Crop Choice and Water Temperature

The summer and autumn seasons of my greenhouse aquaponics were a limited success.  I grew edible crops and found ways to combat excessive heat gain in the greenhouse with materials I had on hand.  Winter has presented a more difficult challenge.
My tomato plants were killed by the low temperatures of early December, however the herbs I planted in the other half of my bins have survived the cold and remain green.  The attempt to heat the greenhouse with a chimenea turned out to be destructive of the insulation on the ceiling, but the insulation which has deformed and withered probably kept the polycarbonate roof from melting.  I plan to do more work on the use of other methods such as a rocket mass heater, but at this time I will continue to use a propane heater to moderate the air temperature.
We have now focused on keeping the water system stable and preventing freezing.  We have a titanium fish tank heater on order and we have wrapped the pipes in the system with heat tape and added tube insulation.  Freezing in the pipes creates imbalance in the dynamic flow of the bell siphon system.  It also threatens structural damage to the tank and pipes  if the water freezes hard and expands.
Herbs and green vegetables such as spinach, mint, beet greens and cabbage resist cold air temperatures and continue to produce in the winter.
I can start crops like strawberries and tomatoes earlier in the greenhouse and keep them longer as the weather cools, but it is evident that I should switch them out for more hardy crops before sustained sets in.

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Temperature

These are temperature charts from http://www.knowledgeweighsnothing.com/when-to-plant-vegetable-seeds-2-excellent-printable-charts/

Today is February 14th .  Today is expected to range between 39 - 72. The slightly warmer temperature is causing the  my watercress which were planted months ago to double in size within the past week. Watercress likes cool weather in the low 50F.  I will be planting more of it outside in my bioponic system.

I took this picture of the bioponic raft on December 19 2012.  It been 2 months heres the difference. All most all of this growth took place during the past two weeks since out temperatures have gone up.  Keep in mind that I picked about the same amount that I started with just a few days ago.

 

The mustard and arugula in this first picture (red arrows) were transplanted from the start bed shown in the second picture.  The difference is the raft stays several degrees warmer due to a constant flow of water from the bioponic sump tank buried in the ground.  The start bed was kept moist, but watered only as needed with the same boiponic water.
Arugula planted in the indoor system was been eaten weeks ago.
Just goes to show how important temperature is.  The same goes for our hot Summers.  Lettuce and cilantro do not do well when it gets hot.

The watercress in the foreground was transplanted and is actually OK as is the agave which did not like the freezing temperatures

These are the AVERAGE temperatures for Chico, CA

http://www.weather.com/weather/wxclimatology/monthly/graph/USCA0211

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Root Zone Heating and Insulation of Greenhouse

When I intended to use my greenhouse mainly for storage I installed a double layer floor over the native dirt instead of using gravel.  I wanted a surface I could easily clean.  The first layer consists of 3/4" thick mats of recycled tire rubber which had been used as an athletic floor in a gym.  Over this I placed an indoor/outdoor carpet that extends from wall to wall.  This flooring has proven resilient to flooding.  I recently learned that insulating the floor of a greenhouse is a good idea since the earth itself can suck a lot of heat energy out of the greenhouse.  The thick black rubber floor makes a good insulating layer.  Years ago I purchased a large amount of mylar faced bubble insulation which was on sale with the intent of using it in a projected construction project that never was realized.  I have been able to use this material in the lower wall areas of the greenhouse where transparency is of no value.  Because it has both insulating properties and is reflective, I plan to use it under my nutrient film trays to retain the heat provided by a 40 foot seedling heating wire.  Adding and retaining heat are my chief concerns at this time of year.

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