain water until the
seeds have germinated. The newspaper should
be removed once the seeds have germinated. Once
the seedlings have emerged from the media, apply Mycostop and Guardian nematodes. Use 1/2
strength fertilizer solution adjusted to a pH of 6.5 - 6.8 for the remainder of the
seedling stage.
One final note as you start these seedlings.
I don’t think a year has gone by that I don’t get at least one call from
a grower who has lost a portion of their seeds to MICE.
If you are going to grow your seedlings on the floor - or if your benches are
positioned where mice can get on top of them - do something to
keep the mice away from your seeds.
Growing
Media
The growing media used for cucumbers is the same as tomatoes - it can consist
of a wide variety of medias, including: peatlite mixes; coarse, aged sawdust/pine bark;
soil; perlite; or rockwool. One cucumber
plant will require as much growing media as two tomato plants.
Transplanting
Cucumbers need 8 - 9 square ft. of greenhouse space per plant. This is double the spacing required for tomato
plants. As an example, if your greenhouse was
30' x 120' (or 3600 sq. ft) it would hold 400 - 450 cucumber plants. In this example, the plants would be set out in 5
rows of 80 - 90 plants per row.
Two support wires are positioned over each row, about 28" - 30"
apart. Assuming the rows are running North to
South, we will call the support wires over each row, the East wire and the West wire. Unlike tomato plants, cucumber plants are brittle
and will not be “leaned and lowered” when they reach the support wires. As the seedlings begin to grow, a plant clip is
used to attach a support string to each plant. Every
other plant will be attached to the East support wire, with the alternate plant being
attached to the West support wire
The support strings are attached to the support wires on a slight diagonal. As an example, all strings attached to the East
wire would be attached to the support wire 18" - 24" North of the vertical
position of each plant. All strings attached
to the West wire would be positioned 18"- 24" South of the vertical position of
the plants. This diagonal angle will help the
developing fruit hang away from the main stem of the plant.
The initial growing temperature for cucumbers is 68o F. nights and 80o - 85o
F. days. They will tolerate higher temperatures if the
relative humidity is 70% or more. The night
temperature can be lowered to 65o
F. when the plants reach
the support wire.
Initial
pruning & training
As the plants begin to grow, it is important to allow them to develop a strong
root system. A strong root system will enable
the plant to support more fruit and grow quicker. During
this phase of their growth, all laterals (suckers), fruit and tendrils should be removed. Continue this pruning until the plant has
developed 10 true leaves. The plant will be
about 3' high before you allow any fruit to develop.
This will take about 20 days from the time of transplanting. Keeping the fruit removed during this stage of
growth allows the plant to develop a strong root system.
The last few leaves in this stage of growth should develop to nearly
12" across.
As the plants grow, the support string should be twisted around the stem,
approximately one revolution every 6" - 9".
Always twist in the same direction. The
string should be carefully positioned to not damage any developing fruit. If you start twisting in a “clock-wise”
direction, continue twisting in a “clock-wise” direction all the way to the
support wire. You don’t want to change
the twisting direction to “counter clock-wise” half way up the plant. This could cause a serious problem when you begin
removing the lower leaves from the stem. With
proper twisting, you will probably not need to use any more plant clips until the plant
gets close to the support wire.
Once the cucumber seedlings have been transplanted, you can begin feeding them
a full strength, high nitrogen, fertilizer solution.
Maintain the night temperatures at 65o
- 68o F. at the flower level. The relative humidity should be kept at 70% - 85%. A misting system is beneficial for keeping the
relative humidity in this range and as an added benefit; a misting system will help to
keep spidermites under control. As the plants
begin to grow, you will notice that they require 25% - 50% more water than tomato plants. Generating additional carbon dioxide within the
building is also helpful during the daylight hours - when the exhaust fans are not running
Hang yellow sticky ribbons and begin a monitoring program for insect pests. The primary insect pests of cucumbers are
whiteflies, spidermites and thrips. These can
be controlled using biologicals if releases are made before the pests get out of control.
After
10 leaves
After 10 true leaves have developed on the plants, you can begin developing
fruit. If all conditions have been maintained
properly, this should be about 20 days after transplanting.
The plants will be about 3' high at this time.
If the plants are setting multiple flowers at a leaf node, you should prune down to
only one flower at each leaf. Behind each
flower will be a small embryo fruit. Select
the straightest embryo fruit to mature. If a
fruit is curled or crooked, it should be removed. These
curled fruit will never straighten out and should not be allowed to waste the energy of
the plant. If you allow multiple fruit to
develop on the main stem leaves, later developing flowers will probably abort and you may
find that you weekly production swings from peaks to valleys.
