What did I plant? Telling apart sprouted greens

Does this happen to you?  Do you plant things and forget what they are?  I certainly do! (See vates kale.) It's pretty easy to tell what family salad greens are in based on their cotyledons.  You might not be able to tell what variety is growing, but at least you'll be able to tell the lettuce  and spinach apart.

When lettuce sprouts it's small and cute - the bunny of the salad greens.  The cotyledons spread wide open on the soil surface.  Red varieties of lettuce will change color if it's warm and sunny. 

Spinach cotyledons are long and slender, forming a 'V' shape.  

All brassicas have heart shaped cotyledons.  This includes leafy greens and cole crops (cauliflower, cabbage etc).  The picture above shows tokyo bekana, kale and scarlet frills.  Cotyledon size varies between varieties, and so some brassicas make good microgreens.  Broccoli, although not a salad green, is a good example.

Members of the beta family, including swiss chard and beets, are also good microgreens because their stems are often bright colors.  I've taken a lot of photos of them because of this.  Their cotyledons are oblong with a slightly pointy tip.

Field day: Germination

Photo friday: spinach germination

The past few days have felt like we have turned the corner towards spring.  Birds are out, the ground is muddy and there are buckets on the sugar maples.

Corvair spinach

I have been tired out for the past week, despite two greenhouses filling up with cheerful, green seedlings. After a week long blogging break I am back!

Much of what I'm doing this spring is a repeat of last fall's experiments.  The major difference is the new spinach variety, corvair, which is resistant to 11 strains of powdery mildew.  The first true leaves have started to emerge and already I am in love.  Corvair has much rounder, upright leaves than space.  These were major selling points when I was deciding what variety of spinach to use.  Sunny days keep the greenhouses between 60 and 70 degrees, which is pretty nice to work in.

First spinach seedlings of the new year!

I was going to write about growing degree days, but who wants to read about that on a Friday?  Plus, the spinach I planted ten days ago is sprouting!  After the trama last fall seeing these new spinach plants has cheered me right up.  So has this little guy:

Last week I knocked over some lettuce seeds into a tray.  They were too wet and dirty to plant with the vacuum seeder, so I stuffed them in a little pot. 

First seedlings of the new year

It is a happy day when seeds start to sprout.  I planted these just ten days ago!  I don't know what the brassicas above are, then are labeled "bottom of the box" because I found them at the bottom of my seed box.  They might be tokyo bekana.

Defender lettuce is starting to sprout too, but only in the warmer greenhouse. 

Seed germination results

I am about half way through the seed germination experiment.  Already trends are appearing in the data.  So far, I've germinated seeds at three temperatures: 75, 65 and 55.  On really hot days I want to crawl into the growth chambers and hang out with a book until it's cooler.  Hopefully there won't be many more hot days this year.   

The maximum number of seeds at each temperature is 50.  So, for defender lettuce at 75 degrees all the seeds germinated by the third day.  As the temperature decreased it took longer for seeds to germinate, and germination was spread over a number of days.  This is useful because it tells a grower or farmer that they don't need to heat their greenhouse all the way to 75 or 65 degrees to have good germination of lettuce seeds.

The pictures on the right don't show what I'm seeing when I count germinated seeds - but they are far prettier.

Tokyo bekana shows a slightly different trend.  Days to germination is similar for seeds sown at 75 and 65 degrees.  At 55 degrees seeds take much longer to germinate, and the percentage of seeds that germinated is much lower.  (You can't tell this from the graph, but it's true.)  So, how is this useful data?  It shows that temperatures lower than 55 degrees will result in poor and lengthy germination compared to warmer temperatures for tokyo bekana.  Eventually I'll add fuel price in as a component to this study, but not until I'm done collecting data.

Experimental design - germination in chambers

Germination: cotyledons and true leaves

Last time I wrote about the radicle end of germination.  These posts certainly make you think back to beginning biology class!  After the radicle appears from the seed and goes down, the hypocotyl goes up.  Embryonic leaves, called cotyledons, appear and start to photosynthesize.  Of course, grasses are different, but I'm not growing any grains so it doesn't matter.  

Cotyledons aren't true leaves, and often they are shaped differently than the true leaves.  Brassica cotyledons are heart shaped.  Spinach's are long and skinny.  They can get very big on some greens, namely tokyo bekana, but I never measure their leaf length, or included them in the harvest weight.  They can be used as microgreens though.

Spinach cotyledons.

True leaves appear shortly after.  They are cute, tender and grow pretty quickly (unless it's really winter).  Can you identify the variety below?

Germinating seeds: radicles

This week I wrote a very long email to a friend who is starting a garden - in Namibia!  She and her villagers are beginning gardeners.  At one point she wrote "the swiss chard seeds had little germination root thingys in the package."  Those little thingys are radicles, or embryonic roots, and I have been looking at a lot of them recently.  If they were in soil, and not on petri dishes, they would grow down.

Root hairs also collect water.  Cotyledons are embryonic leaves I'll write about them next.

