Spraying for Mildew

  It seems that some chemicals need to be approved before being used in a greenhouse, such as one for spraying mildew.  Pristine was just being used at 248 on the cucumber plants.

Carl adjusting the intensity of the spray.

  The solution mixture ratio is 40 grams per 100 liter of water.  We will add more if the mildew condition is really bad.  Some chemicals are also known to kill mildew and spidermites as well, but they may be illegal to use.  Mildew is easily killed, as just water itself can pop their spores.  We use Pristine because it stays and continually kills the spores when they pop out.

  According to Carl, to find out if the mildew infection is gone after spraying, we check the mildew spots after three days to check for the presence of brown spots instead of white spots. We usually just spray on top of the plants, but we can also spray from the bottom and then the top for more protection.

Carl spraying from below the leaves.

Carl going backwards and spraying the top of the leaves.

Carl spraying the walkway in the end.

  Currently we buy 1.8 liter Pristine for $800.

Importance of Space and other Needs for Plants

  From what Carl has taught us about understanding the plants' needs, we need to imagine and to relate ourselves to plants:  If we are a plant in a greenhouse, what would we need?  For example, there will be weeks of hot weather during summer, and how would we know if the greenhouse is too hot?  The answer is simple: If we, the workers in the greenhouse, can feel the heat and the need to cool down and drink more water, the plants will need to as well.

  As silly as it may sound initially, treating plants as someone like us is easier for us to understand their needs.  Space for plants must not be neglected - cramming too many plants per square meter will result in plants not getting enough sunlight in the future.  We all want huge output,but 2.5 - 2.6 plants per meter squared seems to be the recommended density.

  Plants do get stressed out as well.  According to Kyra, when the weather gets very hot, ~27 degrees celcius and above, plants are usually stressing at that point.  If we pick or prune or twiddle when the plants are stressing, it usually results in the plants "giving up" and they end up not producing anymore output.  This is important to note, and it is the reason why workers do not usually do anything with the plants after 2pm, which is when it gets really hot.

  Plants also need sufficient space above them called buffer.  Note the picture below:  The space above the plants' heads to the beams supporting the roof is the buffer zone.  Buffers are important for the air to mix inside the greenhouse for stable and equal temperature and heat throughout the greenhouse, which is aided by fans hanging above the plants.  The larger the buffer, the better it is for the plants.  For example, tomatoes need huge buffers to prevent their heads from overheating and killing the plant since they grow very tall. 

Poly sheets covering that is used for protecting against
scorching sunny days or containing the heat
inside the greenhouse during cold weathers.

  Notice the sheets that is being dragged slowly to the right.  This poly sheet wears out every 2 years and needs to be replaced.  It protects the greenhouse from heavy sun rays and also prevents the heat from leaving the greenhouse during cold days. 

More sheets at the side, but this is always there and
only replaced and taken down during clean up.
Note the generous buffer zone for the plants.

Water System for a Greenhouse

Currently at Merom, there is one giant big tank outside the facility for hot water circulation. The water is heated in the boiler room using natural gas instead of the wood burner since it's more cost efficient.  That tank is part of the enclosed heating system for the entire facility, including phase 1, 2 and 3. All the water is circulated, and the tank contains sensors for both the temperature and the water level. If the water level is below a certain level, alarm will notify the facility. The tank also contains 9 temperature sensors, making sure the water is not boiling but kept at a relatively high temperature, around 92-98 Celcius.The water must not boil since it's an enclosed system and the air is not pressurized in the tank.

Hot Water Tank

If the water level drops below a certain level, then we know there is a leakage somewhere in the system since everything is enclosed and all water does not escape. Natural gas is used to heat up the water, and it mixes with cold water in a mixing valve to obtain the desire temperature before sending the water off to the heating pipes to heat up the greenhouse.

The Greenhouse Structure And the Fertilizers

Current greenhouse is relatively small by size.  It features two front entrances: a normal door and two sliding doors.  There's also two sliding doors in the back of the greenhouse which is used for dumping bad crops and trimmed plants.

The greenhouse currently uses three fertilizers: Magnesium Sulphate, Potassium Nitrate, and Calcium Nitrate.