No pollination is required for these fruit to develop. The plant is all female and will produce fruit
that contains sterile seeds. These seeds will
not mature. It is believed that mature
cucumber seeds cause some people to “burp”.
Because of the immature seeds, these fruit are considered “burpless”.
As the plant continues to grow up the support string, remove the lateral
growth (suckers) and the tendrils. If the
tendrils are not removed, you will notice that they can grab hold of a developing fruit
and damage the appearance of the fruit. The
flowers should be thinned to only one straight fruit for each leaf. Continue twisting the growing point around the
support string. At this stage of growth, the
plants will be growing nearly 6" per day. The
fruit will mature to a harvesting size in about 10 days.
During this stage of growth, bottom leaves should only be removed if they are
interfering with your watering system or if they are beginning to discolor.
It is important that you maintain adequate water and fertilizer levels for the
plants as they begin to set fruit. You should
always watch the growing point of the plants and make sure that it remains strong. The stem of the plant should be about 1/2" in
diameter. The flowers should be a good color,
a good size, and it is good to have at least 2 flowers trying to develop at each leaf
node. However, if you are developing more
than 2 flowers per leaf node, you may be feeding them slightly more fertilizer than they
need.
If you have a conductivity meter, you should compare the conductivity of the
incoming solution to the plants with the solution that is leaching out of the bottom of
the growing media on a weekly basis. Approximately
10% - 20% of the solution going in the top of the media should be running out the bottom
each day. The conductivity of your
“leachate” solution should be 10% - 20% higher than what is going in the top.
If the conductivity of the
leach solution is:
a) Less than the conductivity going in
the top - you should increase your fertilizer level.
b) Equal to the conductivity going in
the top - you should reduce the amount you are watering.
c) 10% - 20% higher than what is going
in the top - your feed & water is OK.
d) Greater than 20% higher than what
is going in the top - you should increase the number of
waterings per day (and possibly
leach the media with plain water to reduce the fertilizer levels
in the media).
As
the plant approaches the support wire
As the growing point of the plant approaches the support wire, you should begin
removing bottom leaves - 2 or 3 leaves at a time - at a weekly rate that is equivalent to
the number of new leaves being set at the top of the plant.
At this point, you have reached a good balance of leaves for photosynthesis
and proper production. However, pruning is
necessary to maintain proper ventilation within the plant canopy for fungus and insect
control. Excessive pruning at any given time
can cause too much moisture loss in the plant and may result in aborted flowers. It is better to remove 2 or 3 leaves - wait 2 or 3
days - then prune again. A bottom leaf that
is supporting a fruit should not be removed until the fruit has been harvested. The leaves on the main stem will gradually be
removed as the fruit is harvested
It is important to maintain sufficient foliage on the plant for proper
photosynthesis. Excessive pruning of leaves
can cause the plant to quit producing flowers. However,
it is also important to maintain adequate air movement through the plant to reduce the
risk of fungus and insect problems.
Watch the growing point of the plant. It
may be necessary to increase water and fertilizer by 20% - 25% during times of heavy fruit
load. The growing point should be producing a
stem diameter of 1/2" and 1 - 2 flowers at each leaf node. If the growing point of the plant is weak as it
approaches the support wire, you may choose to remove flowers from the last 2 - 3 leaves
before the wire. This will allow the growing
point to regain strength and improve the stem diameter for growth along the support wire.
Lateral
Growing Techniques
About 30 days after transplant, the plant should be approaching the support wire. Unlike tomato plants, cucumber plants are very
brittle and you will break the stem if you attempt to “lean & lower” the
plants. There are several methods of training
the plants once they reach the support wires.
The “Trellis” method would have you run additional support
wires over the top of the aisle way. The
plants are then allowed to grow across the top the aisle way towards to plants on the
other side of the aisle. This forms an arch
with the fruit hanging down above the aisle.
The “Umbrella” method would have you terminate the growing
point of the plant about 2 leaves above the support wire.
Two laterals are allowed to grow from the plant (one in each direction along the
support wire). These laterals grow along the
support wire for about 8", then are allowed to grow back down 3' - 4'. This forms an umbrella shape.