Right now I'm germinating seeds in growth chambers to see how temperature affects germination rate.  It sounds fancy, but it really isn't.  Growth chambers look like refrigerators with a panel of dials to control temperature, humidity and light.  The only parameter I'm changing is temperature.  Right now the temperature is set at 75 degrees.  Next week I'll start over at 65 degrees and so on down to 35 degrees.

The wires and box are the temperature monitor.

The seeds go in petri dishes with wet filter paper.  Every day I look at each one to see how many seeds have sprouted.  It sounds labor intensive, but isn't.  Yesterday I had everything counted in 15 minutes!  Partly because most of the seeds have sprouted and partly because a huge storm descended on southern New Hampshire and I had left all the windows in my apartment wide open.  I expected a flood when I got home and was relieved at a broken flower pot. 

Seed, radicle and beginning cotyledons under the seed shell on the left.

Sprouting seeds on my countertop

After just 30ish hours I have hundreds of seeds sprouting in petri dishes on my counter.  I'll explain why I'm doing this later once the experiment really gets going.  Right now I'm just observing what seeds sprouting in petri dishes look like.  Aren't they cute?

UNH greenhouse open house

Why be excited about this event - besides that it is about plants which are always worth getting excited about?  Because I am going to have a poster and some plants from the germination trials experiments!  I printed the poster out today and it's all shiny and official looking.  You can see it below.  Many of the pictures should look familier if you've been following me.  To actually be able to read the words you'll just have to come to the open house on Friday and Saturday!

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?

Lettuce and mizuna at 42 days old

Lettuce seedlings at forty-two days of growth.

I am still thinking of different ways to compare the seedlings as they grow.  Here, I pulled the seedlings straight from a cell without being delicate at all.  They are lined up from left to right by treatment: control, clear plastic, white plastic, plastic with holes, row cover, heat mat.  Most of these little lettuces have wimpy little root systems.

Look at that last one on the right!  It is nearly a plug!  I suppose it seems obvious that using heat mats to keep the soil warm will stimulate root growth.  The leafy part of this plug seems to be about the same size as three of the other treatments.

The biggest leaves come from the clear and white plastic treatments.  Because of the non-porous nature of plastic water was retained in these two treatments making them pretty humid.  My data collection notebook was often spattered with condensation falling from the ceiling of these tunnels.  If I had any forethought I would have used my super cool waterproof notebook and a pencil to do all the data collection, but I didn't and have lots of crunchy, dried out pages of data to prove it.

Mizuna seedlings at 42 days old.

In contrast here are mizuna seedlings lined up in the same way: control, clear plastic, white plastic, plastic with holes, row cover, heat mat.  They all have strong root systems and look pretty similar.

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.

One week of growth

Although I have finished data collection for the germination trials, I have been observing the sprouted seeds as they grow.

Lettuce from white plastic, plastic with holes and clear plastic low tunnel coverings.

I've commented before on the pigmentation of lettuce grown under the different low tunnel treatments.  Those little seedlings have grown quite a bit in two weeks, but the pigmentation patterns continue.

I planted plugs in trays of soil on the 13th of February (on the left).  A week later the greens look fuller and many of the plugs have more leaves.

These pictures of arugula are also from the 13th and 20th of February, respectively.  In just a week the seedlings have gone from cotyledon stage to the true leaf stage.  

Today I am going to plant a few herbs to see how they grow in the tunnels.  I am thinking about dill, cilantro, parsley and basil.  Any other ideas?  What would you like me to try growing?

One month old mizuna

After a month the mizuna grown under clear plastic is a good sized plug.  Look at all those lovely roots!  I've planted a few in bigger pots to see how they will grow.

Observations on spinach

Total seeds sprouted by species (aka Real Data!)

Total number of seeds sprouted by species over a 20 day period

Would you look at that - a real chart from real data.  Pretty cool right?  (I think so!)  Since there is so much data it's good to start by looking at the big picture.

These are the spinach, lettuce and mizuna seeds planted in all those different low tunnels we built for the germination trials.  I noticed germination trends by species and decided to ignore the fact that the seeds were grown under different conditions to compare the three species.  This chart shows distinctive germination characteristics of each species:

• Mizuna, the fast growing mustard green, was the first species to have any seeds germinate.  The germination rate increased quickly from days 9 to 12 and then started to decreased.  Of the 3360 mizuna seeds planted 60% of them germinated.
• Spinach is known for being a plant that can grown in cool conditions, but like many cold tolerant crops it would prefer to germinate at warmer temperatures.  Here we see that it is slower that mizuna to start germinating but, that 14 days after planting there is a huge spike in germination.  Spinach had a 71% germination rate.
• Lettuce is not a very tough plant.  Only 52% of the seeds germinated and it took nearly 20 days for that to happen.

That's just the beginning of looking at all the data.  Besides germination rates there is also temperature and light data to take into account.

* Because I am a grad student this chart is built with  Real Data, but in no way am I recommending anything other than being excited about plants and eating.  *

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.