April 6, 2012

Growth rate of greens (or experiment number two!)

Even though the weather right now is not very winter-like I've started a second experiment.  Describing this one is much simpler:  I am going to see how different varieties of greens grow in the 'cold.'  The same kind of work was done last spring and fall and I'll be doing a lot more of it next winter.  

A few of the greens I'm growing are in this mixed flat.

The goal is to be able to estimate how long it will take green to reach a harvestable size as light and temperature levels change drastically in the fall and spring.  By the end I'd like the be able to say "if you plant lettuce in September you'll be harvesting in late october, but if you plant in october you won't be harvesting until december."

Arugula grown spring 2011

The chart above is a snippet of the data collected last year.  The temperatures are when the greenhouse heaters turn on.  You can see that keeping the greenhouse ten degrees warmer makes a big difference in growth (leaf length).  The length of the arugula grown at 40 degrees seems to be leveling off at around 40 days of growth.  If you knew it was not going to grow anymore you would harvest it at forty days.  Leaving it in the ground won't mean it was going to grow anymore.  The same observation can't be made for the arugula grown at fifty degrees - which is why we need more data!

What's going to happen:

I am growing ten varieties of greens:
  1. spinach
  2. kale
  3. green romaine lettuce
  4. red romaine lettuce
  5. arugula
  6. mizuna
  7. tokyo bekana
  8. tat soi
  9. ruby streaks
  10. scarlet frills
I'll make eight harvests at 3 - 10 weeks after planting.

At each harvest I will measure:
  • The length of 10 leaves of each species 
  • The weight of each species harvested
Pretty simple!  Are there any greens you would like to see on the list?  Leave a comment below and I'll take it into consideration for the next round.


  1. Hey, what a great blog you have!!!! I'm doing a research project on kale for my senior architecture thesis, as we're planning an urban farm, and your information is so detailed I am citing it as scholarly research. Are your leaf length measurements here in millimeters?

    1. Thanks! Your project sounds pretty interesting - what else are you thinking of planting on your farm? The measurements are millimeters, I should have put that on the graph. I would be careful citing this - it's probably considered 'unpublished work' or something like that.