The “Number 7” method will perhaps keep your plants the most
organized. Each plant is trained in the shape
of the number 7. The growing point of each
plant is trained to grow along the support wire in the same direction. The growing point is allowed to grow along the
support wire until it is 8" - 12" from the main stem of the plant next to it. As the stem grows along the support wire, 2
laterals (suckers) are allowed to begin growing. The
main growing point and the 2 laterals are then allowed to grow downward for about 3'. The plant has now been trained in the shape of
the number “7” with 2 additional laterals hanging from the support wire.
Once the original growing point or the laterals have grown down about 3' from
the support wire, their growing points are pinched out.
Removing the growing points will stimulate the plant to
produce more laterals. As the fruit matures
on each of the hanging vines, it is harvested. Once
all the fruit has been harvested from one of the 3 hanging vines, a new developing lateral
is located near the support wire. The old
hanging vine is then removed just below the new developing lateral. This opens a space for the new lateral to grow. It is allowed to grow down about 3' before its
growing point is pinched out. The cycle is
repeated on each of the hanging vines until the crop is terminated.
The “Number 7” method keeps the plants growing in an organized
fashion throughout their life cycle. It
utilizes the vertical space within the greenhouse without blocking excessive amounts of
light to the developing foliage. It provides
a way to renew the foliage growth, while keeping proper ventilation within the plant
canopy. Since each of the 3 growing points
are developing at different times, fruit production is maintained in a predictable
fashion.
Main
problems
Growers can experience problems growing cucumbers that are very similar to
tomatoes. The plants are subject to attack
from fungus, such as botrytis and Powdery Mildew.
Maintaining proper ventilation and relative humidity levels between 60% - 85% can
help reduce the incidence of fungus. Several
cucumber varieties are resistant to Powdery Mildew
Like most plants, cucumbers can also be attacked by a variety of root diseases;
such as fusarium, damping off, rhyzoctonia and pythium. The regular use of Mycostop, which is a
beneficial streptomyces bacteria that will grow around the roots of plants and help
shield the roots from attack from theses diseases, may help to reduce the problems from
these problems
Insect pests of cucumbers include; whiteflies, spidermites, thrips, aphids and
fungus gnats. As is true with most plants,
these insects can be controlled with the use of beneficial insects. However, it is important that the pests be
detected early and control measures be implemented before the insects get out of control. The use of insect barriers and yellow sticky traps
for early detection and control is important. Installing
an inexpensive misting system can help with humidity and temperature control and will also
provide an added benefit of slowing the rapid outbreak of spidermites and other insects.
Sanitation is very important. Keeping
the greenhouse free of debris and old plant material will help prevent the spread of
fungus and insect problems. Keeping the
outside of your building free from weeds and other insect attracting material, especially
around your intake vents, will aid in preventing a rapid invasion of insect pests coming
in from the outside
Harvesting
The harvest of cucumber fruit usually begins about 30 days after transplant. The fruit grows very rapidly. A flower will yield a 1-pound fruit in about 10
days. The weigh gain of the fruit can be very
rapid during the high light times of the year. A
3/4-pound fruit today will be a 1-pound fruit tomorrow.
Fruit is usually harvested when it weighs about 1 pound. Harvesting may be required every day during high
light periods. Fruit allowed to remain on the
plant can grow to an unmarketable size of 3 - 4 pounds and will sap the energy of the
plant.
When harvesting the fruit, it is important to remove the fruit stem back to
the main stem of the plant. Any
“stub” that is left can be attacked by the fungus botrytis. Harvesting early in the morning, while the fruit
is still cool, will help maintain crisp fruit. The
fruit is very thin skinned and should be quickly wrapped in stretch wrap or shrink-wrap
film to prevent moisture loss. Once the
cucumbers have been wrapped, they can be stored at 50When harvesting the fruit, it is important to remove the fruit stem back to
the main stem of the plant. Any
“stub” that is left can be attacked by the fungus botrytis. Harvesting early in the morning, while the fruit
is still cool, will help maintain crisp fruit. The
fruit is very thin skinned and should be quickly wrapped in stretch wrap or shrink-wrap
film to prevent moisture loss. Once the
cucumbers have been wrapped, they can be stored at 50o
- 55- 55o degrees F. for 2 - 3 weeks. You should avoid storing them with ethrel
producing fruits and vegetables, because this will accelerate their ripening process and
result in a shorter shelf life.