Four buckets containing mixture ratios of fertilizers.

Huge tanks containing water.

Steel wires are hung across the greenhouses from
one end to the other for the strings' supports.

The sliding doors at the back of the greenhouse
for dumping bad crops and pruned materials.

The unused entrance.

Carl usually opens these sliding doors and move
his truck here for picking up/dropping off totes.

Two unused offices.  One of them contains the computer
system governing all the
water supply/window opening mechanisms.

Heating pipes which also work as railings.

Pipes protrude onto the cement floor
for easier cart maneuvering onto the pipes.

Steel chains supporting more
steel wires for the strings supports.

Some strings don't need chains; they are
supported by the beams of the structure.

Collected strings from fallen plants.

Basic cart and totes.

Stopping Waterflow To Certain Rows

To save money on water, we cut off the water supply to certain rows, such as a row of dead and drying tomato plants.  Do be careful to not cut off water supply accidentally as some rows may contain a few alive plants.

One end of the water pipe supplying water to
the watering tips.

The other end of the water pipe is usually
connected to the main water supply pipe.
In this case, a cap is screwed to the
main water supply pipe to stop the water supply.

The front end of the water pipe can also be "folded"
and "locked" with a PVC pipe instead of a cap.

Notice that the caps at the ends of the pipes are the same, so we could just unfasten the cap at one end, which is the shown in the first picture, and use that to block the white main pipe from supplying water to the black pipe.

Clipping Cucumbers on Wire

Kyra clipping cucumber plant on wire.

When a cucumber plant is long, we throw it over and wrap around the wire, similar to twiddling except we twiddle the cucumber plant's head around the wire.  When the plants are young, wrapping it around the wire once is suffice, and then clip the area near the head, where we let the head start growing downwards.  If the plant is longer, it may be necessary to wrap it two to three times more around the wire before using clips.

Sometimes, when the plant is older, they start to sag downwards from the wire if the string supporting the plant is not properly twiddled and tied to the wire correctly.  A clip has to be applied there in order to prevent the plant from tearing and splitting from the weight of the plant and the sharp wire.  Another clip should also be applied at the other end where the plant will continue to grow downwards so the plant looks like it is growing around a door frame.  One clip is the minimum for a plant, and it is usually applied at where the head of the plant will be growing down, though two clips per plant is just as common in order for the plant to have a door frame shape if the plant is sagging away from the support string.

A clip is only needed on the right corner because
the left corner is strongly supported by the string.

A sagging plant on the left corner,
a clip will have to be added.

After applying clip to the left corner.

There are two ways to apply the clip:  One can apply the clip to the wire and then gently allocate and push the  stem into the clip, or one can clip the plant first and then clip to the wire.  Either way works, but wearing gloves for the hand that is holding the clip helps a lot in navigating through the thorny leaves and stems of the plant.  Two gloves are not recommended since one can accidentally break a stem when clipping a plant.  The ungloved hand should be used to allocate the plant gently into the clip.

Take note to not impede any growing cucumber's growth when clipping.  Growing cucumbers and their stems should not be in the clip.  The clips are reusable and can be removed be simply turning the clip to the left or right and then push up, like a counterclockwise or clockwise motion.

A good example of properly clipped plant.
Two clips support the heaviest points.

Cutting Off Grape Tomatoes/TOVs

When tomatoes are no longer harvested (or would be harvested few times), we cut off the bottom of the stem to kill off the plant.  This makes the plant to wither and thus easier to collect after a day.

Cutting off the stem of a tomato plant.

When the plant is withered, we start collecting them into piles for disposal.  We reach to the top of the string and cut, which will shoot up the string roll off the steel wire on top.  Note that we need to reach higher than the last clip that clings the string and the plant together or else the string roll will not pop off.

Uncut, healthy vines.

Cut, withered vines

Tools involved.  From the left are the scissors, string roll, and gloves.

Piles of cut tomato vines.

We give a quick roll to the strings to make sure they don't get tangled and drop them to the ground.  After piling up all the cut vines, we roll a cart to pick them up, and off to the compost they go.