Fall fuel use

While sifting through all the growth rate data I collected last fall, one thing I'm looking at is fuel use, and if using more fuel to speed up growth rate is cost effective. 

The greenhouses are heated by a furnace that blows hot air out (left).  They have a meter on them (right) that shows how many hours the blower has actually been blowing air out.  I record the number twice a week.  Since the meter is continuous I adjust the numbers to reflect the number of hours it was on for my particular experiment.  Oh-so-conveniently, the furnace uses one gallon of fuel every hour, so I also convert "hours" to "gallons."

The above chart shows total fuel use in each greenhouse.  Greenhouse one is heated to a 40 degree (F) minima and greenhouse two is heated to a 50 degree minima.  This doesn't mean that each greenhouse is at a constant temperature, it means the temperature will not fall below the given set point.  You can see this created a big difference in how much fuel was used. 

Since 'gallons of fuel' is a bit arbitrary to the non-greenhouse owner, lets attach monetary values (everyone understands dollar signs). So,

Greenhouse 1: 108gal x 3$/gal = $324

Greenhouse 2: 264gal x 3$/gal = $792

That is a big difference!  But is it economically worth it to heat the greenhouse to a higher temperature?  Will that make greens grow faster?  Or is it just throwing money down the drain?   That's what I'm working on figuring out (but haven't done so yet!).

* As usual, this data pertains only to our greenhouses this fall.  It is not complete and should not be used elsewhere.  If you are looking for data pertaining to winter greens growth, fuel use and temperature you'll just have to wait until I'm done with my thesis! *

Help needed!

In the coming fall and spring I'll be looking in depth at the growth rate of six greens throughout the season.  The list includes: mizuna, tokyo bekana, tatsoi, spinach, and green romaine lettuce.  I need help picking the sixth variety. Here are the options: 

Scarlet frills: red, curly leaves, from the brassica family,
has a mustard-y flavor that can be a bit spicy when weather is warm.

Red russian kale: Also a brassica, known for being cold weather hardy, 

usually grown for mature leaves (not baby size for salads).

What do you think?  Are there other varieties you think should be on the list?  Leave me a comment (via facebook or the little pencil on the actual post) or send an email.  I can see how many people view the post so I know when you're not replying!  It's for science!

(I will be doing a variety trial of 20 greens once in the fall and once in the spring to look at lesser known varieties like vitamin green and tatsai.)

why fall is a bad time to start vegetables

I am getting all excited about growing lettuces and new varieties of greens that I haven't seen before but now is just is not the time.  It is still warm enough out but the real issue is lack of light.  At this time of year - late fall - five o'clock comes around and it is dark as midnight.  This affects plants just as it affects people.   Less than ten hours of sunlight significantly decreases the amount of growing leafy greens will do.

These little spinach plants illustrate this idea.  They were planted over a month ago and have a nice warm growing space inside a cold frame but grow very slowly because day-length has been decreasing.  Combating this dilemma is simple but requires a bit of planning (or planting!) ahead.  Greens and some other vegetables planted in late August and early September will have had ample time to reach maturity by now and will continue to "hang out" in the garden for a long time even when days are short and the nights get chilly.

Kale is a perfect example of cool hardy vegetable that will live in the garden.  Just make sure you plant extra at then end of summer.   Most cool hardy vegetables can survive light frosts.  Further protection from cold frames and row covers can help stretch the season a bit longer.  Cooler temperatures increase sugar and nutrient levels in vegetable making them even tastier.