Wrapping
Machines
There are 3 different types of machines commonly used for wrapping cucumber
fruit. The size machine used by a grower is
dependent on the volume of production. The
smallest is a stretch wrap machine. These
machines are used in the meat and “deli” departments of most grocery stores. A grower can usually wrap 3 - 4 fruit per minute
with one of these machines.
A mid-sized wrapping machine utilizes an L-sealer and a heat tunnel to shrink
the film around the cucumbers. These machines
are widely used in industry to “shrink wrap” a variety of products. With an L-sealer and heat tunnel, a grower can
expect to wrap 15 - 20 fruit per minute.
A large cucumber grower may choose to use a special machine that is designed
especially for wrapping cucumbers. These
machines utilize 2 rolls of shrink film (one layer below the fruit & one layer above
the fruit). These machines are capable of
wrapping 100 - 160 fruit per minute
Target
Production estimates
Cucumber plants are capable of producing yields of 3+ pounds of fruit per
plant per week during the high light times of the year.
This is about 12 pounds per plant per month and across the normal 90-day harvest
period, yields of 30 - 35 pounds per plant should be the target production goal of a
grower. During the low light times of the
year, production will decline. Your target
production goals may drop to 1 - 1.5 pounds per plant per week
However, a grower who raises cucumbers on a year around basis (usually 3
crops), should target his annualized production at 60 - 90 pounds per plant space per
year. This could also be stated as an
annualized production of 7 - 10 pounds of fruit per square foot of greenhouse per year
Marketing
European cucumbers are eaten - skin and all - there is no pealing required
because the skin is not bitter. Unlike field
cucumbers, the fruit has not been waxed, therefore there is no waste to throw away. The fruit is very low in calories. The seeds do not mature, therefore they are
considered “burpless”. Once most
customers have tried these cucumbers, they never want to return to using “field
grown” varieties.
In the U.S., cucumbers are marketed in different ways. Along the East coast, cucumbers are sold in
12-pound boxes. In the Central and Western
part of the country, cucumbers are sold in 16-pound boxes.
These boxes are further defined by the size of fruit within the box. The most popular size is 1-pound fruit, therefore
a 16-pound box with a 16 count of fruit. However,
some boxes may be graded as 12 count (very large fruit), 14 count, and some boxes
containing smaller fruit may be graded as 18 count.
All fruit is expected to be a dark green color and free of blemishes. They are expected to be relatively straight and
evenly filled from end to end. If a slightly
curved fruit is placed on a flat surface, the arch should not leave a clearance of more
than 1" at the highest point. Fruit
with a curvature greater than 1" would be graded as a #2 quality.
Some large producers ship nationwide. There
are large growers in Florida, California, Mexico, British Columbia and Ontario in Canada. The majority of these growers begin their heavy
production during March & April and there is a secondary peak in production during
October & November of each year. This is
usually when the selling price of cucumbers goes down.
Many of these growers are out of production during the Winter months and
again during the Summer months. With less
available supply, the market price is high during the Winter months with a secondary peak
during the Summer months. The selling price
usually ranges from $1.99 - $2.99 per pound during the Winter months to a low of about
$.99 per pound during the Spring and Fall. Wholesale
prices are typically 33% - 40% less than the retail prices
The
Local Grower
A local grower always has the advantage of providing “fresh picked”
quality. However, European cucumbers are a
relatively unknown commodity. Many people
will confuse these cucumbers with zucchini or some other strange exotic fruit. It is the grower's responsibility (and
opportunity) to develop their own markets.
One method of developing a market that has been very successful for several
growers has been to set up a “demo table” in the produce section of local
supermarkets. Most produce managers are very
receptive to this because their section of the supermarket rarely gets the opportunity to
give “demo’s”. If the grower
can arrange to spend just 2 hours per week doing “demo’s” at the local
supermarkets, they will probably develop more demand for their product than they can
produce.
A “demo table” usually consists of a card table, a cutting board,
cucumbers and toothpicks. The grower provides
“free sample” slices for very everyone to taste.
Many growers will also put together a poster board of pictures and descriptions of
how and where the cucumbers are grown. Most
growers will also label their fruit and ask the customers to look for their label when
making purchases in the future.
In
Conclusion
European cucumbers are a fast growing crop that can be either grown as a
“catch crop” or as a primary crop. They
are distinctive in their appearance and flavor. They
can ONLY be grown in greenhouses. Many of the
same customers that purchase your other produce items may be interested in your cucumbers. Cucumbers could help you diversify your production
and allow you to deliver more produce to the same customers. |
