Growth rate observations - problems

Not all things are happy and cute (like microgreens) in the greenhouse.  Here are some of the problems I've observed in the past few weeks.  In the picture above the lettuce is substantially smaller than other lettuce planted in the tray next to it (you can't actually see that from the picture, you'll just have to take my word for it).  The spinach germinated very poorly.  Look at all that dirt!  Since I use the vacuum seeder to plant I know there should be more spinach growing.

Next up, curly spinach leaves.  The leaves were also curling from the edges in, making them look like long, skinny green scrolls.  Who wants to eat that?  Potentially, it was due to the very, very low light levels this weekend.  See how long and stretched the mizuna seedlings are below?    That's also due to low light levels.  None of the plants are hurt.  Since there was a bit of sun in the past few days the spinach leaves have uncurled.

Growth rate research questions

Since my growing season is over, and I no longer have any plants in the greenhouse, most of my time is spent organizing data, writing and trying to answer all my research questions.  I have lots of questions.  The ones below pertain only to the growth rate of greens and the economic of growing them because that's what I am thinking about right now.

Germination trials: Recap

It's come time to wrap up the Germination Trials so we can move on to the next experiment before the winter season is over.  I won't finish analyzing the data until this summer when I have more time, but  there are a few conclusions that can be made now:

 1.  The different treatments did have an effect on % germination rate and days to germination for all three varieties of seeds.

 2. The three species of greens responded differently to the cool, wintery conditions in terms of germination rate. 

3.  How all the temperature and light data tie into the germination rate will have to wait until I have more time.

As with all experiments, new questions for further experimentation arise.  The questions I'd like to explore in the next experiments are:

• How do the tunnels affect growth rate?  I showed that there seemed to be differences in growth post-germination.  Now it's time to actually measure it.
• What about other species?  We only looked at three species of greens.  What about green leaf lettuce, arugula, kale or tat soi?
• Would combining treatments be advantageous?  Putting heat mats inside clear plastic tunnels seems a good combination to provide root zone heat, above ground heat and a humid environment.
• What questions do you have?

Comparing growth post germination

These seeds were all planted on the 13th of January, so the seedlings are now 42 days old.  I tried to pick a good representative tray from each of the treatments  to take a picture of.  A few of the observations that can be made I've written about before, including: lettuce pigmentation and the different germination rates of each species. 

From these pictures it seems like the plastic with holes had the most uniform lettuce growth.  Since I haven't actually been looking at growth rate, I can't demonstratively say that.  But, the plastic with holes lettuces seem to have mostly sprouted and are of similar size compared to the white or clear plastic.  The spinach seedlings seem to be the most consistant species between the six treatments.  The mizuna seems long and leggy in the plastic treatments and shorter in the others.

January light

Lots of light is not a requirement to sprout seeds.  But, light is one of key reasons plants grow and are just so cool.  Taking light and turning it into sugar is pretty amazing.  When I see people outside tanning I know they are just trying really hard to photosynthesize.

Since we had light meters available we set them up to give us a reading of the total moles of PAR light each day.

Moles of light measured in tunnels on a cloudy day (Jan. 27) and a sunny day (Jan. 28).

In January the days are starting to get longer, but they aren't really that long yet.  I graphed the two days above because one was cloudy and one was sunny.  The difference in amount of light that reach the sensors (and thus the plants) is pretty apparent.  There are a couple observations between the different tunnel coverings that deem pointing out:

1. Here it shows that the clear plastic and row cover transmitted about the same amount of light.  Sometimes this is true, and sometimes the clear plastic transmits more moles of light.
2. The white plastic transmits more light than I thought it would and isn't that far behind the other coverings.  The seedlings inside the white plastic treatments are much more etiolated and spindly than all the other seedlings though.

Do you see anything interesting?  If you grow greens in high tunnels, low tunnels or under reemay do you ever worry about light?

* This data is pretty cool, and will be useful for writing my thesis.  

I am not recommending anything besides excitement and interest in plants and photosynthesis. *

Observations on lettuce

I have been looking at germinating seeds for nearly a month and have become quite intimate with these 10000 seedlings.  It takes about two hours everyday to go through all of them.  Such devotion leads to observations.

Lettuce seeds are tiny and their seedlings are tiny too.  So small that I couldn't get a very good picture of a newly emerged seedling.  Their two cotyledons are held together when they first emerge and slowly open like butterfly wings.

Soon after sprouting these seedlings turn dark reddish because they are a red variety of romaine lettuce. It can make them a bit hard to spot when counting.

The seedlings in under the opaque white plastic and the clear plastic don't change color.  They remain a lovely green with a bit of red mottling.  

Germination trials: measuring light

How much light is actually reaching the inside of the greenhouse?
How much light gets through the low tunnel coverings?

To answer these questions we use watch dog weather trackers.  They measure:

    ~ average daily temperature

    ~ daily high and low temperature and the time at which they     

       happened

    ~ amount light in moles/day

Pretty useful little things.  

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.